TH41012B - Process for the production of alkyl nitrite - Google Patents

Abstract

DC60 (16/11/41) Alkyl nitrite can be produced on an industrial scale with high efficiency and low by-product yield by a process in which a feed gas containing nitrogen oxides is introduced into alkyl alcohol liquid in a column distillation reactor while circulating liquid fractions produced in the reactor and containing alkyl alcohols, through a circulation path that includes the bottom of the reactor and a cooler to remove the reaction heat generated intensely in the reactor, and while controlling the weight ratio of circulating liquid fractions to the total alkyl alcohols fed into the reactor to 50:1 to 200:1, the molar ratio of alkyl alcohols fed into the reactor and present in the circulating liquid fractions to nitrogen oxides in the feed gas to 20:1 to 150:1, and the amount of alkyl alcohols in the liquid fractions to 15 to 60% by weight; The resulting gas fraction containing the target alkyl nitrite is collected from the reactor. Alkyl nitrite can be produced industrially with high efficiency and low byproduct yield by a process in which a feed gas containing nitrogen oxides is introduced into the alkyl alcohol liquid in the reactor distillation column while the liquid fraction produced in the reactor and containing the alkyl alcohols circulates through a circulation path that includes the bottom of the reactor and a cooler to remove the reaction heat generated intensely in the reactor, and while controlling the weight ratio of the circulating liquid fraction to the total alkyl alcohols fed into the reactor to 50:1 to 200:1, the molar ratio of the alkyl alcohols fed into the reactor and present in the circulating liquid fraction to nitrogen oxides in the feed gas to 20:1 to 150:1, and the amount of alkyl alcohols in the fractions. The liquid fraction reaches 15 to 60% by weight; and the resulting gas fraction containing the target alkyl nitrite is collected from the reactor.

Claims (12)

1. The process for the production of alkyl nitrite consists of the following steps: (1) feeding alkyl alcohol liquid into the upper part of the distillation column reactor where the upper part is connected to the lower part which has a bottom section where the alkyl alcohol-containing liquid fractions are accumulated, while allowing the fed alkyl alcohol liquid to flow down through the upper and lower parts; (2) circulating the alkyl alcohol-containing liquid fractions through a circulation path through which the bottom liquid fractions are drawn out from the bottom section of the distillation column reactor, the drawn liquid fractions are cooled, and subsequently the cooled liquid fractions are returned to the upper part of the lower part of the distillation column reactor, thus causing the returned liquid fractions to flow down through the lower part of the distillation column reactor; (3) introducing a nitrogen oxide-containing feed gas into the lower part of the distillation column reactor. (4) The discharge of the resulting alkyl alcohol-containing liquid fraction from the distillation column reactor where (a) the total volume of liquid fraction circulating through the bottom of the distillation column reactor is controlled to a level 50 to 200 times the total volume of alkyl alcohol fed into the distillation column reactor; (b) the total molar volume of alkyl alcohol fed into the distillation column reactor and the alkyl alcohol present in the liquid fraction circulating through the bottom of the column reactor. (c) the distillation was controlled in a molar ratio of 20:1 to 250:1 to the molar amount of nitrogen oxides present in the feed gas fed into the bottom of the distillation column reactor; and (c) the amount of alkyl alcohols in the bottom liquid fraction accumulated in the bottom of the distillation column reactor was kept at 15 to 60% by weight. 2. The process for the production of alkyl nitrite as claimed in claim 1, whereby a circulation phase is performed by drawing the bottom liquid fraction from the bottom of the distillation column reactor through a tube, cooling the drawn liquid fraction through a cooler, and returning the cooled liquid fraction to the top of the bottom, in which case the returned liquid fraction flows down through the bottom of the distillation column reactor. 3. The process for the production of alkyl nitrite as claimed in claim 1, in which the circulation phase, the extracted liquid fraction is cooled to a temperature range from 0°C to 50°C and below the initial temperature of the bottom liquid fraction by 3 to 20°C. 4. The process for the production of alkyl nitrite, as proposed in Reputation 1, in which a portion of the liquid fraction drawn from the bottom of the distillation column reactor is removed from the circulation path, and the remaining liquid fraction that was drawn out is cooled and subsequently returned to the top of the bottom of the distillation column reactor. 5. The process for the production of alkyl nitrite as claimed in claim 1, in which a gas-liquid reaction of nitrogen oxide with alkyl alcohol is initiated at temperatures of 0 to 100°C. 6. The process for the production of alkyl nitrite as proposed in claim 1, in which the total volume of liquid fraction circulating through the lower part of the distillation column reactor is controlled to a level 70 to 160 times the volume of alkyl alcohol fed into the distillation column reactor. 7. A process for the production of alkyl nitrite as proposed in Reputation 1, where the feed gas contains nitrogen monoxide in an amount of 50 molar or more from the total molar amount of nitrogen oxides present in the feed gas, and also contains oxygen molecules in the amount of 0.02 to 0.25 mol/mol of nitrogen oxides. 8. The process for the production of alkyl nitrite as proposed in claim 1, in which, at the feed stage, a liquid alkyl alcohol cooled to a temperature of -15°C to 30°C is fed into the top section of the distillation column reactor, and subsequently allowed to flow down through the upper and lower sections of the distillation column reactor. 9. The process for the production of alkyl nitrite as proposed in Reputation 1, where the feed gas for the distillation column reactor is supplied from the process for the production of alkyl oxalate, in which carbon monoxide and alkyl nitrite react with each other in the presence of a catalyst in the reactor, to produce a fractional gas containing dialkyl oxalate; the resulting fractional gas is fed into an adsorption column, where the fractional gas is brought into contact with an adsorption fluid containing alkyl alcohol, to prepare a condensed liquid fraction containing dialkyl oxalate adsorbed in the alkyl alcohol adsorption fluid and an uncondensed gas fraction containing alkyl alcohol vapor and nitrogen monoxide gas; The uncondensed fractional gas is released from the adsorption column and fed, as feed gas, into the distillation column reactor to produce alkyl nitrite-containing fractional gas. 10. The process for the production of alkyl nitrite as claimed in claim 9, in which the liquid fraction produced in the adsorption column is fed into a distillation apparatus, a distillation column, to collect the filtered dialkyl oxalate. 11. The process for the production of alkyl nitrite as proposed in claim 9, in which alkyl nitrite-containing fractional gas is discharged from a distillation column reactor and fed into a column reactor for the production of dialkyl oxalate-containing fractional gas. 12. A procedure for the production of alkyl nitrite as claimed in Reputation 1, where alkyl alcohols are methyl alcohols and alkyl nitrite is methyl nitrite. (Reputation 12, 4 pages, 2 figures)