Method of Producing Allylacetate

The present invention relates to producing unsaturated esters of carboxylic esters and more particularly to a method of producing allylacetate which can be used as a starting material in chemical and petrochemical industries for preparing various products of organic synthesis as well as a range of polymer materials.

Known in the art is a method of producing allylacetate by oxyacetylation of propylene with acetic acid and oxygen in a gaseous phase at a temperature from 150.degree.-250.degree. C under a pressure of 1-10 atg in the presence of a catalyst containing a palladium salt, for example, palladium acetate, and activators on a support, mainly, aluminium oxide or silicic acid.

Salts of bismuth, copper, vanadium, sodium, potassium and other metals are used as activators. The process is carried out both in a stationary and in a fluidized bed of a catalyst.

The yield of allylacetate per litre of a catalyst per hour is 430-495 g/1.hr when the process is run in a stationary bed of a catalyst.

In case the process is conducted in a fluidized bed of a catalyst, the yield of allylacetate is 790 g/l.hr.

The principal disadvantage of the known methods is a low yield of allylacetatate per litre of a catalyst per hour due to poor efficiency of the catalyst.

The object of the invention is to increase the yield of allylacetate.

Said object is accomplished in a method of producing allylacetate by oxyacetylation of propylene with acetic acid and oxygen in a gaseous phase at a temperature from 150.degree.-250.degree. C under a pressure of 1-10 atg in the presence of a catalyst containing a palladium salt and activators on a support, according to the invention, as a palladium salt use being made of a complex salt thereof, namely, tetraamonium palladium acetate of the formula / Pd(NH.sub.3).sub.4 /(CH.sub.3 COO).sub.2.

To increase the yield of allylacetate it is expedient to use a catalyst containing 1-10 wt % of tetraammonium palladium acetate.

To increase the catalyst efficiency it is preferable to use a mixture of zinc acetate and sodium acetate with copper acetylacetonate or copper acetate as activators.

The proposed method is realized as follows.

A vapour-gas mixture of propylene, acetic acid, and oxygen is passed through a reactor loaded with a catalyst at 150.degree.-250.degree. C and 1-10 atg. Said vapour gas mixture is condensed after leaving the reactor with subsequent isolation of the desired product.

The process is run in a stationary bed of the catalyst.

The catalyst contains tetraammonium palladium acetate in an amount of 1-10% of the total weight of the catalyst, 2.5 wt% of copper acetylace tonate or copper acetate, and 10 wt% of a mixture of zinc and sodium acetates in a ratio of 1:1 on a support, aluminium oxide thermally treated at 900.degree. C being used as the support.

The catalyst is prepared in the following way. A 20% solution of NH.sub.3 is added to an aqueous solution of tetraammonium palladium acetate up to pH = 12. The solution temperature is raised to 40.degree.-50.degree. and then copper acetylacetonate or copper acetate, sodium acetate, and zinc acetate are dissolved in succession in said solution at 40.degree.-50.degree. with stirring. The impregnation of aluminium oxide with the resulting solution is performed at 50.degree. C. The support is kept in said solution for 4 hours, after which excess solution is decanted and the wet catalyst is dried at 85.degree.-90.degree. under a residual pressure of 300-350 mm Hg to a moisture content of 1%.

The use of tetraammonium palladium acetate as the main component of the catalyst increases the yield of allylacetate per litre of the catalyst per hour up to 2,180 g/1.hr due to enhancing the catalyst efficiency.

For a better understanding of the present invention specific examples of realizing the proposed method are given hereinbelow by way of illustration .

250 ml of a catalyst containing 2.0 wt % of tetraammonium palladium acetate, 2.5 wt % of zinc and sodium acetates in a 1:1 ratio deposited on aluminium oxide are put into a reactor. A vapour-gas mixture containing 3,000 nl/hr of propylene, 200 nl/hr of oxygen, and 800 g/hr of acetic acid is passed through the catalyst at 210.degree. C under 5 atg. The vapour-gas mixture leaving the reactor is condensed and rectified. The yield of allylacetate is 1,435 g per litre of the catalyst per hour.

250 ml of a catalyst containing 10.0 wt % of tetraammonium palladium acetate, 2.5 wt % of copper acetylacetonate, and 10 wt % of a mixture of zinc and sodium acetates in a 1:1 ratio deposited on aluminium oxide are put into a reactor. A vapour-gas mixtureof propylene, oxygen, and acetic acid in amounts as described in Example 1 is passed through the catalyst at 210.degree. under 5 atg.

The yield of allylacetate is 1,560 g per litre of the catalyst per hour.

250 ml of a catalyst containing 4.2 wt% of tetraammonium palladium acetate, 2.5 wt % of copper acetylacetonate, and 10 wt % of a mixture of zinc and sodium acetates in a 1:1ratio deposited on aluminium oxide are put into a reactor. A vapour-gas mixture containing propylene, acetic acid, and oxygen in amounts as described in Example 1is passed through the catalyst.

The yield of allylacetate is 1,135 g per litre of the catalyst per hour.

250 ml of a catalyst the composition of which is similar to that described in Example 3 are put into a reactor. A vapour-gas mixture containing 3,000 nl/hr of propylene, 200 nl/hr of oxygen, and 800 g hr of acetic acid is passed through the catalyst at 210.degree. C under 6 atg.

The yield of allylacetate is 1,845 g per litre of the catalyst per hour.

250 ml of a catalyst the composition of which is similar to that described in Example 3 are put into the reactor. A vapour-gas mixture having the composition similar to that described in Example 4 is passed through the catalyst at 210.degree. under 7 atg.

The yield of allylacetate is 2,180 g per litre of the catalyst per hour.

250 ml of a catalyst the composition of which is similar to that described in Example 3 are put into the reactor. A gas mixture containing 3,000 nl/hr of propylene, 200 nl/hr of oxygen, and 800 g/hr of acetic acid is passed through the catalyst.

The yield of allylacetate is 2,020 g per litre of the catalyst per hour.

250 ml of a catalyst containing 4.2 wt % of tetraammonium palladium acetate, 2.5 wt% of copper acetate, and 10 wt % of a mixture of zinc and sodium acetates in a 1:1ratio are put into a reactor.

A mixture of propylene, acetic acid, and oxygen in amounts similar to those described in Example 6 is passed through the catalyst at 190.degree. under 5 atg.

The yield of allylacetate is 1,180 g per litre of the catalyst per hour.

250ml of a catalyst containing 10 wt % of tetraammonium palladium acetate, 2.5 wt % of copper acetate, and 10 wt % of a mixture of zinc and sodium acetates in a 1:1 ratio is put into a reactor. A mixture of propylene, oxygen, and acetic acid in amounts similar to those described in Example 6 is passed through the catalyst at 210.degree. under 5 atg. The yield of allylacetate is 1,530 g per litre of the catalyst per hour.