With the increasing pressure and awareness of environmental protection in developed countries, in the 1980 and 1990s, it led to the eastward shift of global production of organic intermediates and trade center. Thus forms organic intermediates production area in China and India. The production and development of organic intermediates in China achieved great progress. There is a wide range of organic intermediates which are closely related to the pesticide industry.

Thionyl chloride is one of the few shortage of chlorine pesticide intermediates in recent years, China's major backward chlorosulfonic acid and co-generation process, chlorosulfonic acid method byproduct sulfur dioxide lead citrate and hydrogen chloride, the corrosion of the equipment and the environment pollution is very serious, low yield, product quality can not be guaranteed, only two products of the production of industrial thionyl chloride;-generation of chlorine and sulfur dioxide as raw materials, production of thionyl chloride byproduct of phosphorus oxychloride, high yield of the Act, but the binary separation, thionyl chloride, obviously there will be phosphorus composition affect product quality and production capacity to less contaminated, but the byproduct of phosphorus oxychloride, subject to market constraints, only Suitable for small-scale production. Abroad commonly used sulfur dioxide gas-phase process route, i.e., sulfur, sulfur dioxide, chlorine and other cheap materials, the product of high temperature activated carbon catalysis have finished, after distillation, the process method of the finished product colorless and transparent, good quality, while a small amount of vice The product can also be recycled, the basic three wastes, and can scale production, at present there are two companies from abroad sulfur dioxide gas technology to produce an annual production capacity of more than 10,000 tons / year. However, gas production in China will take further digestion, the product contains sulfur dichloride, and orange-red color was.

O-cresol is an important pesticide intermediates, Chinese demand is mainly dependent on imports. Of o-cresol preparation method is a natural separation from the fractionation of coal tar, due to limited resources musk R-1, coupled with the complex process, many separation devices such as inadequate, and therefore developed a number of chemical synthesis. At present, China mainly uses natural separation and serious pollution of otoluidine diazotization hydrolysis. Major foreign advanced phenol alkylation, the presence of a catalyst, the gasification of phenol and methanol into the fixed bed catalytic reactor reaction, the main product was o-cresol, byproduct 2,6 - dimethyl phenols. The hospital with the production of this technology to build a kiloton device. The key technology is the selection and use of catalysts in the phenol alkylation process, the way out of another by-product 2, 6 - xylenol, 2, 6 - xylenol is mainly used for the synthesis of polyphenylene ether.

Catechol is an important pesticide intermediate. It mainly relied on imports of Chinese demand in 2000. Only a few manufacturers adopt dichlorobenzene and chloroprene with backward, serious environmental pollution and poor quality. There are three manufacturers abroad using the phenol hydroxylation method. The three companies are not transfer of technology. In order to break the monopoly of foreign companies, China has taken a breakthrough with the annual production capacity has reached 1400 tons. It can be said that the industrial technology of phenol hydroxyl is matured. China already has the ability to build million thousands-ton production equipments.  Source:http://www.mhcfm.com