How is Methanol Produced in Moonshine? – via GIPHY Methanol is a by-product produced during the fermentation process of making moonshine. During fermentation the enzymes in the yeast are responsible for converting the fermentable sugars into energy for the cell.
Contents
How does methanol get into alcohol?
What is methanol? – Methanol is the simplest form of alcohol. It is closely related to ethanol, the type of alcohol normally found in beer, wine and spirits – but much more toxic. The potential for its presence in drinks made from home-distilled spirits is a serious health risk.
Methanol is formed in very small amounts during fermentation, the process by which alcohol is made from plant products like grape juice or cereal grains. There are small amounts in wine and beer, but not enough to cause problems when these products are made at home, says Leigh Schmidtke, a senior lecturer in wine microbiology and production at Charles Sturt University.
But home distillation to make spirits like gin or rum concentrates the levels of both ethanol and methanol. Commercially-made spirits are very safe because manufacturers use technologies specifically designed to ensure methanol is separated from the ethanol.
What causes methanol in fermentation?
Methanol is produced during fermentation by the hydrolysis of naturally occurring pectin in the wort (Nakagawa et al.2000; Mendonca et al.2011). PME de-esterify pectin to low—methoxyl pectins resulting in the production of methanol (Chaiyasut et al.
How can you tell if alcohol has methanol in it?
Introduction – Toxic alcohol consumption is a major cause of mortalities and morbidities worldwide, Although drinking alcohol is prohibited in Muslim countries and there have been major penalties determined for alcohol use in them, recent statistics show that these penalties have failed to decrease the frequency of alcohol use or misuse in some of them,
This has resulted in increased use of black market alcohol which may potentially be methanol-contaminated due to the lack of observatory quality control processes and outbreaks of methanol poisoning in different parts of the world, Considering the Eastern Mediterranean Region (EMR) as the region with Islamic countries within, both men and women in this area have the highest weekly heavy episodic drinking among drinkers in the past 12 months in both males and females worldwide,
The worldwide consumption of ethanol was equal to 6.13 l of pure alcohol consumed per person of 15 years of age or older in 2005. A large portion of this consumption – 28.6% or 1.76 l per person – was homemade, illegally produced or sold outside normal government controls,
This increases the risk of introduction of hazardous chemicals into the ethanol, the most important of which is methanol, Both unsupervised production of alcoholic beverages and lack of quality control processes during their production increase the risk of contamination of the produced alcohol with unwanted toxic components including methanol.
Therefore, during the process of quality control of production of such beverages, it is generally important to be able to determine the presence of sufficient methanol concentration capable of resulting in poisoning. Police were usually asked to investigate the discovered consignment of suspected alcoholic beverages and report its content to the judiciary system to determine their alcohol concentration.
- Based on Iranian legal medicine organization protocols, liquids with 3% v/v ethanol or less than that are not legally considered to be alcoholic beverage at all.
- The gold standard method for determination of methanol content in alcoholic beverages is gas chromatography (GC).
- However, this technique is expensive, calls for considerable knowledge and experience to be performed, and is not readily available in many developing countries although this technique has previously been used even in mass poisonings,
Having access to a safe, cheap and easy method to prove the absence of unauthorized quantities of methanol before ingestion is therefore highly advantageous, Generally, with the same methanol concentration, the possibility of toxicity increases with reduced ethanol content.
Ethanol has a 20 times higher affinity for liver alcohol dehydrogenase enzyme which prevents methanol metabolism when blood ethanol level is 100 mg/dL or higher, Previous studies declare up to 5 mg/dL serum methanol level as the acceptable concentration of this toxic agent in human blood, Reaching this methanol level in an average 75-kg adult with about 41 l of body water (55% of the total body weight) would roughly be possible after consuming 251 mg methanol in 1–2 h.
This is approximately equal to 2.5% v/v absolute methanol in water, Thus, determination of the maximum acceptable methanol to ethanol concentration in an alcoholic drink without risking toxicity is a challenging concern. The “maximum safe” concentration of methanol in alcoholic beverages has previously been determined based on “permitted and safe content of methanol in the beverages” regulated by the European Parliament and the Council (4000 mg/L in alcoholic drinks with 40% v/v ethanol concentration) and US national research council of the national academies (Table 1 ),
Therefore, “maximum safe dose” is defined to avoid a serum methanol concentration more than 5 mg/dL, Table 1 Methanol Concentrations in Food and Beverages We used a new kit designed based on the modified chromotropic acid (CA) method for this purpose. Using this kit, the relative concentration of methanol to ethanol is estimated since methanol/ethanol ratio can predict the potency of the drink to induce methanol toxicity.
Therefore, a positive test would indicate an unsafe beverage and the possibility of methanol poisoning. We picked a conservative approach to evaluate the potency for both acute and chronic methanol toxicities. The table for safe concentration of methanol in different food products and beverages (USA standard) was therefore used (Table 1 ) which determined all drinks with any concentration below the permitted levels as safe beverages.
- Preliminary evaluations confirmed the efficacy of this kit in determination of possible toxicity risk of the alcoholic beverages,
- The aim of the current study was to firstly evaluate the methanol and ethanol contents of the suspected alcoholic beverages discovered by Iranian police as sample of the alcoholic beverages available in the Iranian black market using GC as the gold standard method.
As a second aim, we assessed the potency of toxicity of these suspected samples by detection of relative methanol to ethanol content using a new kit based on modified CA method and compared them with the results obtained by GC in order to determine the efficacy of the designed kit.
How do distillers get rid of methanol?
2.1.3. Inhibition of Pectin Methylesterase by Sterilization of Mash – A significant reduction of methanol by 40–90% can be achieved by thermal deactivation of pectin methylesterase (often referred to as “mash heating”). There are various suggestions for temperature/time combinations to achieve the enzyme’s denaturation.
- Sterilization at temperatures higher than 70 °C was generally suggested to effectively prevent the production of methanol by inactivation of pectin methylesterase,
- Methanol can be reduced by targeted thermal deactivation of pectin methylesterase by heating the mash to 80 °C up to 85 °C for a holding time of 30 min or to 60 °C for 45 min,
Pasteurization at 72 °C for 15 s prevented the production of methanol in fermented plant beverages containing Morinda citrifolia (noni fruit), In cider spirit, the pasteurization (30 min at 50 °C, then heated to about 85 °C) of the apple juice prior to fermentation reduced the methanol content by 34–46%,
- Lower methanol levels were obtained in Williams and plums by heating the mash to 65 °C for 5 min, followed by re-cooling for fermentation,
- Xia et al.
- Confirmed that autoclaving by steam injection of the mash of jujube reduced the methanol content in the spirit significantly by a factor of about eight.
The authors also determined pectin methylesterase activity confirming that their treatment method reduced the activity to one-fifth to half of that without treatment. Further technological approaches for inactivation of methylesterase are thermosonication (ultrasound plus temperature at 70° led to 30% methanol reduction in plum wine) or use of microwaves (70 °C for 1 min led to 70% methanol reduction in plum wine).
Does honey fermentation produce methanol?
4. Methanol: Spirits Occurrence and Legal Limits – Upon leaving the alembic, the distillates obtained from different raw materials are mostly made up of alcohol (ethanol) and water. In addition to these two ingredients, the distillates have in their composition large tens of volatile compounds.
- The most abundant volatile compounds in these distilled spirits are the fusel alcohols, the fatty acid esters, together with acetaldehyde and methanol, and sometimes these compounds are called major volatile compounds.
- In the major volatile compounds, quantified in the spirits, the methanol is normally included, as can be observed in Table 1,
This table shows the maximum and minimum levels of various major volatile compounds, quantified in different types of spirits, obtained in Portugal. The major volatile compounds usually include various alcohols that result from yeast metabolism during the fermentation process, namely 2-butanol, 1-propanol, 2-methyl-1-propanol, 2-propene-1-ol, 1-butanol, and the isoamyl alcohols.
- They also include an ester and an aldehyde, respectively ethyl acetate with a characteristic varnish aroma, and acetaldehyde with an oxidized or green apple aroma, which are also formed during fermentation,
- In the case of acetaldehyde, its content may increase due to oxidation processes, which may occur when the fermented or distilled product is kept in contact with air,
On the contrary, the methanol appears in spirits in varying contents, but it originates from enzymatic reactions of the raw materials, The volatile composition of the distillates will reflect the raw material used, the technological conditions verified during alcoholic fermentation, and the distillation technique, these being compounds that allow the differentiation of different products and the control of their quality,
| Major Volatile Compounds (mg/L of 100% Volume Alcohol) | Wine Spirit | Grape Marc Spirit | Arbutus Spirit | Honey Spirit | Juniper Flavoured Spirit * | |||||
|---|---|---|---|---|---|---|---|---|---|---|
| Min. | Max. | Min. | Max. | Min. | Max. | Min. | Max. | Min. | Max. | |
| Ethanal | 22.9 | 872.5 | 418.0 | 3549.2 | 180.0 | 580.0 | 31 | 33.6 | 0.0 | 1403.0 |
| ethyl acetate | 64.9 | 1976.7 | 619.1 | 5407.3 | 10,490.0 | 1170.0 | 291.1 | 303.7 | 0.0 | 3565.0 |
| Methanol | 299.0 | 1239.1 | 3394.2 | 23,708.9 | 4870.0 | 8980.0 | 157.9 | 180.9 | 0.0 | 4550.0 |
| 2–Butanol | 0.0 | 266.7 | 0.0 | 233.9 | 0.0 | 0.0 | 0.0 | 0.0 | ||
| 1–Propanol | 157.2 | 482.1 | 281.2 | 804.2 | 110.0 | 250.0 | 360.3 | 372.9 | 0.0 | 545.0 |
| 2-Methyl-1-propanol | 340.9 | 956.3 | 395.2 | 1213.7 | 390.0 | 970.0 | 445.9 | 450.9 | 0.0 | 894.0 |
| 2-Propen-1-ol | 0.0 | 47.7 | 0.0 | 26.1 | 0.0 | 0.0 | 0.0 | 0.0 | ||
| 1–Butanol | 0.0 | 40.8 | 13.7 | 89.3 | 0.0 | 0.0 | 8.2 | 8.8 | 0.0 | 0.0 |
| 2 + 3-Methyl-1-butanol | 1270.3 | 3138.7 | 514.2 | 4814.2 | 940.0 | 1650.0 | 3011.5 | 3118.7 | 55.0 | 5382.0 |
Taking into account the toxicity of methanol, several countries impose maximum limits on their levels in spirit drinks. The results of the determination of methanol, as well as other volatile compounds in spirits, are presented in relation to the ethanol content of the drink, expressed as compound weight per hL or L of 100% volume alcohol).
Likewise, the legal limits established for methanol are expressed in g per hL of pure alcohol, with Table 2 showing the values for the different spirits. In the United States, the allowed methanol concentration for distilled fruit spirits is 7 g/L of 100% volume, In the same line, Australia and New Zealand proposed a limit of 7 g for the spirits,
Since 2008, there have been EU limits on methanol (per liter of 100% vol ethanol) in different distilled spirits, which were recently updated as follows: 13.5 g for some fruit spirits; 10 g for fruit marc spirits, and 2 g, the lowest allowed methanol content, for wine spirits and brandy.
- In the case of honey spirits, there is no limit for methanol content ( Table 2 ).
- Table 3 and Table 4 present the methanol content found in wine spirits and brandies, grape marc spirits, fruit spirits, and honey spirits based on gathering data from several scientific publications.
- Taking into account that the methanol results from enzymatic reactions and the enzymes are present in the raw materials, the majority of the spirits present methanol, as displayed in Table 1, Table 3, and Table 4,
An interesting exception is the honey spirits, which possess null or very low amounts of methanol. In fact, it has been reported that mead contains very low amounts of methanol (maximum of 136.87 g/L of 100% vol. alcohol, Table 1 ), which is expected to increase little when the fermentation is performed in the presence of pollen,
- Bee pollen naturally occurs in honey and may also be added throughout the fermentation process to promote yeasts’ growth.
- The presence of pollen, which contains low amounts of organic matter may explain the very low amounts of methanol that is detected in the honey spirits.
- Several factors have been reported to influence the amount of methanol of the fermented beverages among which: the temperature, the size of the raw material, the content of pectin, and the activity of pectin methylesterase, and the yeast strain involved in the fermentation process,
The content of pectin in bee pollen is residual, which may justify the lower methanol content of honey-based fermented products, in comparison to those developed using fruits. The amount of methanol in these beverages could be also a good fingerprint to detect adulterations.
There are some fruits in which only the pulp is used for alcoholic fermentation and distillation, among these is passion fruit, A similar procedure was used to produce wine spirit and brandies, which can explain their low amounts of methanol ( Table 4 ). On the other hand, some spirits are produced after a fermentation process in the presence of peel and other solid parts of the raw material.
This is the case of grape mark spirit and some fruit spirits such as arbutus spirit and that can explain the high values shown in Table 3 and Table 4, In the development of melon spirits, it is also verified that the use of melon paste as a raw material originated in a spirit with high amounts of methanol ( Table 3 ).
How common is methanol poisoning?
From Wikipedia, the free encyclopedia
| Methanol toxicity | |
|---|---|
| Other names | Methanol poisoning, methanol overdose |
| Molecular structure of methanol | |
| Specialty | Emergency medicine |
| Symptoms | Decreased level of consciousness, poor coordination, vomiting, abdominal pain, specific smell on the breath |
| Complications | Blindness, kidney failure |
| Causes | Methanol (such as found in windshield washer fluid ) |
| Diagnostic method | Blood acidosis, increased osmol gap, methanol blood level |
| Differential diagnosis | Infections, exposure to other toxic alcohols, serotonin syndrome, diabetic ketoacidosis |
| Prevention | Consuming safe alcoholic beverages |
| Treatment | Antidote, hemodialysis |
| Medication | Fomepizole, ethanol |
| Prognosis | Good with early treatment |
| Frequency | 1,700 cases per year (US) |
Methanol toxicity (also methanol poisoning ) is poisoning from methanol, characteristically via ingestion. Symptoms may include a decreased level of consciousness, poor or no coordination, vomiting, abdominal pain, and a specific smell on the breath.
- Decreased vision may start as early as twelve hours after exposure.
- Long-term outcomes may include blindness and kidney failure,
- Blindness may occur after drinking as little as 10 mL; death may occur after drinking quantities over 15 mL (median 100 mL, varies depending on body weight).
- Methanol poisoning most commonly occurs following the drinking of windshield washer fluid,
This may be accidental or as part of an attempted suicide, Toxicity may also rarely occur through extensive skin exposure or breathing in fumes. When methanol is broken down by the body it results in formaldehyde, formic acid, and formate which cause much of the toxicity.
The diagnosis may be suspected when there is acidosis or an increased osmol gap and confirmed by directly measuring blood levels. Other conditions that can produce similar symptoms include infections, exposure to other toxic alcohols, serotonin syndrome, and diabetic ketoacidosis, Early treatment increases the chance of a good outcome.
Treatment consists of stabilizing the person, followed by the use of an antidote, The preferred antidote is fomepizole, with ethanol used if this is not available. Hemodialysis may also be used in those where there is organ damage or a high degree of acidosis,
- Other treatments may include sodium bicarbonate, folate, and thiamine,
- Outbreaks of methanol ingestion have occurred due to contamination of drinking alcohol,
- This is more common in the developing world,
- In 2013 more than 1700 cases occurred in the United States.
- Those affected are usually adult and male.
Toxicity to methanol has been described as early as 1856.
Does drinking alcohol stop methanol poisoning?
If Fomepizole is not available, begin to give the person high doses of ethanol (i.e., whisky, vodka, etc.) immediately. A person’s liver will process ethanol first instead of methanol, delaying the onset of methanol poisoning and allowing for more time to process methanol out of a person’s system.
Can methanol poisoning be detected?
The diagnosis of methanol poisoning is challenging, requiring blood gas analysis and then laboratory-based chromatographic measurement of methanol concentrations. This usually takes hours if at all available in the receiving hospital.
Do all alcoholic drinks contain methanol?
Abstract – Methanol, a potent toxicant in humans, occurs naturally at a low level in most alcoholic beverages without causing harm. However, illicit drinks made from “industrial methylated spirits” can cause severe and even fatal illness. Since documentation of a no-adverse-effect level for methanol is nonexistent in the literature a key question, from the public health perspective, is what is the maximum concentration of methanol in an alcoholic drink that an adult human could consume without risking toxicity due to its methanol content? Published information about methanol-intoxicated patients is reviewed and combined with findings in studies in volunteers given small doses of methanol, as well as occupational exposure limits (OELs), to indicate a tolerable (“safe”) daily dose of methanol in an adult as 2 g and a toxic dose as 8 g.
The simultaneous ingestion of ethanol has no appreciable effect on the proposed “safe” and “toxic” doses when considering exposure over several hours. Thus, assuming that an adult consumes 4 x 25-ml standard measures of a drink containing 40% alcohol by volume over a period of 2 h, the maximum tolerable concentration (MTC) of methanol in such a drink would be 2% (v/v) by volume.
However, this value only allows a safety factor of 4 to cover variation in the volume consumed and for the effects of malnutrition (i.e., folate deficiency), ill health and other personal factors (i.e., ethnicity). In contrast, the current EU general limit for naturally occurring methanol of 10 g methanol/l ethanol provides a greater margin of safety.
Why is methanol added to ethanol?
Ethanol is an important organic compound having large industrial application. It is often misused and hence poisonous gas like methanol is added into it to prevent its misuse as a beverage. The ethanol in which methanol is added is known as denatured spirit.
Does methanol turn into ethanol?
Description –
This application is a continuation-in-part of, and claims priority based on provisional application Ser. No.61/067,403, filed Feb.28, 2008, the contents of which are incorporated by reference in their entirety. This invention relates to the production of ethanol. More particularly, this invention relates to the production of ethanol from methanol. This invention also relates to the production of ethanol from syngas. The syngas may be produced by gasifying biomass. A portion of the carbon monoxide and a portion of the hydrogen contained in the syngas are reacted to produce methanol. The methanol is reacted with carbon monoxide from the syngas to produce methyl acetate, which is reacted with hydrogen, also from the syngas, to produce ethanol. Ethanol is a fuel that is used primarily as a gasoline additive. Blends of ethanol and gasoline, containing between 5% and 85% ethanol, have been commercialized. Ethanol has a higher octane number than gasoline, and it is combusted completely in spark-ignited internal combustion engines. Because ethanol can be derived from renewable biomass, its use in blends of ethanol and gasoline contributes to the reduction of greenhouse gas emissions in the transportation sector. In accordance with an aspect of the present invention, there is provided a process for converting methanol to ethanol. The process comprises reacting methanol and carbon monoxide (such as, for example, a carbon monoxide-rich gas derived from syngas) under conditions to produce a product comprising at least 25 mole % methyl acetate. The methyl acetate then is hydrogenolyzed and hydrogenated using hydrogen (such as, for example, hydrogen which has been separated from syngas) to produce ethanol. In accordance with one non-limiting embodiment, syngas is produced in order to provide all or a portion of the methanol, hydrogen, and CO requirements for the process. The reaction of methanol and carbon monoxide is a carbonylation reaction, which creates a carbon-carbon (C—C) bond, and which may be effected in the presence of a catalyst, which, under appropriate conditions, provides acetic acid and/or methyl acetate. If the reaction of methanol and carbon monoxide is conducted under conditions having a sufficient molar ratio of methanol to carbon monoxide, i.e., a sufficient molar excess of methanol vis-à-vis carbon monoxide, and a sufficient acidity, at least a portion of the formed acetic acid, via catalytic carbonylation, may be esterified rapidly to methyl acetate, thereby producing a reaction product that includes at least 25 mole % methyl acetate. The molar ratio of methyl acetate to acetic acid in the reaction product is a result of the kinetic rate of the acid catalysis following the carbonylation reaction, and it is limited by the equilibrium between the reactants and products. The equilibrium between reactants and products may be altered by changing reaction conditions such as temperature, pressure, and composition of reactants. In a non-limiting embodiment, the methanol and carbon monoxide are reacted at a molar ratio of methanol to carbon monoxide of from about 2 to about 10. In another non-limiting embodiment, the methanol and carbon monoxide are reacted at a molar ratio of from about 2 to about 5. In a non-limiting embodiment, the reaction product includes methyl acetate in an amount of at least 50 mole %. In another non-limiting embodiment, the reaction product includes methyl acetate in an amount greater than 75 mole %. In yet another non-limiting embodiment, the remaining component of the reaction product is essentially acetic acid. In another non-limiting embodiment, the methanol and carbon monoxide are reacted at a temperature of from about 100° C. to about 350° C. In another non-limiting embodiment, the methanol and carbon monoxide are reacted at a temperature of from about 120° C. to about 280° C. In another non-limiting embodiment, the methanol and carbon monoxide are reacted at a temperature of from about 150° C. to about 250° C. In a further non-limiting embodiment, the methanol and carbon monoxide are reacted at a temperature of from about 150° C. to about 200° C. In another non-limiting embodiment, the methanol and carbon monoxide are reacted at a pressure of from about 15 atm to about 100 atm. In another non-limiting embodiment, the methanol and carbon monoxide are reacted at a pressure of from about 15 atm to about 50 atm. In one non-limiting embodiment, the reaction of methanol with carbon monoxide is effected by reacting methanol with a syngas, such as a CO-rich syngas. The methanol and carbon monoxide are reacted in the presence of a suitable catalyst for converting methanol and carbon monoxide to acetic acid and methyl acetate. The reaction of methanol with carbon monoxide may be effected in the liquid phase or in the gas phase. In a non-limiting embodiment, such reaction (carbonylation plus acid catalysis) is effected in the liquid phase. In this case, the reaction, in a non-limiting embodiment, is effected catalytically in the presence of salts of active metals, or in the presence of finely divided and slurried powdered active metals. Such active metals include, but are not limited to, Group VIII metals such as Co, Ni, Pd, Ru, Rh, Re, Os, Ir, and the like. The active metal may be employed in combination with a promoter such as a halide (e.g., bromide, chloride, iodide). In one non-limiting embodiment, the halide is an organic halide, such as a methyl halide. Alternatively, the halide is a metal halide. In another non-limiting embodiment, the promoter is a “green promoter,” such as, for example, a dimethyl carbonate promoter. In another non-limiting embodiment, the active metal may be employed in combination with other additives, such as alkali metals (e.g., Li, Na, K, Rb, Cs), alkaline earth metals (e.g., Ba, Mg, Ca, Sr, Ra), and/or promoter metals such as Mo, Cu, Au, Ag, W, V, Cd, Cr, Zn, Mn, or Sn. The metals may be added to the liquid mixture as soluble inorganic salts, soluble organometallic compounds, or coordination complexes with carbonyls, for example. In an alternative non-limiting embodiment, the metals are added as finely divided powders which then are slurried in the reaction mixture. In yet another non-limiting embodiment, the reaction of methanol with carbon monoxide is effected in the gas phase. When the reaction is effected in the gas phase, the reaction, in a non-limiting embodiment, is effected in the presence of a catalyst, which may be a solid catalyst. Suitable catalysts include, but are not limited to, supported heterogeneous metals on matrices such as activated carbon, silica, alumina, chromite, zirconia, and other stable oxides at reaction conditions, such as iron oxide, molybdenum oxide, and the like. In another non-limiting embodiment, the catalyst is a sulfided catalyst, such as sulfided Co or sulfided Mo. In another non-limiting embodiment, the support is an acidic support, such as an alumina support. Metal catalysts which may be employed include, but are not limited to, the metals which may be employed in carrying out the reaction in the liquid phase. As noted hereinabove, depending upon the conditions under which the methanol is reacted with the carbon monoxide, acetic acid may be present in the reaction product produced as a result of reacting the methanol and carbon monoxide. Thus, in another non-limiting embodiment, methanol and carbon monoxide are reacted under conditions to produce a product comprising at least 25 mole % methyl acetate and the remainder of the reaction product is essentially acetic acid. The acetic acid is reacted with at least one alcohol to produce at least one acetate. Thereafter, the “initial” methyl acetate, i.e., the methyl acetate produced as a result of reacting methanol with carbon monoxide, and the at least one acetate produced by reacting the acetic acid with the at least one alcohol, are hydrogenolyzed and hydrogenated to produce ethanol. As used herein, the term “hydrogenolysis” means the rupture of the ester bond in the presence of hydrogen, and the term “hydrogenation” means the addition of hydrogen to the moieties produced by the hydrogenolysis. In another non-limiting embodiment, the acetic acid, when produced by reacting carbon monoxide with methanol as hereinabove described, is reacted with the at least one alcohol at a temperature of from about 80° C. to about 250° C. In another non-limiting embodiment, the acetic acid is reacted with the at least one alcohol at a temperature of from about 80° C. to about 150° C. In a further non-limiting embodiment, the acetic acid is reacted with the at least one alcohol at a temperature of from about 80° C. to about 120° C. In yet another non-limiting embodiment, the acetic acid is reacted with the at least one alcohol at a pressure of from about 1 atm to about 20 atm. In a further non-limiting embodiment, the acetic acid is reacted with the at least one alcohol at a pressure of from about 1 atm to about 10 atm. In a non-limiting embodiment, the at least one alcohol has 1 to 6 carbon atoms. In another non-limiting embodiment, the at least one alcohol is ethanol, and ethyl acetate is produced by reacting the acetic acid with ethanol. In another non-limiting embodiment, the at least one alcohol is methanol, and methyl acetate is produced by reacting the acetic acid with methanol. In another non-limiting embodiment, the at least one alcohol is butanol, and butyl acetate is produced by reacting the acetic acid with butanol. In yet another non-limiting embodiment, the acetic acid is reacted with methanol and ethanol to produce methyl acetate and ethyl acetate. In still another non-limiting embodiment, the acetic acid is reacted with methanol and butanol to produce methyl acetate and butyl acetate. In a further non-limiting embodiment, the acetic acid is reacted with methanol, ethanol, and butanol to produce methyl acetate, ethyl acetate, and butyl acetate. In yet another non-limiting embodiment, the acetic acid and the at least one alcohol are reacted in the liquid phase (maintained by a suitable choice of temperature and pressure) in the presence of a suitable catalyst. Such catalysts include, but are not limited to, protonated zeolite catalysts, sulfuric acid, phosphoric acid, and protonated ionic exchange resins. In another non-limiting embodiment, the acetic acid and the at least one alcohol are reacted in the gas phase in the presence of a suitable solid catalyst. Suitable catalysts include, but are not limited to, alumina, silica-alumina, protonated zeolites, and protonated ionic exchange resins. In another non-limiting embodiment, the methyl acetate produced by reacting methanol and carbon monoxide (i.e., the “initial methyl acetate”), and, in cases where acetic acid also was produced by reacting methanol and carbon monoxide, the at least one acetate produced by reacting acetic acid with at least one alcohol, are reacted with the hydrogen at a temperature of from about 150° C. to about 300° C. to produce a reaction product which includes ethanol. In another non-limiting embodiment, the initial methyl acetate and the at least one acetate (if produced) are reacted with the hydrogen at a temperature of from about 170° C. to about 250° C. In yet another non-limiting embodiment, the initial methyl acetate and the at least one acetate (if produced) are reacted with hydrogen at a pressure of from about 10 atm to about 100 atm. In a further non-limiting embodiment, the initial methyl acetate and the at least one acetate (if produced) are reacted with the hydrogen at a pressure of from about 20 atm to about 60 atm. In another non-limiting embodiment, the initial methyl acetate and the at least one acetate (if produced) are reacted with hydrogen at a molar ratio of hydrogen to acetate of at least 3. In one non-limiting embodiment, the reaction of the initial methyl acetate and the at least one acetate (if produced) with hydrogen is effected by reacting the initial methyl acetate and the at least one acetate (if produced) with a syngas, such as an H 2 -rich syngas. In another non-limiting embodiment, the initial methyl acetate and the at least one acetate (if produced) are reacted with hydrogen in the presence of a hydrogenation catalyst. Representative examples of hydrogenation catalysts which may be employed include, but are not limited to, Cu/Cr 2 O 3, Cu/ZnO/Al 2 O 3, Cu/Al 2 O 3, Cu/carbon, and combinations of Cu/Zn/Fe and Cu/Zn/Fe/Co on appropriate catalyst supports. In another non-limiting embodiment, one or both of the carbon monoxide and hydrogen that are employed in the process of the present invention is obtained from synthesis gas, or syngas. In yet another non-limiting embodiment, each of the carbon monoxide and hydrogen is obtained from syngas. In a further non-limiting embodiment, a portion of the carbon monoxide and a portion of the hydrogen obtained from the syngas are reacted to produce methanol, which is employed in the process of the present invention. Thus, in accordance with another aspect of the present invention, there is provided a process for producing ethanol from synthesis gas. The synthesis gas comprises carbon monoxide and hydrogen, and may be produced by methods known to those skilled in the art, such as, for example, those disclosed in PCT Application No. WO00/69994. A portion of the carbon monoxide and a portion of the hydrogen from the synthesis gas are reacted to produce methanol. The methanol then is reacted with another portion of the carbon monoxide from the syngas, under conditions hereinabove described, to produce a product comprising at least 25 mole % methyl acetate. As noted hereinabove, the product may further include acetic acid. If acetic acid is present in the product, such acetic acid is reacted with at least one alcohol under conditions hereinabove described to product at least one acetate. The methyl acetate produced by reacting methanol with carbon monoxide (i.e., the “initial methyl acetate”), and the at least one acetate (if present) formed by reacting acetic acid with at least one alcohol, then are hydrogenated with another portion of the hydrogen from the syngas, under conditions hereinabove described, to produce ethanol. In a non-limiting embodiment, the syngas is obtained by gasifying carbonaceous materials such as polyethylene and polypropylene residues, rubber residues, and biomass such as biological treatment sludge, forest biomass, agricultural biomass, and urban biomass. Examples of the gasification of such carbonaceous materials are disclosed in PCT Application No. WO00/69994, the contents of which are incorporated herein by reference. When urban biomass is employed, such urban biomass may be obtained from municipal solid waste following sorting, drying (biologically or thermally using low grade heat from the gasification process), and size reduction. The crude synthesis gas produced by the gasification of biomass is conditioned such that impurities are reduced to a level that permits the catalytic synthesis of methanol wherein said catalyst may be on stream for at least 5,000 hours before regeneration. In a non-limiting embodiment, the methanol synthesis is effected at a H 2 :CO ratio of from about 1:1 to about 3:1. In another non-limiting embodiment, the methanol synthesis is effected under conditions such that CO is converted to methanol at a rate of up to 50 mole %. The unconverted syngas then is separated from the methanol and passed through a membrane whereby the syngas is fractionated into a CO-rich portion and a hydrogen-rich portion. In a non-limiting embodiment, the syngas is passed through a commercially available hollow-fiber membrane. Examples of hollow-fiber membranes which may be employed include, but are not limited to, PRISM™, POLYSEP™ VAPORSEP™, or other separation systems which provide for a permeate rich in H 2 and a retentate rich in CO. In another non-limiting embodiment, the syngas is passed through the membrane at a temperature which does not exceed 150° C., and at a pressure which does not exceed 30 atm. Hydrogen permeates the membrane while a CO-rich gas does not permeate the membrane. The CO-rich gas, which does not pass through the membrane, may contain CO 2 in an amount that does not exceed 15 mole %, and hydrogen in an amount that does not exceed 5 mole %. Such CO-rich gas is reacted with methanol under conditions to provide a product comprising methyl acetate in an amount of at least 25 mole %. Acetic acid also may be produced. The recovered pure hydrogen, which permeates the membrane, may be used downstream for the hydrogenolysis/hydrogenation of methyl acetate produced as a result of the reaction of methanol with carbon monoxide. If, in addition to methyl acetate, the reaction of methanol with carbon monoxide also produces acetic acid, the acetic acid is reacted with at least one alcohol to produce at least one acetate. Such at least one acetate and the initial methyl acetate are reacted with the recovered pure hydrogen to produce ethanol. In another non-limiting embodiment, the syngas, which has been conditioned to have a H 2 :CO molar ratio of from 1:1 to 3:1, and includes CO 2 in an amount which does not exceed 15 mole %, methane in an amount that does not exceed 5 mole %, and water vapor in an amount that does not exceed 5 mole %, is reacted in the presence of a methanol synthesis catalyst, such as, for example, a Cu/ZuO/Al 2 O 3 catalyst dispersed in an inert oil to provide methanol, as well as residual carbon monoxide and hydrogen. The methanol then is reacted with the residual carbon monoxide from the syngas. In one embodiment, the residual carbon monoxide and hydrogen from the syngas, are passed through a series of selective membranes such as those hereinabove described, in order to provide a hydrogen-rich portion and a carbon-monoxide-rich portion, as hereinabove described. The carbon-monoxide-rich portion then is reacted with the methanol in the presence of a catalyst, to produce a product comprising methyl acetate (i.e., the “initial methyl acetate”) in an amount of at least 25 mole % and also may produce acetic acid. In a non-limiting embodiment, the methanol and carbon monoxide are reacted in a liquid phase reactor. The methanol is reacted with the carbon monoxide at a temperature of from about 150° C. to about 200° C., and a pressure of from about 15 atm to about 50 atm. The acetic acid (if produced) then is esterified to ethyl acetate and/or methyl acetate and/or butyl acetate by reacting the acetic acid with methanol and/or ethanol and/or butanol in the presence of an acid catalyst, such as those hereinabove described. The acetic acid is reacted with the methanol and/or ethanol and/or butanol at a temperature of from about 80° C. to about 250° C., and a pressure of from about 1 atm to about 20 atm. When reacted with ethanol, the acetic acid is converted to ethyl acetate. When reacted with methanol, the acetic acid is converted to methyl acetate. When reacted with butanol, the acetic acid is converted to butyl acetate. The at least one acetate (if produced), which may be ethyl acetate, methyl acetate, or butyl acetate, or a combination of methyl acetate and/or ethyl acetate and/or butyl acetate, and the initial methyl acetate then are reacted with the residual hydrogen, recovered from the separation of carbon monoxide and hydrogen from the syngas, in the presence of a hydrogenation catalyst to produce ethanol, as well as methanol. When the at least one acetate (when produced) is butyl acetate, or a combination of methyl acetate and butyl acetate, butanol also is produced. The initial methyl acetate and the at least one acetate (if present) are reacted with hydrogen at a temperature of from about 150° C. to about 300° C. and at a pressure of from about 10 atm to about 100 atm. The methanol that is produced as a result of reacting the methyl acetate with hydrogen, in a non-limiting embodiment, is recycled such that it is reacted with the carbon monoxide obtained from the syngas to provide a reaction product comprising at least 25 mole % methyl acetate. In another non-limiting embodiment, when acetic acid is included in such reaction product, a portion of the methanol also is recycled such that it is reacted with the acetic acid to produce methyl acetate. Likewise, in non-limiting embodiments, a portion of the ethanol, and/or butanol (when produced), may be recycled such that they are reacted with acetic acid to produce ethyl acetate and/or butyl acetate. As noted hereinabove, methanol that is produced as a result of reacting methyl acetate with hydrogen can be recycled such that it is reacted with the carbon monoxide obtained from the syngas to provide methyl acetate, and with acetic acid when acetic acid also is produced, also to provide methyl acetate. Thus, in a non-limiting embodiment of the process of the present invention, the conversion of acetic acid to methyl acetate may be effected by use of an initial “start-up” quantity of methanol that is produced by reacting a portion of the hydrogen in the syngas to produce methanol. A portion of the methanol is reacted as hereinabove described to convert acetic acid to methyl acetate, which is hydrogenated to produce methanol and ethanol. The methanol thus produced, then is recycled and supplies the portion of methanol requirements for converting acetic acid to methyl acetate either during reaction between methanol and CO or in a separate step for converting acetic acid to methyl acetate. Thus, in one non-limiting embodiment, the present invention provides a method of producing ethanol from biomass. Such method is effected by gasifying the biomass to produce syngas, which includes carbon monoxide and hydrogen. The carbon monoxide and hydrogen in the syngas are reacted to produce methanol. Unconverted syngas then is separated from the methanol and fractionated into a CO-rich portion and a hydrogen-rich portion. The CO-rich portion then is reacted with the methanol to produce a product comprising at least 25 mole % methyl acetate, and, in some cases, acetic acid. The methyl acetate then is reacted with the hydrogen-rich portion of the syngas to produce ethanol and methanol. The methanol produced in this reaction is recycled to be reacted with the CO-rich portion of the syngas to produce methyl acetate, or, when any acetic acid is produced, may be reacted with such acetic acid to produce additional methyl acetate, which then is reacted with the hydrogen-rich portion of the syngas to produce ethanol and methanol. The invention now will be described with respect to the following examples; it is to be understood, however, that the scope of the present invention is not intended to be limited thereby. EXAMPLE 1 The carbonylation of methanol with carbon monoxide is carried out in the liquid phase using a custom made (250 mL internal volume) SS 316 autoclave. The autoclave is heated with a salt bath (a eutectic mixture of nitrates and nitrites) whose temperature is controlled by an electrical heating system. Uniform temperature is maintained in the autoclave walls by the salt bath. Agitation of the liquid in the autoclave is made by a sparger-dispersor through which mixtures of gas (N 2, pure CO or CO-rich syngas) and vapors (of the volatile organics) are blown into the autoclave and bubbled through the liquid. The disperser produces fine bubbles which maintain homogeneous agitation inside the liquid phase. The ensemble acts as a mini-bubbling column reactor. The autoclave has an exit port that sends the gas/vapor mixture to a reflux condenser operating at the same pressure as the autoclave. The reflux condenser is thermostated by a fluid circulating through a jacket and an internal coil. After the reflux condenser there is a backpressure regulator system that allows the pressure to drop to a desired level (1-40 atm). A final condensing system coupled with a chilled fluid (<15° C.) allows the condensed vapors to be recovered. The uncondensed gas is collected in a Teflon bag (initially purged) and analyzed. The initial charge, which occupies ⅔ of the autoclave internal volume is comprised of RfCl 3,3H 2 O or RhI 3 (in both cases the Rh concentration is in the range from 3 to 5×10 −3 M), iodide salt (LiI and NaI are used at 0.5-0.75 M), water (1.0-5.0 M) and acetic acid (its molar concentration accounts for the difference). The autoclave is flashed repeatedly with N 2 prior to and after introducing the charge. Thus at time zero the autoclave has the charge plus inert N 2 at a pressure slightly above atmospheric. The autoclave then is heated to reaction temperature which is varied from 170 to 200C. Methanol, methyl iodide, and methyl acetate are pumped via independent pumping systems (with refrigerated heads) into a thermostated (<15° C.) static mixing system. Methyl acetate is added at molar ratios relative to methanol that do not exceed 1:10. Methyl iodide is added to maintain an iodide concentration in the liquid phase ranging from 0.1 to 2.0 M. From the static mixing system the uniform liquid mixture is sent to a small reservoir from where it is pumped under pressure through a heat exchanger. The vaporized mixture is directed to a second static mixer where it mixes with the reactive gas (CO-rich gas ranging from pure CO to a mixture of CO as the main gas with CO 2, up to 10 vol. %, light hydrocarbons up to 10 vol. %, and hydrogen, up to 2 vol. %). The pressure can be controlled so that the pressure in the autoclave is between 20 and 50 atm. The temperature is varied from 170 to 200° C. The gas/vapor mixture moves into the autoclave through an appropriate valving system and bubbles through the liquid. The controlled flow rate dictates the hourly space velocities which range between 10 and 100 mole MeOH liter −1 h −1, The CO used in these experiments is present at a molar ratio with respect to MeOH that ranges from 0.1 to 0.5 because the desired product is the acetate and not the acetic acid. CO is converted to a mixture of methyl acetate and acetic acid (molar ratio of 3:1, methyl acetate to acetic acid). The acetic acid can be converted further to the acetate in a separate reactor. EXAMPLE 2 The carbonylation of methanol with carbon monoxide is carried out in the liquid phase using the custom made (250 mL internal volume) SS 316 autoclave described in the preceding example. The autoclave is heated with a salt bath (a eutectic mixture of nitrates and nitrites) whose temperature is controlled by an electrical heating system. Uniform temperature is maintained in the autoclave walls by the salt bath. Agitation of the liquid in the autoclave is made by a sparger-dispersor through which mixtures of gas (N 2, pure CO or CO-rich syngas) and vapors (of the volatile organics) are blown into the autoclave and bubbled through the liquid. The dispersor produces fine bubbles which maintain homogeneous agitation inside the liquid phase. The ensemble acts as a mini-bubbling column reactor. The autoclave has an exit port that sends the gas/vapor mixture to a reflux condenser operating at the same pressure as the autoclave. The reflux condenser is thermostated by a fluid circulating through a jacket and an internal coil. After the reflux condenser there is a backpressure regulator system that allows the pressure to drop to a desired level (1-40 atm). A final condensing system coupled with a chilled fluid (<15° C.) allows the condensed vapors to be recovered. The uncondensed gas is collected in a Teflon bag (initially purged) and analyzed. The initial charge, which occupies ⅔ of the autoclave internal volume is comprised of soluble non-halide Rh salts (the Rh concentration is in the range from 3 to 5×10 −3 M), carbonate salts (Li and Na are used at 0.5-0.75 M), water (1.0-5.0 M) and acetic acid (its molar concentration accounts for the difference). The autoclave is flashed repeatedly with N 2 prior to and after introducing the charge. Thus at time zero the autoclave has the charge plus inert N 2 at a pressure slightly above atmospheric. The autoclave then is heated to reaction temperature which is varied from 170° to 200° C. Methanol, dimethyl carbonate (which can be obtained by reacting produced methanol and separated carbon dioxide in a separate reactor), and methyl acetate are pumped via independent pumping systems (with refrigerated heads) into a thermostated (<15° C.) static mixing system. Methyl acetate is added at molar ratios relative to methanol that do not exceed 1:10. Dimethyl carbonate is added to maintain a carbonate concentration in the liquid phase ranging from 0.1 to 2.0 M. From the static mixing system the uniform liquid mixture is sent to a small reservoir from where it is pumped under pressure through a heat exchanger. The vaporized mixture is directed to a second static mixer where it mixes with the reactive gas (CO-rich gas ranging from pure CO to a mixture of CO as the main gas with CO 2, up to 10 vol. %, light hydrocarbons up to 10 vol. %, and hydrogen, up to 2 vol. %). The pressure can be controlled so that the pressure in the autoclave is between 20 and 50 atm. The temperature is varied from 17-° to 200° C. The gas/vapor mixture moves into the autoclave through an appropriate valving system and bubbles through the liquid. The controlled flow rate dictates the hourly space velocities which range between 10 and 100 mole MeOH liter −1 h −1, The CO used in these experiments is present at a molar ratio with respect to MeOH that ranges from 0.1 to 0.5 because the desired product is the acetate and not the acetic acid. CO is converted to a mixture of methyl acetate and acetic acid (molar ratio of 3:1, methyl acetate to acetic acid). The acetic acid can be converted further to the acetate in a separate reactor. EXAMPLE 3 A gas/vapor set of experiments is carried out using a fixed bed reactor in which two types of catalysts are tested: Rh on carbon and on alumina, and Ir also on both carbon and alumina. Impregnation of the supports is made to provide 0.5-1.0 wt % of metal on the support. The supports also are impregnated with alkali or alkali iodide at molar ratios of 2 to 5 with respect to the metal impregnated previously. Calcination followed at 350° C. The reactor was an SS 316 15.875 mm internal diameter (i.d.) reactor lined with a thin (1 mm) sheet of pure copper. The catalyst is placed between two zones filled with carborundum grains (previously deionized). The catalyst bed has a length of 25 cm and the catalyst is mixed on a 50/50 wt basis with the same carborundum used in the upper and lower zones holding the catalyst zone. Methanol and pure CO or CO-rich syngas of the same composition shown in Example 1 are added as a vapor/gas mixture prepared by the same system also described in Example 1. The methanol to CO molar ratio is between 1 and 5, whereas the methyl iodide added to the methanol is maintained at a molar ratio between 0.05 and 0.25, relative to the methanol. Reaction conditions are such that the GHSV, based on CO passed through the catalytic bed, varies between 2000 and 10000 h −1, After being blown through the catalytic bed at a temperature from 175 to 300° C., and a pressure from 10 to 50 atm, it is found that the CO is converted at a rate near 100% when the methanol: CO molar ratio is >2. The selectivity varies as a function of temperature and pressure. It is found that within a wide range (200-240° C., 15-50 atm) for the specified GHSV range one obtains a molar selectivity of 50-75% acetate and 25-50% acetic acid. EXAMPLE 4 A second gas/vapor set of experiments is carried out using a fixed bed reactor in which the two types of catalysts above described are tested: Rh on carbon and on alumina, and Ir also on both carbon and alumina. Impregnation of the supports is made from non-halide salts to provide 0.5-1.0 wt % of metal on the support. The supports also are impregnated with alkali at molar ratios of 2 to 5 with respect to the metal impregnated previously. Calcination followed at 350° C. The reactor was an SS 316 15.875 mm internal diameter (i.d.) reactor lined with a thin (1 mm) sheet of pure copper. The catalyst is placed between two zones filled with carborundum grains (previously deionized). The catalyst bed has a length of 25 cm and the catalyst is mixed on a 50/50 wt basis with the same carborundum used in the upper and lower zones holding the catalyst zone. Methanol and pure CO or CO-rich syngas of the same composition shown in Example 1 are added as a vapor/gas mixture prepared by the same system also described in Example 1. The methanol to CO molar ratio is between 1 and 5, whereas the dimethyl carbonate (which can be obtained by reacting produced methanol and separated carbon dioxide in a separate reactor) added to the methanol is maintained at a molar ratio between 0.05 and 0.25, relative to the methanol. Reaction conditions are such that the GHSV, based on CO passed through the catalytic bed, varies between 2,000 and 10,000 h −1, After being blown through the catalytic bed at a temperature from 175 to 300° C., and a pressure from 10 to 50 atm, it is found that the CO is converted at a rate near 100% when the methanol: CO molar ratio is greater than 2. The selectivity varies as a function of temperature and pressure. It is found that within a wide range (200-240° C., 15-50 atm) for the specified GHSV range one obtains a molar selectivity of 50-75% acetate and 25-50% acetic acid. EXAMPLE 5 Acetic acid (1500 mL or 25 gmoles) produced in accordance with Examples 1 or 3, in liquid form is placed in a 5000 mL vessel acting as a reboiler. Above the vessel there is an insulated packed distillation column (acting as an enriching section). The top of the distillation column is linked to a reflux condenser that is operated at a temperature of about 70° C. The vessel is heated externally to a temperature of from 95° C. to 105° C. at a pressure of 1 atm. Phosphoric acid is added to the acetic acid in an amount of from 1 wt % to 5 wt %, of the weight of the acetic acid. Ethanol, placed in a 2000 mL vessel, is entrained by bubbling nitrogen through the vessel, which is maintained at a temperature not exceeding 50° C. The nitrogen-entrained alcohol is bubbled through the acetic acid/phosphoric acid mixture. Bubbling rates are adjusted in the 0.01-10 mole alcohol/min range. Bubbling is facilitated by a diffuser. Reflux is generated internally by the condensed liquid. The column has a packing height that is from 0.2 to 0.5 m. The operation is carried out in such mode that an azeotrope mixture (composition verified by chromatography) of 83 mole % ethyl acetate, 9 mole % ethanol and 5 mole % water vapor leaves the condenser at 70° C. and is subjected to cooling to 20° C. Two phases then are obtained: an upper organic phase and a bottom phase containing most of the water and ethanol. The organic phase is redistilled to produce a small amount of azeotrope (light phase) and essentially pure ethyl acetate (heavy phase). The conversion of incoming ethanol is dictated by the azeotrope equilibrium limit, essentially 90% within a wide range of contact times (corresponding to the different bubbling rates). Unconverted ethanol, dissolved with water in the bottom phase obtained after cooling to 20° C., is dehydrated and recycled to the system. The small amount of azeotrope resulting from the second distillation is returned to the system as such. EXAMPLE 6 A mixture of methanol and acetic acid, produced in accordance with Example 1 or Example 3, having a molar ratio of 1:5 (methanol to acetic acid) is pumped through a heat exchanger that vaporizes the totality of the liquid at 1 atm using a shell and tube heat exchanger which brings the mixture temperature in the range of 125 to 175° C. A small amount of nitrogen also is bled into the heat exchanger. The heated N 2 and vapor mixture, containing less than 10 vol. % N 2, then is blown through a catalytic bed containing either alumina or a protonated zeolite of a suitable pore diameter. The LHSV (liquid hourly space velocity, defined as liters/h of liquid mixture at 25° C. passed through a given volume, in liters of packed catalyst) is between 1 and 5 h −1, The fixed bed reactor is maintained at isothermal conditions within the range of 125 to 175° C. The vapors leaving the reactor are condensed at 25° C. and cooled further to less than 15° C. Samples of the liquid thus recovered are analyzed chromatographically. Only traces of methanol are found. The methanol is converted totally to methyl acetate within the range of conditions used. EXAMPLE 7 The reaction of Example 6 is carried out as hereinabove described except that the molar ratio of methanol to acetic acid is 5:1. The product contains no acetic acid. Methanol, methyl acetate (corresponding to full conversion of the acetic acid) and water are the only products detected at measurable levels. EXAMPLE 8 Methyl acetate produced in accordance with Examples 6 or 7, and maintained as a liquid at 20° C., is pumped at a pressure from 10 to 50 atm, through a heat exchanger that vaporizes it completely at a temperature from 150 to 225° C. Preheated hydrogen at the same temperature range is added to the vapors at their exit from the heat exchanger. The molar ratio H 2 to methyl acetate is from 5 to 10. The hot mixture is blown through a catalytic bed where a CuO/Cr 2 O 3, a CuO/ZnO/Al 2 O 3, or a CuO/ZnO/activated carbon catalyst are placed together with an inert solid which acts as diluent of the catalyst. The CuO is reduced with H 2 /N 2 mixtures prior to adding any acetate. The CuO is thus reduced to Cu, the active form in the hydrogenolysis reaction. The reduction is carried out until no water is produced. The exothermicity of the reduction of the CuO is controlled by keeping the H 2 concentration in the gas mixture at levels not exceeding 5 vol.%. Liquid hourly space velocities (LHSV) are from 1 to 10 h −1 relative to the methyl acetate flow rates and to the true volume occupied by the catalyst (with no inert solid present). The conversion of 1 mole of methyl acetate into 0.90 mole of methanol and 0.90 mole of ethanol is carried out within the ranges of operating parameters considered. The amount of unconverted methyl acetate is 0.10 mole. EXAMPLE 9 Ethyl acetate, produced in accordance with Example 5, and maintained as a liquid at 20° C., is pumped at a pressure from 10 to 50 atm, through a heat exchanger that vaporizes it completely at a temperature from 150 to 225° C. Pretreated hydrogen in the same temperature range is added to the vapors at their exit from the heat exchanger. The molar ratio of H 2 to ethyl acetate is from 5 to 10. The hot mixture is blown through a three phase reactor where a powdered (0.1-0.5 mm) CuO/ZnO/Al 2 O 3 or a CuO/ZnO/activated carbon solid catalyst is suspended (at 20 and 30 wt % solids) in an inert mineral oil. The CuO is reduced with H 2 /N 2 mixtures prior to adding any acetate. The CuO is thus reduced to Cu, the active form in the hydrogenolysis reaction. The reduction is carried out until no water is produced. The exothermicity of the reduction of the CuO is controlled by keeping the H 2 concentration in the gas mixture at levels not exceeding 5 vol.%. Gas hourly space velocities (GHSV, at 15° C. and 1 atm) based on H 2, are between 1000 and 10000 h −1, The conversion of 1 mole of ethyl acetate into 1.90 moles of ethanol is carried out within the ranges of operating parameters considered. The amount of unconverted ethyl acetate is 0.05 mole. EXAMPLE 10 Methyl acetate is converted to methanol and ethanol as described in Example 8, or ethyl acetate is converted to ethanol as described in Example 9, except that the methyl acetate or ethyl acetate is reacted with syngas containing H 2, CO, CO 2, and light hydrocarbons such as methane. The molar ratio of H 2 :CO is varied from 1 to 3. The CO 2 in the syngas does not exceed 10 mole %, and the light hydrocarbons in the syngas do not exceed 10 mole %. The total pressure is varied from 30 atm to 100 atm.90 molar % conversion of methyl acetate to methanol and ethanol, and 95 molar % conversion of ethyl acetate to ethanol are observed. The disclosures of all patents and publications, including published patent applications, are hereby incorporated by reference to the same extent as if each patent or publication were individually and specifically incorporated by reference. It is to be understood, however, that the scope of the present invention is not to be limited to the specific embodiments described above. The invention may be practiced other than as particularly described and still be within the scope of the accompanying claims.
Is methanol a naturally occurring alcohol?
Methanol Methanol, an alcohol with an odor similar to that of ethanol, has been described to exist in low concentrations in the human organism and occurs naturally at a low level in most spirits, without conferring health risk if it exists within the legal limits.
