Industrial solvents methanol

There are two commercial solvent crystaUi2ation processes. The Emersol Process, patented in 1942 by Emery Industries, uses methanol as solvent and the Armour-Texaco Process, patented in 1948, uses acetone as solvent. The fatty acids to be separated are dissolved in the solvent and cooled, usually in a double-pipe chiller. Internal scrapers rotating at low rpm remove the crystals from the chilled surface. The slurry is then separated by means of a rotary vacuum filter. The filter cake is sprayed with cold solvent to remove free Hquid acids, and the solvents are removed by flash evaporation and steam stripping and recovered for reuse (10). 

In the chemical industry, simple aldehydes and ketones are produced in large quantities for use as solvents and as starting materials to prepare a host of other compounds. For example, more than 1.9 million tons per year of formaldehyde, H2C=0, is produced in the United States for use in building insulation materials and in the adhesive resins that bind particle hoard and plywood. Acetone, (CH.3)2C"0, is widely used as an industrial solvent approximately 1.2 million tons per year is produced in the United States. Formaldehyde is synthesized industrial ) by catalytic oxidation of methanol, and one method of acetone preparation involves oxidation of 2-propanol. 

Figure 1 shows how acid-gas-bearing process gases can be generally treated in industrial processes. The sulfur compounds and CO2 may be absorbed in a liquid medium, such as amines, alkali salts (NaOH, K2CO3), physical solvents (methanol, propylene carbonate), or water (3). The absorbed acid gases are released by reduction of pressure and/or by application of heat. Alternatively, the H2S and CO2 may chemically combine with the absorbent (as in NaOH scrubbing) to form salts which are removed in a liquid treatment unit. This requires continual and expensive makeup of sodium to the system. 

The use of solvents in the chemical industry and in the chemical-related industries is ubiquitous. Beyond chemical industries, solvent use has become an integral part of life in the twenty-first century. In 1991, the production of the 25 most commonly used solvents was more than 26 million tons per year. According to EPCRA section 313 data, of the chemicals and chemical categories tracked by the program in 1994, five of the top 10 chemicals released or disposed of were solvents, and included methanol, toluene, xylene, methyl ethyl ketone, and dichloromethane. The total quantity of these chemicals released or disposed of was over 687 million pounds, which accounts for 27% of the total quantity of TRl-listed chemicals released and disposed of in that year (Sullivan, 1997). 

Other alcohols related to ethanol have wide applications as industrial solvents and occasionally cause severe poisoning. Of these, methanol and ethylene glycol are two of the most common causes of intoxication. 

CO + 2 H2 CH3OH ZnO and Cr203 Industrial synthesis of methanol CH3OH Manufacture of plastics, adhesives, gasoline additives industrial solvent... 

Methanol is an industrial solvent, a precursor to additives in unleaded gasolines, and a starting material for the manufacture of formaldehyde, CH20, used in making plastics. Annual U.S. production of methanol, about 1.7 billion gallons, consumes about 700,000 tons of hydrogen. 

Alcohols are some of the most common organic compounds. Methyl alcohol (methanol), also known as wood alcohol, is used as an industrial solvent and as an automotive racing fuel. Ethyl alcohol (ethanol) is sometimes called grain alcohol because it is produced by the fermentation of grain or almost any other organic material. Isopropyl alcohol is the common name for propan-2-ol, used as rubbing alcohol. ... 

Methanol is one of the most common industrial solvents. It is cheap, relatively less toxic (compared with halogenated solvents), and it dissolves a wide variety of polar and nonpolar substances. Methanol is also a starting material for a wide variety of methyl ethers, methyl esters, and other compounds used in plastics, medicines, fuels, and solvents. 

Methanol, CH3OH, is water soluble. Meths is an industrial solvent mixture of ethanol and methanol. It often contains a purple dye and an additive to make it unpalatable to drink. Methanol is poisonous (one spoonful of neat methanol can kill). It can produce similar physiological symptoms to ethanol if consumed in very small quantities in diluted form. It has the additional hazard that it sends people blind and insane and can become addictive. 

In particular, methyl soyate (the biodiesel formed from soybean oil and methanol) is finding industrial applications including cleaning and degreasing technologies (Table 5.5). In industry, solvents are needed to dissolve a material for its removal or transport and then are often evaporated to restore the original material. Therefore, two important parameters are solvent power and evaporation rate. One way to measure solvent power is the kauri-butanol value (KBV), which is a measure of the solubility of kauri gum in the solvent. A high... 

The industrial capacity for worldwide production of methanol in 1994 was 2.42 x 10 metric tons per year3 about 85% of which was used as a starting material in the production of other chemicals or as a solvent. Methanol is used as a raw material in the manufacture of formaldehyde. acetic acid, methyl /erf-butyl ether (MTBE), dimethyl terephthalate, methyl chloride, methyl amines, and many other chemicals. It can also be used as a clean-burning fuel. 

Ingestion of methanol (or methyl alcohol) has been reported among alcoholics, following exposure to industrial solvents [88], and in counterfeit or bootleg wood alcohol poisoning outbreaks [89]. Poisoning may infrequently follow inhalation or skin absorption. Methanol absorption from an empty stomach follows... 

On the shelves of drugstores you can find bottles of ethanol labeled denatured alcohol. Denatured alcohol is ethanol to which small amounts of noxious materials such as aviation gasoline or other organic solvents have been added. Ethanol is denatured in order to make it unfit to drink. Because of their polar hydroxyl groups, alcohols make good solvents for other polar organic substances. For example, methanol, the smallest alcohol, is a common industrial solvent found in some paint strippers, and 2-butanol is found in some stains and varnishes, as shown in Figure 23-5. Perform the CHEMLAB at the end of this chapter to learn about some other properties of small-chain alcohols. 

Oxidation-reduction reactions Many organic compounds can be converted to other compounds by oxidation and reduction reactions. For example, suppose that you wish to convert methane, the main constituent of natural gas, to methanol, a common industrial solvent and raw material for making formaldehyde and methyl esters. The conversion of methane to methanol may be represented by the following equation, in which [O] represents oxygen from an agent such as copper(II) oxide, potassium dichromate, or sulfuric acid. 

The destruction of hazardous chemical wastes by oxidation in supercritical water is a promising new technology which has several advantages over conventional methods of toxic chemical waste disposal. Although the feasibility of the supercritical water oxidation process has been demonstrated, there is little kinetic information available on the underlying reaction mechanisms. We have recently determined the oxidation kinetics of several model compounds in supercritical water, and now report on our results of the oxidation of methanol, a conunon industrial solvent, in supercritical water. Globd kinetic expressions are presented and our attempts to model the reaction using a free-radical mechanism with 56 elementary reactions are discussed. The inability of the elementary reaction model to represent oxidation in supercritical water is demonstrated and future model modifications are discussed. 

The low polarity of carbon dioxide appears as a limitation to its use in extraction technologies requiring a total lipid extract, because more polar lipids cannot be extracted. Many of the extraction protocols used for these applications rely on a modified solvent system based on the addition of small volumes of a polar organic solvent (methanol or ethanol) to the extraction system. Such application for the extraction of lipids in the food industry is widespread, particularly with plant-based oils. However, the potential problems with the extraction of total lipids by SF has also yielded specific applications in the selective extraction or concentration of lipid components. Examples exist of the separation of FA from triacylglycerols (TAG) and squalene from sterols. 

Alcoholic beverages are heavily taxed in many countries, but besides being used to make drinks, ethanol has many useful industrial applications. It is used to make other organic chemicals and is an extremely useful industrial solvent. In order to avoid heavy taxation of the ethanol used for industrial purposes it is rendered unfit to drink (denatured). Small amounts of methanol are added to ethanol to produce industrial methylated spirit . A purple dye is often added to methylated spirit sold for domestic use. The dye serves as a warning that the mixture is undrinkable. 

Until about 1930, Boyle s methanol-making method remained in use. Today, it is made from synthesis gas. When steam reacts with coal, oil, or natural gas, it forms a mix of hydrogen and carbon monoxide. This mixture is known as syngas, and it can be reacted with a zinc-oxide/chromium-oxide catalyst to make methanol. Methanol is used as a gasohne additive (it makes the gas b um better), as an industrial solvent, and, of course, as an ingredient in windshield washer fluid. 

Butanediol, otherwise known as 2,3-butylene glycol (2,3-BD), is a valuable chemical feedstock because of its application as a solvent, liquid fuel and as a precursor of many synthetic polymers and resins. With a heating value of 27,200 J/g, 2,3-BD conq>ares favorably with ethanol (29,100 J/g) and methanol (22,100 J/g) for use as a liquid fuel and fUel additive (213). Dehydration of 2,3-BD yieldsthe industrial solvent methyl ethyl ketone which is much more suited as a fuel because of its much lower boiling point. Further dehydration yields... 

Economic, political and social pressures have influenced the manufacture of ethanol since the fermentation process was introduced many years ago (see Chapter 1). In the nineteenth century its status as an industrial solvent was assured when industrial methylated spirit, which is ethanol denatured with methanol to make it unfit for human consumption, was freed from excise duty. In the twentieth century, the social and political pressures which provide economic support for agriculture have allowed fermentation to compete effectively with petrochemistry as a manufacturing process. The technical achievements in chemistry, biology and engineering have only facilitated the switch between carbohydrate and oil as feedstock for the process. 

IV. INDUSTRIAL SOLVENT USES A. Methanol and Ethanol Uses... 

If, in place of water, the acid with the non-nucleophilic gegenion is added to a methyl alcohol solution of oxirane (ethylene oxide, oxacyclopropane), methyl cel-losolve [CH3OCH2CH2OH] is formed and addition of a second equivalent of ethylene oxide (oxirane, oxacyclopropane) yields CH3OCH2CH2OCH2CH2OH, methyl carbitol. Families of carbitols and cellosolves, resulting from the use of alcohols other than methanol, are common, high-boiling industrial solvents. 

PVA is produced on an industrial scale by hydrolysis (methanolysis) of PVAc, often in a one-pot reactor. Different grades of PVA are obtained depending upon the degree of hydrolysis (HD). Polymerization reactions can be carried out in batch or in continuous processes, the latter being used mostly for large-scale production. In the continuous industrial process, the free-radical polymerization of vir l acetate is followed by alkaline alcoholysis of PVAc. The molecular weight of PVAc is usually controlled by estabhshing the appropriate residence time in the polymerization reactor, vir l acetate feed rate, solvent (methanol) amount, radical initiator concentration, and polymerization temperature. 

In 1855, the ethanol manufactured in this process of fermentation and distillation was exempted from excise duty, provided it was first denatured with methanol. Only then was the resulting product (industrial methylated spirit) able to develop as an industrial solvent. Nor was it the last occasion on which a biological process needed the assistance of chemical technology (continuous distillation) and government intervention (exemption from duty) in order to become established. 

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