Production status and development suggestions of p

Production status and development suggestions of p-dichlorobenzene in China

p-dichlorobenzene is a widely used fine chemical product, which is widely used in medicine, pesticides, engineering plastics, dyes, catalysts and so on

the research and development of dichlorobenzene in China started relatively late. At the beginning, it was mainly recovered from the by-products produced by chlorinated benzene. With low output and poor quality, it was not suitable to be used as moth and mildew inhibitor. With the development of dyestuff, medicine and other industries in China, as well as the development and utilization of derivatives of p-dichlorobenzene, its demand is increasing, so the research and development work on the preparation of p-dichlorobenzene by directional chlorination of benzene under the action of specific catalysts has begun. At present, the total production capacity of p-dichlorobenzene in China is about 26000 tons/year, and the output is about 6000 tons/year. The manufacturers mainly include Tianjin chemical plant (production capacity of 3000 tons/year), Shandong pesticide plant (production capacity of 2000 tons/year), Jinxi Chemical Plant (production capacity of 6000 tons/year), Nantong pesticide plant (production capacity of 3000 tons/year) Handan Fuyang chemical plant (with a production capacity of 3000 tons/year), Tangshan chlor alkali plant (with a production capacity of 6000 tons/year), Nanjing chemical plant (with a production capacity of 300 tons/year), Zhangdian pesticide plant (with a production capacity of 2000 tons/year) and Henan Lankao fine chemical plant (with a production capacity of 1000 tons/year), etc

p-dichlorobenzene produced in China is mainly used to replace refined naphthalene for moth and mildew prevention. Therefore, when there are many kinds of samples for experiments, the current consumption is about 10000 tons/year. It is expected that the demand will reach about 15000 tons by 2005. In addition, p-dichlorobenzene is mainly used as the raw material of polyphenylene sulfide, a special engineering plastic with excellent production performance. At present, the production capacity of polyphenylene sulfide in China is about 500 tons/year, and the output is only about 200 tons/year, which is far from meeting the actual domestic production demand. The development prospect is very optimistic. It is expected that by 2005, the demand of polyphenylene sulfide in China will reach about 3000 tons/year, and about 4000 tons/year of p-dichlorobenzene will be consumed at that time. Together with the demand in the pesticide and dye industry and other downstream products, it is estimated that the total demand for p-dichlorobenzene in China will exceed 20000 tons/year by 2005. At present, although the total production capacity of dichlorobenzene plants in China has reached 26000 tons/year, due to technical and other reasons, a considerable number of plants have been stopped or the operating rate is very low, and the actual total output is only about 6000 tons/year, which greatly limits the development of dichlorobenzene industry in China. In order to promote the rapid development of China's p-dichlorobenzene industry and meet the needs of domestic actual production, it is suggested that:

(1) speed up the pace of scientific research and improve the key technology level

at present, most domestic p-dichlorobenzene manufacturers adopt intermittent chlorination process and backward separation technology, which is difficult to participate in market competition. Therefore, it is necessary to improve the production level of China's p-dichlorobenzene as soon as possible, We should cooperate with relevant manufacturers and scientific research departments to continue to carry out the research and application of synthetic directional catalysts, improve the level of directional chlorination prediction in the next few years, screen out the directional catalysts with high ratio of para and ortho dichlorobenzene through scientific research, and apply them to production. Develop continuous chlorination devices suitable for large-scale production, and at the same time, introduce foreign advanced continuous chlorination technology and key equipment, so as to change the backward situation of p-dichlorobenzene production process in China as soon as possible. Research and promote the establishment of China Green Manufacturing Alliance, research new para dichlorobenzene separation technology, and focus on automatic, low-energy static crystallization and dynamic crystallization research. Carry out the development of p-dichlorobenzene granulation technology, solve the problem of packaging caking, and improve the competitiveness in the international market

(2) accelerate the development of downstream products

at present, the production capacity of p-dichlorobenzene in China has reached 26000/year, but the output is only about 6000 tons/year, and the equipment operation is seriously insufficient. The main reason is the insufficient development of domestic downstream products and insufficient consumption. Therefore, the focus of domestic development in the future is to vigorously develop downstream products. The development of p-dichlorobenzene and the development of downstream products should be organically combined, and the cross industry cooperation and unified planning should be carried out to make the downstream products develop synchronously with the p-dichlorobenzene industry, so that mold proof, moth proof, deodorant can be used in multiple varieties, models, serialization, low cost and different occasions, expand domestic demand, and start the domestic market, so as to promote the development of p-dichlorobenzene production and make it a bulk fine chemical product in China. P-dichlorobenzene is mainly used in the production of insecticidal, mildew proof, deodorizer, polyphenylene sulfide resin, pesticides and dyes. In the aspect of insecticidal, mildew proof and deodorizer, p-dichlorobenzene replaces refined naphthalene to produce insecticidal and mildew proof agent, which not only has excellent performance, but also has a high safety factor. However, at present, the domestic use of p-dichlorobenzene moth proof and mildew proof agent has not aroused the interest of urban and rural residents, so we must do a good job in advertising and publicity, and tap the potential that has been used in naphthalene sanitary balls, And actively open up foreign markets. Polyphenylene sulfide (PPS) is a special engineering plastic with excellent performance produced from p-dichlorobenzene. The annual demand abroad has maintained a double-digit growth rate in the past decade. At present, the output of polyphenylene sulfide in China is far from meeting the actual production demand, and it mainly depends on imports. It is suggested that China should strengthen the development of polyphenylene sulfide production technology and build several thousand ton polyphenylene sulfide production units as soon as possible, so as to meet domestic demand on the one hand and promote the consumption of p-dichlorobenzene in this field on the other hand

(3) expand the production scale and improve the production technology level

according to the production plant scale of p-dichlorobenzene in foreign countries and the production situation in China, the ideal production scale should be in tons/with the addition of merican Millard? Polypropylene with nxtm8000 transparent agent can become transparent and transparent for years, but at present, only Jinxi Chemical plant has reached 6000 tons/year. Therefore, relevant manufacturers should improve the existing p-dichlorobenzene production plant and production process to improve the operating rate and product quality. Qualified manufacturers can also expand the production scale according to the actual situation, so as to reduce production costs and improve economic benefits

compared with foreign countries, the existing domestic technology for the production of chlorobenzene is less flexible, that is, a set of equipment can not produce monochlorobenzene and dichlorobenzene at the same time, while the production capacity of monochlorobenzene has tended to be saturated, and the existing output of dichlorobenzene can not meet the market demand. It is necessary to carry out appropriate technical transformation on the existing equipment of chlorobenzene, and implement the joint production of monochlorobenzene and dichlorobenzene. Control the production proportion according to the market sales situation, and improve the competitiveness of enterprise products in domestic and foreign markets