Clean Production Technologies to Replace Chemical Pollution Projects Lu Liyi, He Wenjun, Lu Wenkui (Shanghai Institute of Petroleum and Petrochemicals, Shanghai 201208, China) Production Technology. In clean coal. Propylene oxide. Dimethyl carbonate. Polyether. Cumene. Acrylonitrile. Propylene glycol ether and other projects have put forward corresponding suggestions.

At present, human society is facing the worst environmental crisis in history. Green chemistry is an inevitable choice for human survival and social sustainable development.

The CHP synthesis of propylene oxide can be regarded as an improvement of the traditional co-oxidation method (Halcon method). It not only avoids the problem of the joint product, but also reduces the production cost of propylene oxide, so that the new equipment using the Sumitomo process can get stable income after the production.

According to reports, Shell, which currently holds the leading position in the technology of ethylbenzene and co-oxidation, is also researching this new process. There are also several fund projects: Shanghai Science and Technology Development Fund Soft Science Project "Shanghai Chemical Industry Clean Production Technology Propulsion Research* (016921012)::2003 Urban Environment and Urban Ecology Volume 16 Issue 6 Considering cooperation with Sumitomo in 2003. These indicate that the CHP method has a very good prospect of industrialization.

Shanghai currently has an annual production capacity of 60,000 tons of propylene oxide units, and plans to expand to 100,000 tons using heavily polluted chlorohydrin. Shanghai Chemical Industry Park has invested in the construction of an ethylbenzene dehydrogenation styrene plant with an annual output of 500,000 tons. In this case, if it is to replace the chlorohydrin method and synthesize various methods, it is recommended that the CHP method be developed.

3 Green Products Green Preparation and Application of Dimethyl Carbonate Currently, there are Shanghai Wujing Chemical Plant, Jiangsu Wuxian Pesticide Plant, Chongqing Changfeng Chemical Plant, Liaoning Fuxin Organic Chemical Plant, and Asia Pacific Agricultural Chemicals (Group) Company Shanghai Dongfeng Chemical Plant phosgene method. The total production capacity of DMC production of 2 300t/a is about 1000t. The actual potential of DMC production is huge.

3.1 Synthesis of dimethyl carbonate The molecular structure of dimethyl carbonate is: (CH3)2CO. In the synthesis of DMC, there are currently two routes with industrial value, namely petrochemical route (also known as transesterification method) and coalification route. (Also called methanol oxidation carbonylation method).

Produced with phenol. DMC can be used instead of methyl chloride to make tetramethylolamine (TMAH). DMC is a promising gasoline oxygen and anti-riot additive that can improve the low-temperature solubility of ethanol gasoline and can be used as a co-solvent. Another important use of dimethyl carbonate is the synthesis of 3.3 recommendations (1) the use of domestic technology to use the petrochemical route to build dimethyl carbonate production facilities, replacing existing phosgene production of dimethyl carbonate technology; (2) introduction or Develop its own technology for the production of polycarbonate from dimethyl carbonate; (3) Use dimethyl carbonate instead of dimethyl sulfate as a methylating agent to stop or minimize the production of highly toxic dimethyl sulfate.

4 Bimetallic Catalytic Preparation Polyether polyether polyols (polyethers for short) are raw materials for polyurethane products. With the rapid development of polyurethane in China in these years, the demand for polyurethane has also risen sharply. Since 1996, the domestic production of polyether has been longer than 20%. Although this temporarily eases the demand for polyether in the domestic market, the amount of imported polyether also increases year by year, and is slightly higher than that of domestic polyether.

The petrochemical route involves the following reaction: It is clear that the petrochemical route for the synthesis of dimethyl carbonate is a very typical green chemistry route. At the same time, it is also a green route for the synthesis of ethylene glycol because the traditional route for the production of ethylene glycol is more by-products. Ethylene glycol. At present, the East China University of Technology 1000t/a DMC demonstration unit is in operation.

3.2 The cleansing of dimethyl carbonate The application of dimethyl carbonate can replace phosgene to produce polycarbonate, replacing the transesterification method that currently uses highly toxic raw materials.

Dimethyl carbonate can replace phosgene to produce isocyanate. The use of DMC to produce isocyanates solves the problems of traditional process materials and intermediates such as high toxicity, severe waste, and device corrosion. It is a promising process route 16. DMC can replace toxic dimethyl sulfate (DMS) as a methylating agent. , such as anisole (anisole) is currently used as alcohol DMS Shanghai current polyether production capacity of 80,000 t / a for Shanghai there are several suggestions: (1) for the original polyether plant to use clean and efficient double For the large-scale construction of metal-catalyzed process (2) in conjunction with isocyanate, it is recommended to build or expand a polyether production plant using a bimetallic catalytic process; (3) Since polyethers require ethylene oxide and propylene oxide as raw materials, Shanghai With the mass production of ethylene oxide, it is recommended to build or expand the production unit for propylene oxide.

5 Synthesis of cumene Propylene and benzene alkylation Synthesis of cumene is an important part of phenol acetone production. There are two main processes: a liquid phase bubbling reaction catalyzed by aluminum chloride and a fixed bed reaction process using a solid acid catalyst. The former include the aluminum chloride method of SD Company and the modified aluminum chloride method of Monsanto Company. The product yield is particularly high, but its disadvantage is that the highly polluting aluminum trichloride is used as a catalyst, and the environmental protection is increasingly strict in today's environment. In the case of promotion, the promotion is limited; the latter mainly includes the U0P method using a solid phosphoric acid as a catalyst and the method using a zeolite catalyst. However, the corrosiveness of solid phosphoric acid to the reactor is relatively larger than that of zeolite, and the quality of the product is still relatively serious. Zeolite catalytic fixed bed process has been successfully developed and rapidly promoted since 1994. The key is the use of non-corrosive, non-contaminating zeolite as a catalyst. Only a slight improvement of the reactor in the solid phosphoric acid process can be put into use. The original solid phosphoric acid process can be prepared by changing to the methylation reagent of the zeolite catalyst. Li-C can be used instead of the Li-S process. The device can increase the yield and the yield is close to 10%. Currently, Lu Liyi and other alternative chemical pollution projects are supported. Clean production technology companies with zeolite fixed-bed process property rights include: Enichem, Mobil/Badger, UOP, Dow/Kellogg and others. Domestically, the Sinopec Shanghai Research Institute of Petroleum and Petrochemicals owns the zeolitic method to prepare cumene. Currently, it is developing catalysts with higher performance (such as low benzene/propylene ratio, thus reducing energy consumption).

Gaoqiao Petrochemical Company will expand the existing approximately 140,000 t/a phenol/acetone plant to nearly 180,000 t/a. Shanghai Chemical Industry Park will build a new 200,000 t/a phenol/acetone plant. Current devices use zeolite and aluminum trichloride methods, respectively. It is therefore recommended that: (1) Older devices that currently use aluminum trichloride should be replaced by a clean zeolite process. (2) For later installations, a new generation of catalysts with higher performance (lower energy consumption and material consumption) is used.

6 Acrylonitrile production uses less ammonium sulfate technology and non-sulfur ammonium technology Acrylonitrile has a wide range of uses as an important organic chemical raw material. It is an important monomer for synthetic fibers, synthetic rubber and synthetic resins. Acrylonitrile production methods are: cyanohydrin, acetylene, propylene ammoxidation. The first two methods not only produce raw materials with high toxicity, but also have higher production costs than the latter. Propylene ammoxidation has the advantages of cheap and easy access to raw materials, low production cost, and simple production process, and is the main method for the production of acrylonitrile at home and abroad. The downstream demand for acrylonitrile in the domestic market is quite large and the demand potential is huge. At present, nearly one-third of the global acrylic fiber market is in China. Shanghai currently has 60,000 t/a of acrylonitrile units and is expanding 70,000 t/a in addition to building 260,000 t/a. Unreacted ammonia in the acrylonitrile production plant is absorbed by sulfuric acid to produce ammonium sulfate. However, this process brings three problems: (1) wastewater contains unpurified ammonium sulfate, and sulfur and nitrogen oxides are also generated in the exhaust gas, resulting in pollution; (2) the economic efficiency of recycled ammonium sulfate is low; (3) The loss of raw material ammonia due to the production of acrylonitrile, and the consumption of sulfuric acid in addition, wastes resources. Due to the above drawbacks, there are currently proposed less ammonium sulfate technologies and non-sulfur ammonium technologies. The core of this technology is to increase the catalyst's conversion rate to ammonia so that ammonia can be converted as much as possible and the remaining ammonia can be reduced as much as possible. Less ammonium sulfate technology and non-sulfur ammonium technology reduce pollution at the same time and belong to clean production processes.

At present, there are two units in Shanghai that produce acrylonitrile catalysts. It is recommended to develop high ammonia conversion catalysts to provide technical support for less ammonium sulfate technologies and non-sulfur ammonium technologies in the production of acrylonitrile, thereby reducing pollution and developing clean production processes.

7 Development of Propylene Glycol Ether Production Propylene glycol ether and glycol ether belong to the same glycol ether and are excellent industrial solvents. In the coatings, printing, dyes, cleaning agents and other aspects of the series of products are low toxicity, most of the animals and organs The organization has no adverse effect. Since the physical and chemical properties of propylene glycol ether series products and glycol ether series products are similar, glycol glycol ether series products can be directly or slightly adjusted.

Shanghai currently has a production facility of 3,000 t/a. From the point of view of cleaning products, propylene glycol ether is significantly better than ethylene glycol 9. However, the market price of glycol ether is lower than that of propylene glycol ether. Toxic B is still widely used in coating solvents. Glycol ethers. With the increasingly stringent production policies, the use of propylene glycol ethers is a development trend. It is recommended that Shanghai support the production of propylene glycol ethers.

In addition, there are also some clean technologies related to Shanghai, such as butadiene extraction agent, in the related solvents. At present, more toxic acetonitrile (ACN), dimethylformamide (DMF), dimethyl sulfoxide are used. (DMSO) and the like, while N*methylpyrrolidone (NMP) is relatively low in toxicity. Polyurethane foaming agents currently use Freon that is harmful to the atmosphere, and non-toxic and non-toxic polyurethane foaming agents such as cyclopentane and pentane have been successfully developed. The use of supercritical carbon dioxide instead of organic solvents as sprays for paints and coatings, instead of organic solvents as cleaning agents, reaction solvents, and alternative solvents such as Freon as foaming agents for styrene foams, have been applied in industry. Zhou Zhongping, Zhao Yihong, Zhu Shenlin. Cleaner production process and application examples. Beijing: Chemical Industry Press, 2002. Bu 3. Qi Enze Wu Hao. Green Chemistry and Chemical Industry. Beijing: Chemical Industry Press, 20009-20. Gong Changsheng, Zhang Keli. Green Chemistry Chemical Technology.

Jiang Bin, Wang Dawei, Feng Wei, et al. Direct Synthesis of Dimethyl Carbonate from Carbon Dioxide and Methanol. Chemical Development, 2(1)3, 22(1)43*45. Zhu Xian. Green chemical process. Beijing: Chemical Industry Press, 2001.151-154. Hong Liangzhi, Tu Jianjun. Research Progress of Double Metal Cyanide Catalysts . Synthetic Chen Yongfu, Jin Zhaosheng. Development and Research of Catalytic Synthesis of Propylene Glycol Ether by Liquid - Solid Phase Fixed Bed . Advances in Fine Petrochemicals, 2(1)01(1):9-15. Beijing: Chemical Industry Press 2002. Widely used, can also be used as organic synthesis intermediates. Propylene glycol ether published more than 20 papers.