DE1667353A1 - Process for the preparation of a catalyst for the preparation of hydroxylamine salts - Google Patents

Description

DR. BERG DIPL.-ING. STAPF

PATENT APPROPRIATIONS B MUNICH 2. HILBLESTRASSE 2O

Dr. Berg Dipl.-Ing. Stopf, 8 Manchen 2, HilblestraBa 20

Zaklady Azotowe im.P. iindera i-rzedsiebioEStwo Panotv / owe Kharkov, Poland

Your reference Our reference date

PIb 67 353.3-41 ■ "■. ^{J: l}

Attorney's file 16 801

Method for lieratstellung a catalyst for the Manufacture of Hydroxyiarnine Salts.

Me i! Irrinduni {botriffb a Terfahron aur production e Lneu aas platinum and 1.'r. ^: i /; er ;; loi'fen in the form of graphite,

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BATH ORIGINAL

Activated carbon or carbon black existing catalyst for the syn-: thesis of hydroxylamine salts. from nitrogen oxide and hydrogen.

On the yield of the process for the preparation of hydroxylamine salts as well as the composition of the Bach reaction solution has the quality of the catalyst used, which in turn depends on its manufacturing process, has an extraordinary influence. '■

A well-known process for production and regeiicration A special catalyst for the production of hydroxylamine salts has been disclosed in DBR Patent 1,068-037 described. In this process, the reduction of tetravalent platinum compounds in a two-step process in the presence of substrates such as graphite, activated carbon or soot. In this procedure, see the first reduction stage to divalent platinum, selective reducing agent (sodium dithionai; or derivatives of sulfoxylic acid) and in the second reduction stage, in which divalent platinum is converted to metallic platinum, Formic acid, hydrazine or formaldehyde application.

The first reduction stage is at a concentration of 300 1 of the reaction solution per 1 kg of platinum carried out,

during the second reduction stage at a concentration of 105 1 of the reaction solution per 1 kg of de's platinum is carried out. As a reaction solution, a solution is to be considered, which by mixing all during the reduction ingredients used was obtained. This procedure is cumbersome because it requires compound operations that are followed by a two-step process Reduction are connected. The catalyst produced by this process has a low compartment part Activity of about 50 g MD / g platinum per hour and a relatively short standing time of about 2 hours amounts to.

The present invention addresses the drawbacks '' the previous procedure with the help of a simple

process for producing a catalyst for the production to reduce hydroxylamine salts *

According to the invention, this object is achieved by the reduction of platinum compounds in dilute solutions, whereby no less than 300 liters, for reasons of economy, preferably 600 liters of the reaction solution. 5 ° CMs + 70 ° C, preferably from 50 ⁰ C, with a fine pH value above 9.0, using .Formalin

BATH ORIGINAL

or hydrazine as a reducing agent will. In order to extend the service life of the catalyst, it is beneficial to use the reduction product of the action of hydrogen to expose to peroxide or gaseous oxygen.

The catalyst produced by the process according to the invention has proven particularly suitable in the synthesis of hydroxylamine. This catalyst is characterized by an increased activity at IQ ⁰ O of about 150 g ΗΌ / g platinum and hour, a long service life of about 3 months and a high specificity of 90; - 99 ⁰ A from ,, which means that 90 - 99 i ° of the nitrogen oxide are converted into hydroxylamine. .

Example 1 '

9.9 kg of finely powdered graphite, activated carbon or carbon black are mixed with 12 liters of aqueous solution of HgPtClg, which contains 100 g of Pt, and heated to a temperature of 80.degree. C. with constant mixing. Once this temperature has been reached, mixing is continued for 4 hours. Then 3 1 10% aqueous Pormalin solution are added dropwise to the mixture and then the dropwise addition takes place. of 5 1 potassium hydroxide solution (48 ■ $) in such a way that the temperature of the mixture does not exceed ^{50 0 C.}

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Immediately afterwards, when the whole amount of KOH is added dropwise, the mixture is diluted by adding 18.4 l of water, ^{stirred for 1 hour at room temperature and then for a further hour at a temperature of 55 °} C. The catalyst is filtered off , washed out with water and dried in an air or oxygen atmosphere.

The catalyst prepared according to the invention has an activity of about 150 g ΙΓΟ / g Pt per hour and a high specificity of 90 when used in the Hydroxylamin-Syntlie.se at a temperature "door of 4O ⁰ C - 99 ° to f , ie that 90 - 99 i ° of the nitrogen oxide are converted into hydroxylamine.

Example 2

The procedure is carried out as in Example 1, with the , Difference that after filtering off and washing through φ the product obtained is mixed with 50 l of water and exposed to hydrogen for two and a half hours then it is mixed with 50 l of water, which contains 5 g of HpOp contains, offset. The catalyst is in wet J'orm used. This catalyst behaves similarly in the synthesis process of hydroxylamine as in Example 1. Er is characterized by high selectivity and activity

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and has a long service life of around 3 months.

Example 3

The spent low activity catalyst -will subjected to regeneration. For this purpose, 1 kg of the catalyst is mixed with dilute aqua regia and the The resulting mixture is heated, the platinum going into solution. The mixture is neutralized with soda and the further processes as in example 1 and 2 continued.

Those produced by the process according to the invention or regenerated catalysts allow the production yield of the produced hydroxylamine salts to be increased s per unit volume of the apparatus and the reduction in the amount of platinum required and contribute to dai3 pure hydroxylamine salt solutions are obtained.

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Claims (1)

Claim. Process for the production of a catalyst consisting of platinum and support materials in the form of graphite, activated carbon or carbon black for the production of hydroxylamine salts from nitrogen oxide and hydrogen, the platinum being applied to the support by reducing IV-valent platinum compounds by means of a reducing agent, characterized in that the reduction process in dilute solutions when using not less than 300 1, preferably 600 1, of the reaction solution to 1 kg of the
platinum contained in the compound used, in the temperature range from -5 ° 0 to +70 ⁰ C, preferably at 30 ⁰ C, at a pH above 9 is carried out that formalin or hydrazine are used as the reducing agent, and then the Possibly exposing the reduction product to the action of oxygen or hydrogen peroxide. 10987 & / 1455 Today's documents (Art 7 § ί At ». 2 nk i sau 3 d ·· Changeurw © ·.«, 4 9.1 ^