SU546609A1 - Method for preparing cycloalkanone oximes - Google Patents

Description

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This invention relates to an improved method for producing cycloalkano hydroxy which is used in the synthesis of lactams.

There are known methods for the production of cycloalkanone oximes by photochemical nitrosation of the corresponding cycloalkanes in an organic solvent, chloride, nitrosyl, in the presence of hydrogen chloride and / or concentrated sulfuric acid 1, 2.

There is also known a method for producing cycloalkanone oximes, which includes the steps of preparing: nirrosylsulfuric acid by the interaction of nitric oxide, nitrogen dioxide and sulfuric acid; nitrosyl chloride, nyTevi, decomposition of nitrosylsulfuric acid with hydrogen chloride and subsequent photochemical nitrosation of cycloalkane with nitrosyl chloride in carbon tetrachloride, with further recycling of hydrogen chloride released during photosynthesis of nitrosyl chloride 3J.

A disadvantage of the known method is the need to purify the hydrogen chloride returned to the stage of nitrosyl chloride production from nitric oxide formed during photosynthesis as a result of the skirt reactions of cycloalkanes. Thus, according to a known method, the waste gas mixture of nitrosyl chloride, hydrogen chloride, unreacted cycloalkane and nitric oxide, coming out of the photoreactor, is purified from nitric oxide by low-temperature freezing (from -60 to -50 ° C) from the nitrosyl II II mixture gas of hydrocarbon 20 % hydrochloric acid, followed by desorption of gaseous HC1 thereto in a complex technological scheme with high costs of heat and cold. Nitrogen oxide, released from the exhaust gas, contains hydrogen chloride, so it cannot be used, but must be discharged into the atmosphere.

In order to eliminate this drawback and simplify the technological process, nitrogen dioxide in an amount equivalent to the nitric oxide contained in it is added to the gas mixture obtained at the photochemical and nitrosation stage with recycling of the batch mixture to the nitrocell chloride stage.

In this case, a mixture of N0 and N02 in the nitrosyl chloride synthesis column is absorbed by sulfuric acid to form nitrosylsulfuric acid, and the latter, when interacting with hydrogen chloride, forms nitrosyl chloride, which is used in the cycloalkanes photonitrose stage.

The use of this method makes it possible to use nitric oxide, which is released during the photomonification of cycloalkanes, due to which the yield of cycloalkanone oximes on nitrogen-containing raw materials is almost 100%. In this way, the complex unit of regenerating hydrogen chloride can be reduced to completely eliminate the flow of heat and cold, completely eliminate gas emissions in atmosphere.

Example 1. After 13 l of cyclohexane at a temperature of 20 ° C and irradiation with a 500 W mercury-vapor lamp, a mixture of nitrosyl chloride and hydrogen chloride is bubbled in an amount of 150 h. The weight ratio of gases in a mixture of NOC1: HC1 is 1: 1.

170 g / h of oxime oil with a cyclohexanone oxime content of 60% (oxime yield by converted cyclohexane is 90%) and a gas mixture leaving the photoreactor in the amount of 84.5 g / h and having the following composition, g / h: NOC1 5 , 2, PS1 57.2, NO 5.2, cyclohexane vapor 16.9.

When 8 g / h of N02 is added to the specified gas mixture, and it is passed through a packed column, irrigated with a 25% solution of nitrosylsulfuric acid in sulfuric acid, a gas mixture of the composition, g / h, is obtained at the outlet of the synthesis column: NOC1 23 PS 34 , 5, i1clohexane vapors 16.9, traces of NO, N02.

When using this gas mixture with cyclohexane photonitrosation and cyclohexane, the yield of cyclohexanone oxime was nearly 100%, calculated as nitrogen in nitrosyl chloride.

Example 2. Analogously to example 1, a mixture of nitrosyl chloride and hydrogen chloride in the amount of 160 g / hour is passed through 13 l of cyclooctane. The weight ratio of gases in a mixture of NOC1: HC1 is 1: 1. 250 g / h of oxime oil with cyclooctanone oxime content of 59% are obtained (the yield of converted cyclooctane is 97%) and the gas mixture after the photoreactor of the following composition, g / h: NOC1 7.6; HC1 48.9; NO 1.8, cyclooctaine pairs 14.6. When NO2 is added to the gas mixture at 2.86 g / h and used in the NOC1 synthesis column and with cyclooctane on photonitrosation, as described in Example 1, the yield of cyclooctanone oxime is up to 100%, calculated on nitrogen at baseline. NOC1.

Example 3. Analogously to Example 1, nitrosyl chloride and hydrogen chloride in the amount of 60 and 30 g / h, respectively, are passed through 15 liters of a 30% -nagged solution of cyclododecane in carbon tetrachloride. 140 g / h of cyclododecanonoxne (oxime yield but cyclododecane converted to 94.5%) and a mixture of gases are obtained, leaving the photoreactor in an amount of 90.64 g / hour of the following composition, g / h: NOC1 8.3; HC1 57.34; N0 2.4; CCU 22.6.

Without adding an equimolar amount of N02 to the gas mixture, the yield of cyclododecanonoxy. MA on the nitrogen of the initial nitrosyl chloride is 91%. When NO2 was added to the gas mixture at 3.68 g / h and used as in Example 1, the yield of cyclododecanone oxime increased to 100%, calculated as nitrogen in NOC1.

F o rm - l inventions

A method of producing cycloalkanoneoxy., Comprising the steps of obtaining nitrosylsulfuric acid by the interaction of nitric oxide, nitrogen dioxide and sulfuric acid, nitrosyl chloride by decomposing nitrosylsulfuric acid, the stage of photochemical nitrozing of cycloalkane with nitrosyl chloride in carbon tetrachloride and recycling the generation of cycloalkane with nitrosyl chloride in carbon tetrachloride and recycling of the cycloalkane with nitrosyl chloride in carbon tetrachloride and recycling of the cycloalkane to nitrosyl chloride in a carbon tetrachloride nitrosyl sulfuric acid and recycling of the cycloalkane with nitrosyl chloride in nitrosyl sulfuric acid by the decomposition of nitrosylsulfuric acid characterized in that, in order to simplify the process, the whole gas mixture is subjected to recycling, preliminarily nitrogen dioxide in a quantity equivalent to nitric oxide.

Sources of information taken into account in the examination:

1. Author's certificate N ° 174629, M. Kl.2 With 07С 131/02, 1964.

2. The author's certificate number 328086, M. Cl.2 C 07C 131/02, 1970.

3. Technological regulations for the production of dodecalactam by the method of photochemical nitrosation of cyclodecodia, N ° 12480,

1971.