The present invention relates to a process for manufacturing isocyanates from an amine compound. The process comprises the steps of a) Providing chlorine; b) Providing carbon monoxide; c) Reacting said chlorine and said carbon monoxide for providing phosgene, the carbon monoxide being provided in an adjustable molar excess; d) Providing an amine compound and phosgenating said amine compound using said phosgene thereby providing said isocyanate; the process further comprises adjusting said adjustable molar excess, i.e. the molar excess of carbon monoxide, for adjusting the colour of the isocyanate.

Process for manufacturing isocyanates

In a process for safe production of phosgene (COCI 2 ) from carbon monoxide and chlorine according to the reaction scheme CO (g)+Cl 2 (g)−>COCI 2 (g) in a plant with a capacity of phosgene below 10 t/hr, the CO is produced on site from a feed stock based mainly on CO 2 . The plant preferably comprises a solid oxide electrolysis cell (SOEC) stack system producing CO for use together with chlorine in the phosgene synthesis. This way of producing phosgene is based on using primary raw materials for which escape concentrations above 1000 ppm or even above 10000 ppm or 10% will not result in any health risk.

A process for safe production of phosgene

FIELD: chemistry.SUBSTANCE: method includes the following steps: a) providing chlorine; b) providing carbon monoxide; c) reacting said chlorine with said carbon monoxide to obtain phosgene, wherein the carbon monoxide is fed controlled molar excess; d) providing an amine compound and phosgenation of said amine compound using said phosgene to obtain said isocyanate. Molar excess of carbon monoxide is controlled in order to control the colour of the isocyanate, wherein the molar ratio of carbon monoxide to chlorine at step c) lies in the range from more than 1.000:1.000 to 1.025:1.000 inclusively.EFFECT: method enables to obtain light-coloured di- and polyisocyanates of the diphenyl methane range, wherein the colour of the isocyanate can be controlled or maintained in an acceptable range.6 cl, 1 tbl, 7 ex

Method of producing isocyanates

Provided in the invention are a catalyst for preparing phosgene and a preparation method therefor, and a method for the preparation of phosgene and the comprehensive utilization of energy thereof. The preparation method comprises the following steps: 1) stirring and soaking activated carbon in a modifying solution, then adding dimethyltin dichloride and chromium oxide powders and carrying out a reaction, and then adding a nickel oxide fine powder and ultrasonically oscillating same to prepare a pre-modified activated carbon; 2) drying the pre-modified activated carbon; and 3) heating and calcinating the dried pre-modified activated carbon from step 2) to prepare the catalyst. Based on the preparation method, thin layers are formed on the surface of the catalyst by bonding chromium tin phosphate and chromium tin silicate with Ni by means of -O-Ni-O-, respectively, which can improve the high-temperature resistance and oxidation resistance of the activated carbon, and improve the safe and stable operation level of a device. The aim of integrated comprehensive utilization of energy is achieved by coupling phosgene production with an evaporation and concentration process of brine and using steam as a heat source for evaporation and concentration of the brine.

Catalyst for preparing phosgene and preparation method therefor, and method for preparation of phosgene and comprehensive utilization of energy thereof

PROBLEM TO BE SOLVED: To obtain colorless phosgene in a high yield by reacting chlorine with carbon monoxide reduced in the content of hydrogen in the presence of an activated carbon catalyst. SOLUTION: This method for producing phosgene comprises reacting chlorine with carbon monoxide having a hydrogen gas content of ≤6mol.% in an amount excessive by 1-30mol.% based on a stoichiometric amount in the presence of an activated carbon catalyst in an amount of 800-1300kg based on 1000m 2 /hr of the carbon monoxide. The carbon monoxide reduced in the hydrogen gas content is produced by bringing carbon monoxide having a hydrogen gas content of ≥6.0mol.% into contact with an adsorbent such as silica gel, calcium chloride or activated alumina or by heating the carbon monoxide in the presence of a catalyst such as copper-activated carbon catalyst or copper-manganese- activated carbon catalyst at 40-100°C to convert the hydrogen into water, and subsequently bringing the water-containing carbon monoxide into contact with an adsorbent. COPYRIGHT: (C)1998,JPO

重和中野

Papers

Production of phosgene

重和 中野

Papers

Production of phosgene

重和中野