The Prospect of Phenylacetic Acid in the "Tenth Five Years"

Phenylacetic acid is an important fine chemical intermediate, widely used in medicine, pesticides, spices, dyes and other fields.

There are two main routes for the industrial synthesis of phenylacetic acid at home and abroad. One is the hydrolysis of phenylacetonitrile. This method is a traditional production method. Due to the use of highly toxic sodium cyanide as raw material, serious pollution, large amount of “three wastes”, and poor product quality affect the application of follow-up products, the yield is low, and it faces elimination. However, it is currently mainly used in China. The law produces. The second is benzyl chloride carbonylation. This is a newly developed phenylacetic acid production technology in the past decade or more, with mild reaction conditions, avoiding the use of sodium cyanide, high yield, and easy availability of raw materials. Moreover, the reaction does not require high purity of CO, and industrial wastes rich in CO, such as Yellow phosphorus tail gas, closed calcium carbide furnace gas, ammonia scrubbing regeneration gas, converter steelmaking tail gas, etc. can be used for the preparation of phenylacetic acid. In the 1980s, research on the chlorobenzylation of phenylacetic acid in foreign countries was very active. At present, Germany, Japan, Italy and other countries have adopted this method for industrial production. In recent years, a number of domestic research institutes have conducted research on this process and achieved substantial breakthroughs and progress. Four sets of benzyl chloride carbonylation process industrial installations have been successively built in China. The key to this method lies in the selection and recovery of catalysts. At present, the main catalyst used in the country is cobalt carbonyl.

There are currently nearly 30 phenylacetic acid manufacturers in China with a total annual production capacity of about 20,000 tons. Most of the companies are small in scale. The largest one is an annual output of 2,000 tons, and the others are mostly with an annual output of several hundred tons. The technology is backward, and over 80% of the enterprises use it. The benzene acetonitrile hydrolysis method has high production cost and serious “three wastes” pollution; the product quality is poor, and the use of toxic cyanide products tends to affect the use of downstream products. As a result, many companies are in production or semi-discontinued state. In 2000, the output was about 12,000 tons. Domestic Shijiazhuang Chemical Plant, Jining Electrochemical Plant, Deyuan Fine Chemical Plant and Suihua Chemical Fertilizer Plant are produced by benzyl chloride carbonylation process, with a total annual production capacity of approximately 3,000 tons.

Phenylacetic acid is mainly used as an intermediate for medicines, pesticides and spices. In 2000, the consumption of phenylacetic acid in China was 11,200 tons. The proportion of consumption was: medicine accounted for 88%, pesticides accounted for 3%, spices accounted for 7%, exports and other 2%. In medicine, phenylacetic acid is mainly used to prepare penicillin G salt; secondly it is used to prepare sedative and anti-epileptic drugs such as phenobarbital and primidone; antidepressant amitriptyline; Barzol, clorox, anti-cholinergic drugs atropine, Xie Ling, anti-rheumatic drugs and appetite suppressants. Among them, for the synthesis of penicillin, accounting for 85% of the total consumption of phenylacetic acid, other drugs accounted for 3%. China is the world's major producer and exporter of penicillin G. Due to the difficulty in the production process of penicillin and the serious pollution of “three wastes”, leading Western producers have stopped production and brought good development opportunities to China. The production of penicillin in China increased from 2,000 tons in 1990 to 12,000 tons in 2000, accounting for about 25% of the world's total production. In recent years, due to the rapid increase in penicillin in India and the rampant smuggling activities, the export price of penicillin in China has continued to decline, which has seriously affected the development of the domestic phenylacetic acid market. Since last year, the world penicillin market has gradually improved and prices have continued to rise. As soon as China joins the WTO, the situation of penicillin exports will become better and better in the future. In addition, penicillin side chain compounds have been actively studied and applied in recent years. The addition of β-lactamase inhibitors to penicillin improves penicillin efficacy, reduces the effects of drug resistance, and promotes the reform of the employee medical system throughout the country. Indeed, penicillin has become the preferred antibiotic for people at low prices. It is expected that penicillin will not shake the leading position of domestic antibiotics for a long period of time, and domestic consumption will increase by a certain extent in the future. The consumption of phenylacetic acid by other drugs is small, and there will be no significant increase in demand in the next few years. It is estimated that in 2005 China's pharmaceutical industry will consume about 40,000 tons of phenylacetic acid.

In terms of pesticides, phenylacetic acid can be used for the preparation of insecticides such as rice phytochemicals, trichlorfon, triterpenoids, bactericide benzoicin, herbicide trichlorophenylacetic acid, rodenticide DaLung, rattrace, triterpene, chlormone Wait. The pesticide industry consumed about 340 tons of phenylacetic acid in 2000. Because the pesticide industry consumes less and most of the pesticides produced are traditional pesticides, there will be no significant growth in the future. It is estimated that in 2005 China's pesticide industry will consume 500 tons of phenylacetic acid.

In respect of spices, phenylacetic acid esters are edible flavors permitted by our country. As a substitute for earthworms or civetes, they can be formulated with aromas such as acacia, osmanthus, and roses, as well as aromatherapy. It is mainly used for the production of foods, detergents, cleaners, cosmetics, tobacco, beverages, etc. Furthermore, phenylacetic acid ester also has aromatherapy effect of controlling appetite and has a very good clinical effect on adjuvant treatment of obesity. According to relevant information, spices consumption in Europe and the United States and other developed regions accounted for more than 30% of the demand for phenylacetic acid, and phenylacetic esters in the international market occupied a very important position in esters and fragrances, and demand increased year by year. Due to insufficient attention to the development of downstream products in China, only a few companies currently produce phenylacetate series products. It is expected that the fragrance industry will be a fast-growing area of ​​phenylacetic acid consumption in China. In 2005, it will require about 2,000 tons of phenylacetic acid.

In addition, phenylacetic acid can also be used in high performance engineering plastics, fluorescent brighteners, dyes, liquid crystal materials and other fields. With the increase of environmental protection pressure and the rapid development of China's fine chemicals, the price of phenylacetic acid has dropped. Certain products based on phenylacetonitrile may shift to the use of phenylacetic acid. Therefore, the demand for phenylacetic acid in the field of fine organic synthesis may increase at a faster rate. increase. In the past, phenylacetic acid has been a relatively scarce intermediate in our country, and it needs to import thousands of tons from abroad every year to meet domestic demand. Stimulated by the huge market demand, in the early 1990s, there was a boom in the construction of phenylacetic acid in China. The output increased year by year, and the amount of imports decreased. In 2000, there was almost no import, and about 150 tons were exported. Due to environmental pressures and other factors, developed countries in the world have restricted the development of chlorine-based organic products, and their enthusiasm for new construction or production expansion has been low, and they have even decreased year by year. Therefore, the prospects for the export of phenylacetic acid in China are promising. It is estimated that the demand and export of phenylacetic acid in other fields in 2005 will be about 1,500 tons.

Phenylacetic acid is a fine chemical intermediate in our country that has considerable production capacity, but product quality and synthesis technology can not meet future development needs. As China's accession to the WTO is approaching, the export prospect of phenylacetic acid and its downstream products is getting better and better. To this end, the following suggestions are made for the industrial development of phenylacetic acid in China: First, with the maturation of the chloroacetoxylation process for the synthesis of phenylacetic acid, domestic manufacturers should join hands with the scientific research departments to improve and improve the chlorobenzyl carbonylation technology. The benzene acetonitrile hydrolysis method was modified to allow the qualified companies to use the benzyl chloride carbonylation method to build large-scale production equipment as soon as possible. Second, phenylacetic acid production of raw materials, benzyl chloride at low domestic prices, adequate supply, can provide raw material for phenylacetic acid production guarantee, so the domestic should vigorously develop the downstream products of phenylacetic acid, especially the development and application of phenylacetate series products. At the same time, it is necessary to accelerate the pace of phenylacetic acid in place of phenylacetonitrile and promote the production and consumption of phenylacetic acid Third, while strengthening production, seize the opportunity to occupy the international market with products of high quality and low price, because efforts to expand product exports is one of the important drivers for the development of phenylacetic acid in China.