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Shandong shuiheng Chemicals is anexperienced manufactory which focus on Polyacrylamide almost decade, we are Top 5 polyacrylamide exporter in China, and our brand named Chinafloc.
In 1954, American Cyanamid Company developed the first legally produced sulfate technology, industrial production. Since then, acrylamide production process has undergone two changes: the invention of the medium-term copper-catalyzed hydration 1970s, mid-1980s to develop a microbial production process. Sulfuric acid hydration process is complex, copper catalytic hydration reaction due to the addition contain small amounts of by-products; microbial production of monomers due to low impurity content, high activity, particularly suitable for the production of ultra-high molecular weight polyacrylamide, and therefore subject to respected. In relation to the microbiological method, legitimate part of the traditional methods of water and sulfuric acid copper catalyzed legitimate water.
Sulfate lawful prior to acrylonitrile below 100 ℃hydrolysis into acrylamide sulfate, and then give acrylamide (AM). By the beginning of the acrylamide homopolymerization prepared nonionic polyacrylamide, relatively simple products. Soon he developed a partially hydrolyzed with a base (after hydrolysis) anionic polyacrylamide.
Copper-catalyzed water legitimate use of acrylonitrile in the presence of a copper-based catalyst was prepared by hydration reaction of acrylamide, said method comprising the reaction system or a salt thereof having an active methylene group and an acidic group in one molecule appears and anionic acrylamide-containing solution with a weakly basic or a medially basic exchange resin. In the above hydration reaction, the formation of impurities is suppressed, and the catalyst activity was not affected, resulting acrylamide and used to make water soluble high molecular weight flocculant good.
Copper catalytic hydration of acrylonitrile can also be handled by at least two purification steps, first with a strong acid * acrylonitrile-exchange resin and then contacting the resin having a primary or secondary amino group or in contact with the activated carbon. Finally The resulting acrylonitrile is hydrated in the presence of a copper-based catalyst. Even with the general quality of acrylonitrile, which is also capable of producing high-quality acrylamide, and to further develop the polyacrylamide has a good water-soluble.
Copper-catalyzed water legitimate disadvantage is the need to recycle acrylonitrile, and separation of copper, waste of resources and energy; at the same time more side effects, is not easy to control, product purity is not high.
Microbiological method acrylonitrile, water and immobilized biocatalysts deployment into the hydration solution, separated after the catalytic reaction the spent catalyst can be obtained acrylamide product. Compared with the traditional legal copper-catalyzed water, which is characterized by: at normal temperature and pressure reaction equipment is simple, safe operation; a high conversion per pass, without separation and recovery of unreacted acrylonitrile; specificity of the enzyme allows high selectivity no side effects. When using J-1 strain, the reaction temperature is 5-15 ℃, PH value of 7-8, the reaction zone acrylonitrile concentration of 1% -2%. Acrylonitrile conversion was 99.99%, the selectivity of 99.98% acrylamide, an acrylamide reactor outlet concentration of approximately 50%; the amount of enzyme deactivated catalyst is discharged outside the system is less than 0.1% of the product; without copper separation section, the ion exchange without processing, the separation and purification operations greatly simplified; high product concentration, without mention rich operation, the whole process is simple, less investment in equipment, high economic production, in favor of small-scale production.
Microbiological method has the following specific Technology:
(1) the application of membrane technology microbiological method. The method includes the step of microbial cell culture,
Preparation of bacteria suspension weight, as biocatalyst with free cell hydration reaction of acrylonitrile were separated from the reaction of acrylamide hydrating fluid. Wherein the microfiltration membrane was washed with purified fermentation broth of bacterial cells to produce weight suspension, using an ultrafiltration membrane to separate the acrylamide hydration fluid and biological impurities. Production of acrylamide using the technology can significantly improve productivity and cell efficiency while reducing biological impurities hydration liquid products, good quality of acrylamide obtained high purity.
(2) microbial continuous catalytic method. The law produced by fermentation of propionic acid containing nitrile hydratase stick
Coli cell or a strain mutagenesis, followed by free cells or immobilized catalytic method Cell Assay acrylamide Acrylonitrile water, and then to give a high purity acrylamide.
(3) using a microbial catalyst washed by aqueous acrylic acid solution. The law first with the acrylic water
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