What are the fine chemical routes downstream of ethanol?

I see that the current progress of transformation of China’s chemical enterprises is more than expected, the most urgent of which are mostly focused on the by-products of chemical production, the expansion of the industrial chain of high-energy and high-pollution products, and the technological upgrading of bulk chemicals with serious homogenization. Ethanol in the past has always been used as alcohol, industrial fuels and other aspects of the production as a chemical raw material accounted for a relatively small. Under the slowdown of the overall daily consumption growth rate, as well as the influence of the new energy industry, the consumption growth rate of alcohol and industrial fuels has shown a slowing trend, with limited growth in the consumption scale, and many ethanol companies have been looking for new application directions. In addition, the continued development of the coal chemical industry has brought more supply of coal-based ethanol, which has also increased the pressure on the fine chemical transformation of the ethanol industry. What are the fine chemical downstreams that can be developed downstream of ethanol? Which routes are worthy of further research and exploration by ethanol enterprises?

First, what are the chemical reactions that can occur in ethanol?

The functional group of ethanol is hydroxyl group, so the chemical properties are mainly affected by the hydroxyl group and the neighboring groups affected by him, and the main form of reaction is the breaking of О-H bond and C-О bond. Ethanol is weakly acidic and, due to the polarized oxygen-hydrogen bonds, ionizes to alkoxy-negative ions and protons. Ethanol can also react with metal derivatives to form ethanolides such as sodium and potassium. In addition, ethanol can react with organic and inorganic acids to produce esters when dehydrated, commonly used strong acids, metal salts, ion exchange resins, etc. as catalysts. The properties of ethanol are also suitable for halogenation, dehydration, alcoholysis, oxidation, haloimitation, ammonification, etherification, esterification, alkylation and other reactions. For example, ethanol can be substituted with hydrohalic acid to produce halogenated hydrocarbons and water. Dehydration of ethanol is divided into intermolecular dehydration and intramolecular dehydration in two ways, intermolecular dehydration to generate ethers, intramolecular dehydration to generate olefins, such as ethylene. Ethanol and carboxylic acid derivatives such as acetyl halide, anhydrides, esters and other alcoholysis reaction to generate the corresponding ester, as well as ethanol and vinyl ketone, ethylene oxide, isocyanate and other reactive substances to react, respectively, to generate acetic acid esters, alkoxyl alcohols and ethyl carbamate, and so on. It can be said that ethanol can participate in a large number of chemical reactions, and there are many downstream product directions that can be expanded. However, due to the downstream refinement routes are characterized by high technical threshold and small product scale, relatively few ethanol fine chemical routes have been industrialized in China.

Second, what are the downstream fine chemical routes of ethanol?

According to my survey, ethanol is currently widely used in the direction of the main liquor and fuel, accounting for about 41% of the total consumption of ethanol and above; chemical production and pharmaceutical sterilization industry, accounting for about 39% of the total consumption of ethanol and above; about 18% made into anhydrous ethanol, downstream is applied in medicine, paint, sanitary products, cosmetics, oil and grease, and so on. In the field of fine chemicals, according to the ethanol downstream production process, can be divided into dehydration, amination, oxidation, esterification and other production methods, each production method represents at least one type of downstream products. Dehydration of ethanol can produce ethylene, high-carbon olefins, 2-pentanone, butanone, etc., which are not industrially produced in these application areas. Among them, the high-carbon olefins, including C3+ olefins, as well as the simultaneous by-production of C8-C16 olefins, the production technology began to be researched at a relatively early stage, which is mainly restricted to the downstream application areas with certain limitations. And ethanol dehydration preparation of 2-pentanone, auxiliary material for acetone, downstream mainly as solvents, spices and organic synthesis intermediates, etc., product consumption market is limited. In addition, ethanol dehydration coupling can be prepared butanone, downstream can be used as plasticizers, flavors and fragrances, organic solvents and dyes, etc., the application field is wider, but the method of industrialization there is a cost disadvantage. For ethanol amination production method, can prepare ethylamine, acetonitrile, N-ethyl aniline, N.N-dihydroxyethyl aniline and other products. For example, ethanol and liquid ammonia amination to prepare monoethylamine, diethylamine and triethylamine, all of which have been industrially produced in China, but the scale of production is not large. Monoethylamine can be used as the basic raw material for the preparation of dyes, rubber accelerators, surfactants, etc. It can also be used as the basic raw material for the manufacture of the pesticide simazine and atrazine; diethylamine is the basic raw material for the manufacture of pharmaceuticals, pesticides, dyestuffs, rubber vulcanization accelerators, textile auxiliaries, and metal anticorrosive agents, etc.; triethylamine is the basic raw material for the preparation of glyphosate and vinylidene carbonate, etc., which has many downstream fine chemical routes. By using ethanol ammonia dehydrogenation method, acetonitrile can be prepared, which is the basic raw material for chemical experiment, petroleum extraction agent, and as raw material for the production of etomidine, thiamine, α-naphthalene acetic acid, acetophenone and so on. For the production process of ethanol oxidation, acetaldehyde, acetic acid, acetone and other products can be prepared, of which acetaldehyde is the basic raw material product for the preparation of pyridine, 3-methylpyridine, acetic acid, ethanol, ethyl acetate and other basic raw materials. Acetic acid is the basic raw material for the production of acetic anhydride, acetic acid ester and cellulose acetate, downstream can be expanded in many directions; and acetone is the basic bulk raw materials, mainly as a solvent and other products, there is no ethanol oxidation method of acetone production. For the production process of ethanol esterification, can be prepared diethyl phthalate (DEP), diethyl adipate, ethyl acrylate, ethyl acetate, vinyl acetate and other products, some of the products have been industrially produced in China, but the production volume is relatively small. Such as DEP products, downstream can be used as plasticizers, solvents, lubricants, fragrance agents, non-ferrous or rare metal mine flotation foaming agent, etc.; and diethyl adipate products, is cellulose acetate, cellulose acetate butyrate and nitrocellulose plasticizer, is in some areas of the irreplaceable; Ethyl Acetate can be used in ink, paint, adhesives and pharmaceutical intermediates and other fields. In addition, ethanol can also be carbonylation reaction, the generation of propionic acid, including currently recognized as an effective preservative, in the field of grain, feed preservation has a very important application. Ethanol can be alkylation reaction, the preparation of ethylbenzene, diethylbenzene and other products under the name of styrene, pharmaceutical intermediates and solvents, but also dehydrogenated to prepare divinylbenzene, is a crosslinking agent of styrene, as well as the additives of ion exchange resins and so on. Ethanol and methanol one-step catalytic method for the preparation of isobutyraldehyde, downstream can be used as the synthesis of isobutene, MMA, MAA, methyl isopropyl ketone, neopentyl glycol and many other high-value-added fine chemicals, at present, the method is not yet in industrial production, but the industry is concerned about the higher. In addition, isobutylene and ethanol etherification can be prepared ethyl tertiary butyl ether (ETBE), used as a gasoline additive.

Third, which fine chemical routes downstream of ethanol are worth further study? As far as I know, although there are many fine chemical routes downstream of ethanol, not many of them have been industrialized, and most of them are still in the stage of theoretical research and small test. With the structural transformation of the chemical industry, in the production of products, ethanol as a chemical raw material for the chemical production advantage is expected to highlight, drive the scale of the landing. According to a rough assessment of industry experience, the current fine chemical routes worthy of further study are: ethanol carbonylation for the preparation of propionic acid, ethanol dehydration for the preparation of high-carbon alcohols and ethylene, ethanol oxidation for the preparation of acetaldehyde, ethanol esterification for the preparation of diethyl phthalate, ethanol amination for the preparation of ethylamine and special amines and other fields. Although the consumer market size of these several directions is on the small side, but the rate of product refinement is higher, downstream can be used as an organic chemical production of optional direction is more, is worth further research direction. Finally, I would like to say that ethanol has been developed in China for many years, has been used as fuel, medicine and oil applications, and did not give full play to its chemical production value, which is closely related to the previous chemical industry structure. This is closely related to the previous chemical industry structure. With the transformation of chemical industry structure and the innovation of chemical production technology, the application of ethanol as fine chemical production may increase more and more, and the utilization value is expected to be enhanced in the future.