Cleaner Production Process Of Glyconitrile For Indigo Synthesis

Indigo has been revered as a dye for three thousands of years. Indigo could be obtained from aniline, through its conversion into N-phenylglycine. The N-phenylglycine(produced by the reaction of chloroacetic acid with aniline) gave indoxyl on fusion with alkali, and the indoxyl readily formed indigo by air oxidation. Due to the limitations of the technology and production process is difficult to avoid waste residue, waste water problems, serious environmental pollution, China indigo production and development of travel great restrictions. With the concept of environmental protection gradually win support among the people, the implementation of indigo scale and clean production process has be imperative.At present Chongqing Taifeng chemical company existing 6000 tons / year of indigo production capacity, such as realize the important raw materials of hydroxy acetonitrile’s own production, can simplify the production process, omit the long-distance transportation, dramatically reducing equipment investment and production cost, is conducive to further reduce the cost of indigo blue, enhance profitability, promoting market share rate increased further. From the existing products supporting and upgrading of, according to the resource conditions of hydroxy acetonitrile project, technical scheme, energy conservation and environmental protection and determined indigo production of raw materials of hydroxy acetonitrile process, so as to realize the transformation of indigo production process. The main conclusions of this paper are:1) the establishment of hydroxyl acetonitrile production process is in line with the national industrial policy, the demand for their products products chain, product profitability strong, the economic benefits significantly, and conducive to the promotion of technological progress and market competitiveness of downstream industries upgrade.2) the class hydrocyanic acid as raw material reactor technology, in the domestic leading level in the same industry, ammonia conversion rate reached 70%. Using dilute hydrocyanic acid gas and formaldehyde one pot conversion technology to produce hydroxyl acetonitrile production process, the project has the advantages of large scale, automation, the overall technical level of the leading domestic and international advanced.3) in energy saving and emission reduction, make full use of chemical reaction heat, chemical exhaust through advanced recycling device to generate steam for production; surplus steam for refrigeration, greatly reduces the power consumption, the energy consumption of the unit is in the advanced level in the same industry. The level of comprehensive utilization of project resources is high, and the circular economy is realized, and the policy guidance of the national development resources conservation oriented industry is in line with the policy.4) the waste gas can be discharged through the combustion process; the advanced technology and mature technology, the waste water discharged from the production process; the solid waste recycling.The advantage of this route is that with aniline acetonitrile as raw materials of synthetic indigo and indigo synthesis process of mixed alkali waste recycling all, can greatly reduce the indigo production process generated waste water, solid waste pollution. The technology for the production of domestic indigo opened the clean production process, greatly enhance the product competitiveness in the international market of indigo, with significant technical, economic and environmental benefits.