Trimethylacetic acid is an important chemical raw material and chemical reagent. As an organic intermediate, it is widely used in the synthesis of fine chemicals.
The preparation method of trimethylacetic acid is different from common fatty acids. Currently, there are more than 10 kinds of synthetic processes. The industrialization or industrialization prospects mainly include the following: methyl imidi tert-butyl ketone haloform reaction; tert-butyl magnesium chloride react with carbon dioxide; Alcohol or t-butanol reaction with formic acid; Reppe reaction; Koch reaction. Among them, the first three methods have complex technological processes, high production costs and low yields, and are not suitable for large-scale industrial production. They are only suitable for small-scale or laboratory production. The Reppe reaction is a conventional carboxylic acid preparation method. An olefin, carbon monoxide and water are reacted to obtain a normal or isomer mixture of carboxylic acids. However, the trimethyl acetic acid obtained by this method has a low proportion and only accounts for 5% of the total production. 10%, but the production of trimethylacetic acid in the production of other carboxylic acid. Koch reaction takes isobutylene, carbon monoxide and water as raw materials to prepare trimethylacetic acid, the yield can reach 70% to 80%, and the purity of the product can reach 98%, thus becoming the main method for the industrialization of trimethylacetic acid. The key to this process technology lies in the development of catalysts. Commonly used catalysts include sulfuric acid, phosphoric acid, hydrofluoric acid, BF3 catalysts, and solid acid catalysts. Among them, nowadays, foreign industrial equipment mainly uses phosphoric acid and BF3 catalysts. Because the catalysis process of the solid acid catalyst is easy to control, and the corrosivity is small, the separation of the product and the catalyst is easy, which has become a hot spot in recent years and has considerable potential for development.
The pivaloyl peroxide initiator prepared by the reaction of trimethylacetic acid chloride with tert-butyl hydroperoxide is also called PV initiator. It is a high-efficiency initiator for low-density polyethylene. It is also vinyl chloride, acrylate, vinyl acetate, etc. The polymerization initiator is very stable compared to other initiators and can be used in aqueous solutions at various pH levels and at low temperatures. The polymer produced by using it as an initiator has good thermal stability, good electrical insulation properties, and is non-toxic. It has the advantages of relatively large molecular weight in structure and is widely used abroad. In Japan, new peroxide initiators synthesized from trimethylacetic acid have been used in recent years to oxidize tert-pivalyl peroxide, which can significantly shorten the polymerization reaction time, increase the production efficiency, and produce a uniform heat release during polymerization in PVC suspension production. The appearance of the product is good.
Trimethylacetic acid is used in the pharmaceutical industry to produce ampicillin, amoxycillin, cefazolin type antibiotics. Ampicillin is a new type of high-efficiency antibiotic, which is superior to penicillin in its performance. It has broad prospects for development in China. Currently, there are nearly ten companies in the country, with a total production capacity of about 300 tons per year. The raw material trimethylacetic acid is all dependent on imports. In addition, prednisone prepared by hydrogenation of trimethylacetic acid has good solubility, high curative effect and small side effects and can be used for treating rheumatoid arthritis. Benzoyl trimethyl acetic acid improves blood vessel stability and is used to treat active ingredients in psoriasis ointment. Trimethylacetic acid can also produce furazolidone, bis-pentaephrine and the like.
In the pesticide industry, linalone, which is synthesized from trimethylacetic acid and acetone, is a very tight pesticide intermediate in China. Chorionone can synthesize many new bactericides, plant growth regulators and insecticides. These products are characterized by high efficiency, low toxicity, internal absorption, broad spectrum, low dosage and long residual period.
In the perfumery industry, trimethylacetate is resistant to hydrolysis and has a certain aromatic odor. It can be used as a fragrance additive for soaps, shampoos, and hair gels. Different esters have different aromas, and the fragrance is pure, long-lasting and difficult to decompose.
In the coatings industry, polyacrylate coatings obtained using trimethylacetic acid as an initiator are more resistant to aging, have better gloss retention, and retain high gloss in harsh environments compared to coatings obtained using conventional initiators. . Powder coatings are favored because they do not use solvents. The glycidyl ester made of trimethylacetic acid as a treating agent for the epoxy resin powder coating enables the powder coating to have excellent color and gloss, and is durable and not easily decomposed.
China began to research and develop trimethylacetic acid in the 1970s, but there are no industrialized production devices yet, which limits the development and application of its downstream products. At present, China imports a large amount of PV initiators and trimethylacetate for pharmaceutical production. With the development of China's petrochemical industry, the demand for trimethylacetic acid has increased rapidly, and the prospects for domestic development and production of trimethylacetic acid are promising. Therefore, domestic qualified petrochemical companies may consider building a C5-C11 carboxylic acid production plant with an annual output of 5,000 to 10,000 tons, and arrange production of trimethylacetic acid, isophthalic acid and other carboxylic acids required for fine chemicals according to market demand. Among them, the Koch reaction can be used as the first choice process, and the development of solid acid catalysts that meet the requirements of environmental protection.