megalomania
June 17th, 2003, 08:29 PM
mav
New Member
Posts: 5
From: Czech republik
Registered: MAY 2001
posted 06-25-2001 01:47 AM
--------------------------------------------------------------------------------
Abstract
A process for the continuous production of a propyl nitrate comprises keeping an aqueous reaction solution containing per 100 parts thereof between 30 and 45 parts nitric acid, at least 3 parts urea, and between 10 and 31.5 parts ammonium nitrate, all by weight, at a temperature between 105 DEG and 112 DEG C. (preferably 107-110 DEG C.) at atmospheric pressure, while maintaining this composition and the bulk by continuously introducing under the surface of the reaction solution nitric acid, the appropriate propyl alcohol, water and urea, at least the continuously added nitric acid and said propyl alcohol being introduced in separate streams, if desired already diluted with at least part of the continuously added water, at rates such that the molar ratio of added nitric acid to said propyl alcohol exceeds unity, and the continuously added urea being introduced in solution in at least one of the liquids streaming into the solution, continuously distilling away and condensing the resulting vapour mixture containing the propyl nitrate formed, continuously bleeding off a portion of the aqueous reaction solution of said composition, and separating the propyl nitrate rich layer of the condensate from the water rich layer. The aqueous reaction solution may be progressively formed by heating a solution containing per 100 parts between 30 and 45 parts nitric acid and at least 9 parts urea or less than 9 parts but greater than 3 parts urea together with between 5.3 and 2.3 parts ammonium nitrate for each part of urea short of 9 parts. Preferred nitric acid, urea and ammonium nitrate concentrations in the aqueous reaction solution are 45 per cent, 3 per cent and 22 per cent at 110 DEG C.; 40 per cent, 3 per cent and 14 per cent at 110 DEG C.; 40 per cent, 4 per cent and 18 per cent at 108 DEG C.; 32 per cent, 6 per cent and 13 per cent at 105 DEG C. The examples describe the preparation of n-propyl and isopropyl nitrate. Specifications 379,312, 540,050, 696,489 and 743,141 are referred to.
Isopropyl nitrate is prepared by the continuous distillation of a mixture of easily volatile products from a liquid reaction mixture which is at a temperature not below the boiling point of the azeotropic mixture of isopropyl nitrate and water and is formed from nitric acid and isopropyl alcohol and into which separate streams of nitric acid and isopropyl alcohol are introduced and in which a urea concentration sufficient to destroy nitrous acid is maintained, at least the isopropyl alcohol being introduced as a vapour below the surface of the liquid reaction mixture. At atmospheric pressure the reaction mixture should be at a temperature of not less than 80.5 DEG C. and preferably above 100 DEG C. The isopropyl alcohol vapour is preferably slightly superheated and preferably consists of an azeotropic mixture of isopropyl alcohol with water, such as that produced by boiling aqueous isopropyl alcohol of higher water content than the azeotropic mixture. The nitric acid concentration of the reaction mixture, including that combined with urea, is preferably from 35-60 per cent by weight, and that of urea is preferably maintained from start to finish at not less than 3 per cent by weight. The desired ammonium nitrate concentration in the reaction mixture is maintained by running a proportion of reaction mixture continuously to waste. Specifications 379,312, 540,050 and 696,489 are referred to.
New Member
Posts: 5
From: Czech republik
Registered: MAY 2001
posted 06-25-2001 01:47 AM
--------------------------------------------------------------------------------
Abstract
A process for the continuous production of a propyl nitrate comprises keeping an aqueous reaction solution containing per 100 parts thereof between 30 and 45 parts nitric acid, at least 3 parts urea, and between 10 and 31.5 parts ammonium nitrate, all by weight, at a temperature between 105 DEG and 112 DEG C. (preferably 107-110 DEG C.) at atmospheric pressure, while maintaining this composition and the bulk by continuously introducing under the surface of the reaction solution nitric acid, the appropriate propyl alcohol, water and urea, at least the continuously added nitric acid and said propyl alcohol being introduced in separate streams, if desired already diluted with at least part of the continuously added water, at rates such that the molar ratio of added nitric acid to said propyl alcohol exceeds unity, and the continuously added urea being introduced in solution in at least one of the liquids streaming into the solution, continuously distilling away and condensing the resulting vapour mixture containing the propyl nitrate formed, continuously bleeding off a portion of the aqueous reaction solution of said composition, and separating the propyl nitrate rich layer of the condensate from the water rich layer. The aqueous reaction solution may be progressively formed by heating a solution containing per 100 parts between 30 and 45 parts nitric acid and at least 9 parts urea or less than 9 parts but greater than 3 parts urea together with between 5.3 and 2.3 parts ammonium nitrate for each part of urea short of 9 parts. Preferred nitric acid, urea and ammonium nitrate concentrations in the aqueous reaction solution are 45 per cent, 3 per cent and 22 per cent at 110 DEG C.; 40 per cent, 3 per cent and 14 per cent at 110 DEG C.; 40 per cent, 4 per cent and 18 per cent at 108 DEG C.; 32 per cent, 6 per cent and 13 per cent at 105 DEG C. The examples describe the preparation of n-propyl and isopropyl nitrate. Specifications 379,312, 540,050, 696,489 and 743,141 are referred to.
Isopropyl nitrate is prepared by the continuous distillation of a mixture of easily volatile products from a liquid reaction mixture which is at a temperature not below the boiling point of the azeotropic mixture of isopropyl nitrate and water and is formed from nitric acid and isopropyl alcohol and into which separate streams of nitric acid and isopropyl alcohol are introduced and in which a urea concentration sufficient to destroy nitrous acid is maintained, at least the isopropyl alcohol being introduced as a vapour below the surface of the liquid reaction mixture. At atmospheric pressure the reaction mixture should be at a temperature of not less than 80.5 DEG C. and preferably above 100 DEG C. The isopropyl alcohol vapour is preferably slightly superheated and preferably consists of an azeotropic mixture of isopropyl alcohol with water, such as that produced by boiling aqueous isopropyl alcohol of higher water content than the azeotropic mixture. The nitric acid concentration of the reaction mixture, including that combined with urea, is preferably from 35-60 per cent by weight, and that of urea is preferably maintained from start to finish at not less than 3 per cent by weight. The desired ammonium nitrate concentration in the reaction mixture is maintained by running a proportion of reaction mixture continuously to waste. Specifications 379,312, 540,050 and 696,489 are referred to.