DE2037975C - Process for the production of nitrous oxide - Google Patents

Description

The invention relates to a method for producing nitrous oxide by oxidizing solutions of hydroxylamine or hydroxylamine salts.

Various methods of producing nitrous oxide are known. Nitrous oxide can be im technical scale through thermal decomposition of ammonium nitrate according to reaction

NH ₄ NO ₃ - * N ₂ O + 2H ₂ O,

by burning ammonia with oxygen at a temperature of 200 to 500 ° C over suitable catalysts, e.g. B. Mn " ₂ , Fe ₂ O ₃ , BiO ₃ , or by the action of hydroxyl chloride or hydroxyl amine sulfate on aqueous sodium nitrite solution can be kept.

! A major disadvantage of this process is that it is not pure, but predominantly with By-products, such as nitrogen oxides, nitrogen and oxygen, contain contaminated nitrous oxide. in the With a view to its application, particularly in medicine, the nitrous oxide thus obtained must then be subjected to arduous cleaning procedures.

The object of the invention is to overcome the disadvantages of the previously known methods by creating a method to overcome what nitrous oxide allows to obtain in a greater purity.

It has been found that pure nitrous oxide can be obtained by oxidizing solutions of hydroxylamine or of hydroxylamine salts can be produced by nitrogen oxide, higher nitrogen oxides and / or oxygen with the hydroxylamine or salts thereof in the presence of an acid-resistant one Supported catalyst from the Plat.Hmetall group converts.

As a catalyst from the platinum metal group, in particular platinum, z. B. in an amount of 15 ° / ,, on acid-resistant carrier, / .. H. Molecular sieves, graphite, activated carbon, RuU,! Ini'ewendel.

To carry out the basic process, the catalyst /. I). introduced into the llydroxyluniinsiilfi t-Liisiiiig and with simultaneous mixing .nitrogen monoxide into the reaction 2NH ₂ OH + NO, + NO

Cat.

2N ₂ O! -3H ₂ O,

while with pure nitric oxide the reaction proceeds as follows:

2NH ₂ OH + 4NO

Cat.

3N ₂ O + 3H ₂ O.

A particular advantage of the manufacturing process according to the invention is that no additional Purification of the final product is required because you get the nitrous oxide straight away in pure state receives. The production costs of nitrous oxide are low in this process, mostly cheap raw materials such as nitric oxide and oxygen are used.

With the aid of the method according to the invention one can also do that according to other known methods purify nitrous oxide produced by simply contaminating it with higher nitrogen oxides or oxygen Nitrous oxide used for the implementation. The implementation of the nitrous oxide Impurities such as higher nitrogen oxides or oxygen lead to an enrichment in nitrous oxide. Pure nitrous oxide which can be used for medical purposes is discharged from the reaction medium. The reaction with oxygen takes place according to the following equation:

2NH, 0H + O,

Cat.

N ₅ O + 3 H ₂ O.

The process according to the invention can be carried out continuously or batchwise.

example 1

1 m ^{3 of} a solution of a hydroxylamine salt with a content of 30 g of NH ₂ OH /! and 660 g of catalyst, introduced in the form of platinum in an amount of 15% ^a uf graphite. The solution is ^{heated up to 50 °} C., whereupon nitrogen oxide is introduced with mixing at a rate of 10 m ³ / hour. At the same time, 7.5 m ^{3 of} N ₂ O / hour are increased. The nitrous oxide obtained is compressed after the water has been separated off and filled into steel bottles. After 3.5 hours, the solution is supplemented with hydroxylamine, which was obtained by reducing NO with hydrogen. This procedure is repeated at equal intervals.

Example 2

The process can also be carried out continuously will.

In this case, 1 m ^{1 of} hydroxyl

amine solution with a content of 10 g NH ₂ OH / 1 and 660 g catalyst, in the form of platinum in a menri; of 15% on graphite. The solution is ^{heated up to 50 °} C., then at this temperature 245 l / hour of hydroxylamine _{solution with a content of 30 g of NH 2} OH / 1 and 10 m 'NO at 10 m ³ / hour are introduced into the reaction vessel with constant mixing , and nitrous oxide is simultaneously discharged from the reaction vessel at a rate of 251 l / hour.

The post-reaction solution is with hydroxylamine, which in another apparatus by reduction is made of NO with hydrogen, and then hydroxylamine solution is added to the reaction vessel in which nitrous oxide is produced, introduced.

Example 3

1 m ^{3 of} hydroxylamine sulfa solution with a content of 10 g of NH ₂ OH /! and 660 g of catalyst, introduced in the form of platinum in an amount of 15 ° / ₀ to graphite. The solution is ^{heated to 95 °} C., whereupon oxygen is introduced with mixing at a rate of 10 m ³ / hour and 9.6 m ³ N ₂ O / hour is obtained at the same time. After separating out the water, the nitrous oxide is compressed and filled into steel bottles.

After 180 minutes, the solution is treated with hydroxylamine, which is obtained by reducing NO with Hydrogen was obtained, replenished.

B e i s ρ i e 1 4

In a reaction vessel equipped with a stirrer and heating jacket, 1 m ^{3 of} hydroxylamine sulfa solution containing 10 g of NH ₂ OH /! and 660 g of catalyst in the form of platinum in an amount of 15 ° / ₀ introduced on graphite. The solution is ^{heated to 40 °} C., whereupon oxygen is introduced at a rate of 10 m ^{3 / hour with mixing and 9.6 m 3} N ₂ O / hour is obtained at the same time. The di nitric oxide becomes grain after separation of water

ao primed and filled into steel bottles The solution is obtained after 200 minutes with hydroxylamine by reducing NO with hydrogen » has been added.

Claims (3)

Patent claims: 1. Process for the production of nitrous oxide by oxidation of solutions of hydroxylamine or the salts thereof, characterized in that that nitrogen oxide, higher nitrogen oxides and / or oxygen with the hydroxylamine or the salts thereof in the presence a catalyst from the platinum metal group arranged on an acid-resistant support implements. 2. The method according to claim 1, characterized in that it is carried out at a temperature between 90 ⁰ C Obis. 3. The method according to claim 1 or 2, characterized in that it is with hydroxylamine or hydroxylamine salt Lösunge.i a concentration of 5 g NH ₂ OH /! up to 175 g NH ₂ OHI, preferably 50 g NH ₂ OMZl, is carried out. medium introduced, with pure nitrous oxide discharged and, optionally after separating out water, made up in the usual way, for. B. is compressed and filled in steel bottles.
It is advantageous to run the process at a higher temperature, e.g. P. at 50 ⁰ C to perform. For the production of nitrous oxide, it is not necessary to use pure nitrogen monoxide as the starting material. The nitric oxide can with higher ίο nitrogen oxides, z. B. N ₂ O ₃ , NO ₂ , N ₂ O ₅ , be contaminated, since then the method according to the invention runs according to the following equation: