Research Progress and Application of Green Chemistry in Petrochemical Industry In May, 2003, the International Society of Engineering hosted the conference "Green Engineering: Definition Principles" in Sanding, USA, with the purpose of defining a set of principles of green engineering to guide engineers to design products and processes. Make it meet the needs of enterprises, government and society, including cost, safety, availability and environmental impact. Finally, Sandestin principle of engineer's working framework is published. The nine principles that engineers should follow to realize green engineering in an all-round way in engineering projects are: (1) consider the process and product as a whole, and evaluate the environmental impact by systematic analysis and integration; (2) protecting and improving the natural ecosystem, and also protecting human health and peace of life; (3) consider the whole ecological cycle in engineering activities; (4) Ensure the safe and benign input and output of all substances and energy as far as possible; (5) Minimize the consumption of natural resources; (6) Efforts should be made to reduce the generation of waste; (7) Formulate and implement engineering solutions according to local geographical and humanistic knowledge; (8) Innovating, creating and inventing technologies to achieve sustainable development, and creatively proposing engineering solutions based on traditional and mainstream technologies; (9) Let shareholders and society actively participate in the development of engineering solutions [2]. The chemical industry in the 20th century was based on mineral resources such as coal, oil and natural gas. Especially around the 1960s, the petrochemical industry developed rapidly, and at the same time, it also produced increasingly serious social problems such as resources and environment. Since 1990, the concept of green chemistry has risen rapidly and become the direction of sustainable development of chemical industry including petrochemical industry, which has attracted more and more attention from governments, enterprises and academic circles in various countries. In the field of petrochemical industry, some green chemical technologies have been continuously developed and applied, and even gradually become some emerging industries. This paper introduces some new progress of sustainable petrochemical technology. 1 the "atomic economy" of hydrocarbon oxidation reaction with hydrogen peroxide as oxidant is an index to measure how many raw materials atoms enter the product in chemical reaction. The standard not only requires saving raw material resources as much as possible, but also requires minimizing waste emissions. Oxidation of hydrocarbons is a very important reaction process in petrochemical industry. Because the product molecules with oxygen-containing functional groups are much more active than the raw hydrocarbon, the selectivity of such reactions is usually low, and some reactions need to be completed in multiple steps, which often produces a lot of waste. As a mild oxidant, hydrogen peroxide can carry out highly selective directional oxidation under the catalysis of some substances, and it is nontoxic. After the reaction, it is converted into harmless water, which greatly improves the "atomic economy" of the reaction, so it is regarded as a green oxidant [1]. Industrial application of 1. 1 titanium-silica molecular sieve for preparing cyclohexanone oxime by ammoximation of cyclohexanone. The preparation of cyclohexanone oxime is the core process of the mainstream production technology of chemical fiber monomer ε -caprolactam at present, which needs to be obtained by the reaction of cyclohexanone and hydroxylamine salt, but the preparation process of hydroxylamine salt is not "atomic economy", and it is seriously corroded and polluted. At the end of 1980s, EniChem Company of Italy put forward a new ammoximation process of cyclohexanone, that is, cyclohexanone, ammonia and hydrogen peroxide were directly synthesized by one-step "atomic economy" reaction under the catalysis of titanium silicalite molecular sieve. China Petrochemical Research Institute has also successfully developed a new ammoximation process of cyclohexanone with independent intellectual property rights, and cooperated with Baling Branch of China Petrochemical Company to complete a 70 kt/ a industrial test in August 2003. The conversion rate of cyclohexanone and the selectivity of cyclohexanone oxime are over 99.5%, and the utilization rate of ammonia is over 97%. However, in the traditional HPO process, the utilization rate of ammonia is less than 60%. At the same time, the new process avoids the production and use of nitrogen oxides and SOx(HPO), and makes the preparation of cyclohexanone oxime a clean production process. The traditional caprolactam production process with benzene as raw material has long process, complex process, large investment and high cost. Foreign companies such as DuPont, BASF and DSM have developed new technologies to produce caprolactam from butadiene [2,3], which can simplify the process and reduce the production cost. However, due to the huge investment in new equipment and high technical risks, it has not been industrialized so far. The new ammoximation process of cyclohexanone is suitable for the technical transformation of existing devices, which will make the process route of benzene to caprolactam more competitive. 1.2 New progress has been made in the new process of propylene epoxidation to propylene oxide. Since the birth of Ti-Si molecular sieve (TS- 1), the low-temperature liquid-phase oxidation process with hydrogen peroxide as oxidant has been continuously studied and developed. Another outstanding progress is the epoxidation of olefins with hydrogen peroxide to prepare epoxy, and the most important process is the epoxidation of propylene to prepare propylene oxide. Propylene oxide was prepared by epoxidation of propylene with hydrogen peroxide using TS- 1 as catalyst. The yield of propylene oxide is over 97% (calculated by propylene), and the yield by hydrogen peroxide is 87%. The by-products are mainly water and oxygen. In this process, the effective utilization rate of atoms reaches 76%. However, the effective utilization rate of atoms in the traditional two-step chlorohydrin production process is only 365,438+0%, which requires a lot of chlorine gas and lime, resulting in serious equipment corrosion and environmental pollution. As TS- 1 molecular sieve is expensive and difficult to separate from the product, other catalyst systems for propylene epoxidation are also under constant study, such as tin-loaded β zeolite [5], organic nitrogen complex Fe2 catalyst [6,7] and tungsten-containing metal cluster phase transfer catalyst [8]. Recently, BASF and Dow Chemical Company have made great progress in the development of propylene epoxidation process with hydrogen peroxide (HPPO) and completed their respective detailed evaluations. It is said that the advantages of HPPO method are short process, low investment and less land occupation, because it does not co-produce other products, especially small-scale production devices. Both parties plan to complete the pilot scale-up in the near future and start the construction of the first 300 kt/ a production plant, which is expected to be completed and put into operation in early 2007 [9]. In addition, Degussa and Uhde also plan to build a 60 kt/ a propylene oxide plant in Sasso, South Africa, using HPPO process. It is reported that [10] it has developed a special molecular sieve catalyst, and the amount of by-products can be minimized. Although the new process of propylene epoxidation uses expensive hydrogen peroxide as oxidant, the product yield can be greatly improved as long as the appropriate catalyst is used. At the same time, due to the simplification of the process, the process still has good technical and economic benefits, and the environmental advantages of this technology are expected to have an important impact on the propylene oxide industry. 1.3 The preparation technology of other organic oxygenates uses hydrogen peroxide as oxidant. Olefins, alcohols and carbonyl compounds can be oxidized to epoxides, alcohols and carboxylic acids with high selectivity, and metal catalysts, chlorine-containing oxidants and organic solvents can be avoided. The document [1 1] introduces the new technology developed by Kazuhiko Sato. Production of diol compounds by olefin oxidation. Using ordinary resin-supported sulfonic acid catalyst, different olefins and cyclic olefins can react with 30% excess hydrogen peroxide, and trans-1, 2- diol can be obtained with high selectivity and high yield, and hydroxyl-terminated olefins can also react in one step to generate trihydroxy compounds. Du Zexue et al. [12] developed a new suspension catalytic distillation process for the preparation of epichlorohydrin by epoxidation of chloropropene and hydrogen peroxide, with a reaction selectivity of over 98%, which is expected to replace the existing chlorohydrin production process. 2. Green chemical technologies such as phosgene and hydrocyanic acid, which replace toxic and harmful raw materials, are highly toxic substances. Because of their extremely active chemical properties, they are still widely used as chemical raw materials. However, if these chemicals are accidentally leaked during manufacture and use, it will cause incalculable casualties and environmental disasters. Therefore, the development of green chemical technologies such as replacing highly toxic phosgene and hydrocyanic acid with non-toxic and harmless raw materials has attracted attention [13]. A new process for producing isocyanate and polycarbonate instead of phosgene. At present, the processes for producing isocyanate instead of phosgene include: preparing isocyanate from primary amine and carbon dioxide or dimethyl carbonate, preparing isocyanate from primary amine and carbon monoxide by oxidative carbonylation, and preparing isocyanate from nitrobenzene and carbon monoxide by carbonylation. Some of these technologies are in the pilot stage, but the production cost is about 10% higher than that of the original phosgene method, which is uneconomical and needs to be improved. The process of producing polycarbonate from dimethyl carbonate instead of phosgene has been successfully developed. First, dimethyl carbonate reacts with phenol to produce diphenyl carbonate, and then it reacts with bisphenol A to produce polymer polycarbonate. Now the factory is under construction, and the production of dimethyl carbonate adopts methanol oxidative carbonylation to replace the traditional route of phosgene as raw material. South Korea's L G Chemical Company claims to have independently developed a new process for producing non-phosgene polycarbonate. Due to the simplified process, the investment can be reduced by 70%, and the operation cost and production cost of the device are obviously reduced. It can be seen that an economical and reasonable green process route can be found to replace highly toxic raw materials. 2.2 New Process for the Production of Methyl Methacrylate Following the industrialization of isobutylene oxidation and ethylene hydroformylation, people are still actively developing new processes to replace the traditional acetone cyanohydrin process with hydrocyanic acid as raw material. Direct oxidation of isobutane has been paid attention to because of its abundant resources and low price. The method includes two steps: isobutane is oxidized to produce methacrolein and methacrolein is oxidized to produce MMA. Because the reactivity of isobutane is lower than that of isobutylene, heteropoly acid catalyst with strong oxidation is usually selected. In recent years, it has been found that the introduction of elements such as V, Cu and Cs into phosphomolybdic heteropoly acid can promote the oxidation of methacrolein and improve the reaction yield. Moreover, adding P-Mo-V- Cu-Cs five-element catalyst and Mo-V composite oxide as additives to the slurry heteropoly acid catalyst of "MMA high selectivity catalyst" can increase the yield of MMA by two times, reaching more than 10%, showing a certain industrial application prospect. Lucite International has successfully developed its proprietary α-MMA technology, and plans to build the first set of 100 kt/ a MMA production equipment, which is expected to be completed and put into operation by the end of 2007. α- MMA is a two-step process. In the first step, ethylene, methanol and carbon monoxide undergo carbonylation reaction to produce methyl propionate. It is said that the palladium-based catalyst used has high activity, selectivity of 99 19%, good stability, mild reaction temperature and pressure conditions and little corrosion to equipment; In the second step, methyl propionate reacts with formaldehyde to generate MMA and water, and a proprietary heterogeneous catalyst [14] is adopted, so that MMA has high selectivity. This process greatly improves the economy of products, and it is the most important MMA production process developed in recent 30 years. MMA is an organic chemical raw material, which has a good development prospect in China. With the sustained high-speed growth of the national economy, its demand will continue to increase. China should carefully choose the green route in line with its national conditions and pay attention to overcoming its shortcomings. 3 Chemical reactions using environmentally friendly catalysts The core of petrochemical production technology is the catalyst. Although the consumption of catalyst is small, it may also cause great harm to the environment. Liquid acids such as sulfuric acid, hydrofluoric acid and aluminum trichloride are widely used acid catalysts, which are easy to corrode equipment, endanger personal health and community safety, and also produce waste liquid and waste residue to pollute the environment. At present, we should vigorously develop environment-friendly solid acid catalyst to replace liquid acid, and have achieved a number of industrialization results. In the alkylation of benzene with olefins, ethylbenzene was synthesized by gas phase method with ZSM-5 molecular sieve instead of aluminum trichloride, and cumene was synthesized by liquid phase method with USY or β zeolite or MCM-22 zeolite instead of aluminum trichloride. In addition, there is a new process of synthesizing long-chain alkylbenzene with solid acid instead of hydrofluoric acid. Using molecular sieve solid acid instead of catalysts such as aluminum trichloride and hydrofluoric acid has introduced a new generation of green technology for olefin alkylation, but the acid strength of molecular sieve catalyst is not as high as hydrofluoric acid and aluminum trichloride, and the distribution is not uniform enough, and the number of acid centers is small. Therefore, when using this kind of solid acid catalyst, the reaction temperature and pressure increase, and a small number of by-products and impurities increase. Therefore, the development of new solid acid catalysts has become a hot spot. Supported heteropoly acid catalyst is expected to overcome the above shortcomings and become a new generation catalyst; There are also some new catalytic materials under study, such as encapsulated liquid acids, nano-molecular sieve composites, ionic liquids and so on. China's research in this field has a certain foundation, so we should organize manpower, speed up development and strive for a leading position.