Device for preparing isocyanate by pyrolyzing aminoalkyl esters

Abstract

The invention belongs to the technical field of organic chemical industry production, and relates to a device for preparing isocyanate by pyrolyzing aminoalkyl esters. A major structure comprises a pyrolysis reaction kettle, three tower columns, two H distilling heads and three receiving pots; the top part of the pyrolysis reaction kettle is communicated with the bottom of sieve plate tower columns by a tower body support; the top part of a lower sieve plate tower column is communicated with the bottom of an oblique H distilling head; the top part of the oblique H distilling head is connectedwith the bottom of a middle packing tower column; an outlet of the oblique H distilling head is respectively communicated with a product receiving pot; the top end of the middle packing tower column is communicated with the bottom end of a horizontal H distilling head; the top part of the horizontal H distilling head is communicated with the bottom of an upper packing tower column; an outlet of the horizontal H distilling head is communicated with a byproduct right receiving pot; and the top part of the packing upper sieve plate tower column and the product receiving pot are communicated witha cold trap respectively. The device has simple structure, reliable principle, easy control of operation and use, high efficiency, strong reaction selectivity and low manufacture cost.

Description

Technical field: [0001] The invention belongs to the equipment field of organic chemical production technology, and relates to a device for preparing isocyanate by pyrolyzing aminoalkanoate. Background technique: [0002] Organic isocyanates are an important class of compounds, and difunctional diisocyanates are widely used in polyurethane industry, coating industry, dyes and pesticides. Isocyanate compounds are usually produced industrially, which are obtained by phosgenation of organic amines. Although phosgene has a high selectivity, it is a very toxic gas that needs to be strictly controlled, and its leakage is unavoidable after a long period of preparation and use of phosgene. Therefore, countries are actively developing non-phosgene production of isocyanate. At present, there are many processes and equipment involved in the non-phosgene method of preparing isocyanate. Among them, the process that has an important influence and is easy to industrialize is aminoalkanoa...

AI Technical Summary

Problems solved by technology

[0003] There are many processes and equipment devices for preparing isocyanate by pyrolysis of aminoalkanoates reported in existing patents, but the focus of research is not on reaction equipment, but on catalysts or continuous reactions; in U.S. Patent US4349483, Harder et al. The quartz tube of shavings is pressurized and decomposed MDC in the reactor to obtain 76.5mol% MDI; while in U.S. Patent No. 4,547,322, Tomonari et al. use zinc or aluminum Raschig rings as fillers, and decompose MDC under pressure in a stainless steel vertical reaction tube to obtain MDI. The yield is 89.2%wt; These technologies all adopt tubular reactor pressurized reaction, product yield obviously improves but long-term service pipeline is easy to block, is not suitable for suitability for suitability for industrialized production

In the process of preparing isocyanate by aminoalkanoate pyrolysis reported in U.S. Patents US6639101, US5449817, US5326903, US5914428, etc., continuous pyrolysis process is adopted, and the concentration of aminoalkanoate in the reaction system is very low, generally only 0.1%~8 %, while the concentration of solvent and carrier used is as high as more than 92%. This continuous pyrolysis process equipment is complicated to operate, low in diester content, difficult to recycle monoester, high energy consumption, high cost of heat carrier recovery, and economically has no advantages. Difficult to achieve industrial scale production

Images