Pyridines and Pyridine-based Pesticides Have Bright Prospects     
By Han Yongqi, Han Chenxi   

Pyridine is a widely used category of heterocyclic compounds and an important raw material for fine chemicals. Its derivatives include 2-methyl pyridine, 3-methyl pyridine, 4-methyl pyridine, chloropyridines. They are mostly used in pesticides, pharmaceuticals, dyes, daily chemicals, spices, feed additives, rubber additives, etc. In particular, the amount used as a pesticide intermediate is increased significantly. In recent years, application of those pesticides containing some member of the pyridine group saw rapid growth not only in highly effective insecticides and commercialized herbicides, but also in highly effective bactericides that had already been developed by some companies around the world. Gradually these applications gave rise to a unique pesticide series with a huge number of classifications. China is the biggest importer and exporter of pesticide active ingredients in the world, with 2 600 pesticide companies, 400 of which are able to produce pesticide active ingredients. Currently, compounds with structure of pyridine rings have become the key innovative direction for the groundbreaking producers of pesticide active ingredients. China already has the ability to produce a diversified series of pyridine based pesticides.
   It was reported that the global output capacity for pyridines is about 140 thousand t/a, and synthesis accounts for 95% of the total output. The major producers of pyridine compounds including the US, the EU and China account for more than 80% of the global total output. With global agriculture developing and downstream industries blossoming, the global pyridines market is expanding constantly.
    Before 2000, China had no units to synthesize pyridines. The traditional technique of separating coal tar was predominant, and even that means of production was capable of less than 200 t/a. Meanwhile, because impurity of the products was a problem, the development and production of downstream products was seriously restricted. The 11 000 t/a pyridine unit of Nantong Reilly Chemical Company Limited was started up smoothly (CCR2001 NO12) in 2001, which was also the first unit using synthesis technology to produce pyridines in China. This unit has been expanded to 22 000 t/a in 2005 (CCR 2005 No.15). But generally, all of its products have been supplied to Syngenta Corporation, not to Chinese manufacturers.
    Now, two more large scale units for producing pyridines by synthesis method and their downstream products have been set up by the Red Sun Group Corporation in Nanjing site of Jiangsu province and Dangtu site of Anhui province with a capacity of 11 thousand t/a each, making five categories of products including pyridines and 3-methyl pyridine. In addition, Shanhaiguan Wantong Adjuvant Factory of Hebei Binyang Group makes 2-vinyl pyridine, 2-chloride-4-cyanpyridine, 2-chloride-4-aminopyridines; Tianjin Jingfu Fine Chemicals Factory, chloropyridine series; Shanghai Songjiang Tiannan Chemical Factory, amino-pyridine series; Hebei Yanuo Chemical Industry Co., Ltd., pyridine series (including hydroxypyridines, bromopyridines, chloropyridines, and aminopyridines); Yingkou Zhonghai Fine Chemicals Factory, N-ethyl-pyridone series;  Changzhoushi Jiangchun Chemical Plant, alkyl pyridine; Zhejiang Huayi Pharmaceutical Co., Ltd., pyridines used in making drugs; Wujin Tengfan Fine Chemical Factory, cynopyridies and nitropyridines; and Henan Taiqian County Essence Perfume Plant, 3-methyl pyridine, all of which are sold to foreign countries.
   In recent years, China's pesticides made using the pyridine group have developed rapidly, becoming the 4th wave of innovation in pesticides. In addition to high efficiency, low toxicity, long persistence, it is also environmentally compatible with people and animals, conforming to development requirements and trends. Because pesticides with the pyridines cover three categories: insecticides, herbicides, and fungicides, chemical compounds with the pyridine group are becoming the main innovative direction for pesticides. For the next three years, the consumption of the world's main categories of pyridine pesticides is expected to grow more than 15% annualized, faster than the overall growth of the pesticides industry, while the consumption growth of "pyridine bases" (a generic name of pyridines and their derivates) will reach about 20%. However, throughout the world, prices for the downstream chemical compounds of the pyridines are relatively high because Switzerland's Lonza AG and Reilly Industries, Inc. of the US have IP control of the technology for producing pyridines. For example, China has only two sets of units for producing 3-methyl pyridine: one is the unit of the 110 thousand t/a series built by Reilly Industries, Inc. and Nantong Acetic Acid Plant's JV, making up to 3 000t/a 3-methyl pyridine; the other is the unit for 110 thousand t/a of pyridines and its downstream products of the Red Sun Group Corporation, making 3-methyl pyridine with an output capacity of 2 000t/a. But Nantong Reilly's products are mainly exported; the Red Sun Group's 3-methyl pyridine unit mainly supplies for its own downstream pesticides and intermediates facilities. Therefore, other downstream users of 3-methyl pyridine in China rely on imports. Currently, China's apparent consumption of 3-methyl pyridine per year is between 4 000 tons and 4 500 tons, of which annual demand in making nicotinic acid and nicotinamide is around 2 000 - 2 500 tons together, and demand in the pesticide sector is about 1 500 tons. With the rapid development of China's pyridine based pesticides, the demand for the 3-methyl pyridine in the future markets looks promising.
   At present, chemical compounds with pyridine structure have become the main innovative direction of new pesticides. With the fast development of China's pesticide industry, demand for pyridines for use in making pesticides will be strengthened further, while fine chemical compounds that include pyridines are currently fairly urgently needed in China's market. Because Chinese production processes for making pyridines are comparatively backward (excluding the Red Sun Group Corporation), the supply of pyridines is in short. The development and application of the pyridine downstream products are seriously restricted. If China's pyridines and pyridine based pesticide enterprises want to make great progress or compete globally, they need do more innovations in research & development, technology and management.