SU882595A1 - Method of regeneration of manganese catalyst for paraffin oxidation - Google Patents

Description

one

The invention relates to the regeneration of catalysts from an oxidized mixture during the separation of a catalyst slurry and is intended to return manganese compounds to the process of paraffin oxidation.

There is a method for the regeneration of manganese compounds from sludge water, which takes place at the stage of separation of the catalyst sludge from the oxidized mixture by treating it with soda ash. As a result, a precipitate of manganese hydroxide and carbonate is formed, which is treated with sulfuric acid and a solution of manganese sulfate fl is obtained.

However, the use of soda ash and sulfuric acid makes this method expensive.

Closest to the present invention is a method for regenerating a manganese catalyst from an oxidized mixture by contacting it with an aqueous solution of sulfuric acid 5-36 N in one to three times the amount of stoichiometry to the metal. As a result, a manganese-containing precipitate is formed / which is separated after cooling the oxidized mixture by centrifugation or Filtration. The resulting precipitate is dissolved in water and then treated with an alkali solution, which results in manganese hydroxide and alkali metal sulfate. Manganese hydroxide precipitates and is separated from the alkali metal sulfate aqueous solution by filtration or centrifuge by G23.

ten

However, the contacting of the oxidized mixture with sulfuric acid at elevated temperatures contributes to the course of the tar tar reactions, which

The 15 subsequent stages will lead to an increase in resinous products in bottoms and, consequently, to a decrease in the yield of the main products. In addition, the use of excess

20 of sulfuric acid leads to the pollution of the oxidized mixture with it, which at the subsequent stage - prolific oxide will cause the formation of a sulphate-containing waste water, which

25 is biologically difficult to decompose and

requires the introduction of local cleaning. Neutralization of the resulting manganese sludge with alkaline agents requires costs and

This leads to the formation of sulphate-containing wastewater during the precipitation of manganese hydroxide.

The purpose of the invention is to simplify the regeneration process.

This goal is achieved in that according to the method of manganese catalyst regeneration, which involves treating the oxidized mixture with an acid, which uses formic acid or waste water containing formic acid, and treat it with an equivalent amount of manganese and subsequent separation of the manganese-containing sediment. .

Replacing the mineral acid with carbionic acid makes it possible to exclude sulfuric acid from the regeneration process of the manganese catalyst. Formic acid, being the strongest in the range of organic monocarboxylic acids (K 1.8. 10), interacting with the manganese salts of organic acids forms manganese formate. The formate has limited solubility and is precipitated, which is separated by filtration, centrifugation or decantation.

In order to prepare a catalyst based on manganese formate obtained in this way, the addition of alkaline agents is not required, and therefore leads to a reduction in costs.

The use for contacting wastewater containing formic acid, such as acidic water, of the washing unit for gases from oxidizing columns or condensate of the paraffin oxidation unit, greatly simplifies and reduces the cost of catalyst regeneration.

The method is carried out as follows.

An aqueous solution of formic acid, containing an equimolar amount of it with respect to manganese, is fed to the oxidized mixture for irrigation into a sludge settler, settled for 45 minutes, and the resulting manganese formate is separated by filtration, decantation or centrifugation.

The resulting manganese formate is used to prepare the catalyst.

Example 1. To a D kg of an oxidized mixture containing 1.2 g / kg of manganese, 4 g of an aqueous solution of 5b% formic acid are added, stirred at 60 ° C, settled for 45 minutes and centrifuged in a centrifuge at a speed of 3000 rpm for 5 min. In this case, two layers are formed: the top layer is an oxidized mixture and the bottom layer is a manganese formate precipitate. The upper layer is decanted, and the lower layer is collected and used to prepare a wax oxidation catalyst. To determine the manganese content, the oxidized mixture is washed with distilled water at a ratio of 1: 1 and the wash water is separated, and the manganese content in it is 0.00124 g / l, which indicates a high manganese recovery rate of 99%.

The resulting catalyst based on manganese formate showed high efficiency.

Example 2. To 1000 g of the oxidate containing 0.62 g / kg of manganese, 100 g of an aqueous solution of 2% formic acid are added, stirred and settled for 45 minutes. As a result, 2 layers are formed: the upper oxidate and the lower - an aqueous solution of manganese formate, which are separated in a separatory funnel. The amount of the aqueous layer is 105 g, the content of manganese in it is 6.19 g / l, the residual content of manganese in the oxidate is 0.0010 g / kg, the recovery rate of manganese compounds is 99.9%.

Reagent manganese formate is added to the aqueous layer to prepare a catalyst at the rate of 2.3 g for each 10 ml of the aqueous layer and 4.3 g of low molecular weight carboxylic acid sodium salts and used to oxidize paraffin.

Example 3. To 1000 g of the oxidate containing 1.2 g / kg of manganese, 30 g of acidic water containing 6.5% formic acid are added, mixed and separated according to example 2. The resulting aqueous layer (the amount of which is 32 g of manganese 39 , 99 g / l, the residual manganese content in the oxidate is 0.011 g / kg, the degree of manganese recovery (99.9%) is directed to the preparation of the catalyst. To this end, 1.46 g of manganese reactive formate and 4.3 g of low molecular weight carboxylic acid soda are added to the aqueous layer.

Example 4. To 1000 g of an oxidate containing 1.2 g / kg of manganese, 23 g of condensation water condensate from gases from the oxidation columns containing 9% formic acid are added and separated as in Example 1. The resulting aqueous layer (the amount of which is 24.4 g, the manganese content is 47.98 g / l, the residual manganese content in the oxidate is 0.011 g / kg, the degree of regeneration of 99.9% is directed to the preparation of the catalyst. To this end, 1.24 g of reactive manganese formate and 4.3 g of low molecular weight sodium soaps are added to the aqueous layer per each 10 g of aqueous layer, and are used to obtain the oxidation of paraffin.

Characterization of oxidate and acids obtained in the presence of a regenerated catalyst in examples 1-4, is shown in the table. Acid number, mg KOH / G 68.9 202.9 70.9 199.2 71.1 Essential number, kg KOH / G 48.0 45.0 47.0 46 46 46.8 Carbonyl number, mg KOH / G 9.3 10.4 7.9 8.2 7.8 Content of acids,% - 35.2

Comparing the quality of the oxidate and the acids obtained in the presence of a regenerated catalyst with the quality of the oxidate and acids of the existing production showed that the regenerated catalyst is not inferior in quality to the catalyst used in the existing production of synthetic fatty acids.

The proposed method allows to exclude sulfuric acid and alkaline agents from the process.

Application, for contacting with the oxidate wastewater containing formic acid, eliminates the cost of chemical reagents and greatly simplifies and reduces the cost of the method.

Claims (2)

1. Authors certificate of the USSR 212996, cl. B 01 J 23/92, 1965. 2. The patent of the USSR (582751, tel. C 01 G 45/00, 1975 (prototype). 200.5 77.0 203.7 76.0 201.4 45.9 46.3 45.2 46.6 8.5 7.7 8.2 7.7 8.0