SU490278A3 - The method of obtaining silver catalyst - Google Patents

Description

4 Table 1

Carrier

Note: Including 0.27 wt. % - barium oxide.

Solutions for the preparation of catalysts are prepared as follows.

I. Silver oxalate, ammonia, ethanolamine. Freshly prepared silver oxalate precipitate from aqueous solutions of nitrate

silver and potassium oxalate (salts correspond to the degree of purity of the category chd) 25 times washed with deionized water, then dissolved in an aqueous solution of ammonia with a concentration of 30 wt. % that privot a b d d c a 2

It leads to the preparation of a solution of Ag (KNZ) 2 2C2O4 L with a concentration of 1.43 mol. % In conclusion, this solution is mixed with ethanolamine in such a way that its concentration is 10 vol. %, which corresponds approximately to the content of about 0.5 mol of ethanolamine per 1 mol of silver.

L. Oxylate silver, ammonia, ethanolamine. Proceed as indicated in the preparation of solution 1 with the difference that the molar ratio between silver and ethanolamine is 1: 1.

III.Oxalate silver, ammonia, ethanolamine. Proceed as indicated in the preparation of solution I with the difference that the molar ratio between silver and ethanolamine is 1: 1.5.

IV.Oxalate silver, ammonia, ethanolamine. Proceed as indicated in the case of preparation of solution I with the difference that the molar ratio between silver and ethanolamine is 1: 2.

V. Silver oxalate, ethylenediamine, ethano. Alamine. A pure solution of silver oxalate, prepared as indicated for solution I, is dissolved in an aqueous solution containing 4.2 mol / L of ethylenediamine (EN) with the same calculation, to obtain a solution containing 2.05 mol (Ag23H) C2O4 to 1 l. Then to this solution. Also, in the case of solution I, ethanolamine is added in an amount of 10 vol. %

VI. Silver carbonate, ethylenediamine, ethanolamine. Silver carbonate is dissolved in an aqueous solution of ethylene diamine in such a way as to obtain a solution containing 4.5 moles of silver per liter. Moreover, a molecular ratio between ethylenediamine and silver was obtained, ranging from -1.2-1.1. Then 0.4 mol of ethanol is added per 1 mol of silver. The prepared solution contained: sting 4.0 mol of silver per 1 liter.

VII.Lactic silver, ethylene diamine, ethanolamine.

VIII. Acetic silver, ethylenediamine, ethanolamine.

IX.Glucinate silver, ethylenediamine, this: Nolamin.

X. Sodium silver, ethylene diamine, ethanolamine.

Solutions VII-X were obtained, like solution VI, only the silver salt was replaced.

XI.Silberic silver, ammonia, these .lenediamine. The method of obtaining is the same as for

solution I, but instead of 10 vol. % ethanolamine used 10 wt. % ethylenediamine.

In the proposed catalysts, silver is in the form of almost semicircular particles, which are uniformly distributed over the surface. Silver particles are especially strongly bonded to the surface, as with repeated free falls and shaking.

Example 2. Comparison of catalysts in the case of the preparation of ethylene oxide in their presence.

All catalysts described in Example 1 were tested for use in the synthesis of ethylene oxide under industrial conditions.

In tests, the direct oxidation of ethylene to ethylene oxide by means of molecular oxygen is carried out in the reactor as a single tube under the conditions of a single pass of reactants (single pass method). However, the composition of the gas mixture is selected so that it corresponds to the composition for large installations with a recirculation system. The permeable gas mixture is maximally simplified in composition and contains ethylene and air.

The tube used is so small that rings of size 8x8 mm, on which the catalyst was applied, had to be ground to the size of particles passing through a mesh of mesh. The tube had an internal diameter of about 0.5 cm and a length of about 12.5 cm. The amount of nitride in the catalyst tube was 3.5 g; The reaction conditions are as follows:

Pressure abs. atm15

Productivity, hour 2360

The ethylene content in the feed mixture, mol. %thirty

Ratio between ethylene and oxygen in the feed mixture 3,751 Content: chlorine in the feed mixture, weight. parts per million by weight part 2

When assessing the applicability of catalysts, the selectivity of the formation of ethylene oxide as the target product from reacted ethylene or oxygen, hereinafter referred to as S {Et) or S (O2), was taken as the most important indicator.

Percentage mixing in a single pass is designated C (Et) and C (O2).

Percentages characterizing selectivity have different meanings. This is explained by the fact that, in practical terms, unreacted substances in the prevailing amount are returned to the reaction zone for reuse and thus contribute their share in the formation of the target product.

The values of S (Et) and S (O2), as well as C (Et) and C (O2), are interrelated for a given ratio between ethylene and oxygen in the composition of the supplied gas.

Substitution (conversion) is the quantity that determines production capacity. Due to the fact that practically all the ethylene oxide formed is released from the composition of the reaction mixture by washing with water, the amount of ethylene oxide produced in 1 hour can be determined as follows.

The amount of ethylene entering the reaction zone in 1 hour is multiplied by