SU717033A1 - Method of preparing propionic aldehyde - Google Patents

Description

((54) METHOD OF OBTAINING PROPYOCAL ALDEHYDE

The invention relates to methods for producing carbonyl compounds. A method is proposed for the production of a tertiary aldehyde, which is widely used in organic synthesis, in the production of rubber vulcanization accelerators, in the manufacture of synthetic fragrant substances, etc. A known method of producing propionic aldehyde by isomerization of al, lilac alcohol at a temperature of 50,250 ° C and a pressure of 10 atm in an acetic acid medium in the presence of a catalyst — silicates with additions of palladium and gold up to 5% l-J. The features of the process are the use of allyl alcohol in mixture with water and acetic acid, which makes it difficult to separate the target product; conducting the process under pressure, the release of gaseous reaction products (CO, Hj,); expensive catalyst. There is also known a method for producing propionic aldehyde by isomerizing allyl alcohol at a temperature of 50 ° C on a skeletal nickel catalyst with respect to a catalyst and allyl alcohol 1: 2-1: 10 (by weight) with continuous distillation of the resulting propionic aldehyde. The yield of the target product is 92-98% of theoretical 2. However, when implementing this method, it is necessary to strictly observe the temperature conditions, in order to eliminate the possibility of aldol condensation, it is necessary to continuously distil off the target product, as well as use a large amount of catalyst, the regeneration of which is associated with certain difficulties. as by-products, 2-methylpentene-2-al-1 and propiol, a lovy alcohol, are formed. The aim of the invention is to simplify the process and increase its selectivity. It is proposed a method for producing propionates in a large scale by measuring allyl alcohol in the presence of a heterogeneous catalyst composition, wt.%: ZrOz4 AljOj or, 1-5

ZrOj0-1-1

AljOj / the rest of the pass of an allyl alcohol pair, in an inert stream, or by evacuating to 10-15 mm. Hg over the catalyst heated to 280ZOO C.

The process of isomerization of allyl alcohol to propionic aldehyde is usually carried out in a two-stage flow reactor with an inner diameter of 1.4 cm. Allyl alcohol vapors are passed through a bed of heated catalyst to 280-300 s in an inert-gas-g-carrier stream (nitrogen or helium) or allyl alcohol vapor is fed to the catalyst by evacuating the unit to 10-15 mm Hg.

The first stage of the reactor provides heating of allyl alcohol vapor to the SO-S, the second contacting with the catalyst at 280-300 ° C.

Catalysate containing 98% propionic aldehyde (GCM control) is collected in an ice-cooled receiver. The desired product is isolated from the reaction mixture by distillation. The yield of the target product 94-98% with a selectivity of 100%.

Example 1. In the reactor is placed 2 g of catalyst containing 4.% ZrOj and 96%, and pass vapors of allyl alcohol (80 g, 1.4 mol in a stream of inert carrier gas (nitrogen or gels) with a bulk velocity O, b h The temperature in the catalyst bed is 280-300 ° C. By distillation of the catalyzate, 78.4 g (98%) of propionaldehyde and 1.5 g of the starting allyl alcohol are isolated.

The inter-regeneration period of the catalyst is 150 hours, flushed with nitrogen. at 500 ° C.

 Example 2. The ocytaecT process is as in Example 1, however, a catalyst of the composition, wt.%, Is used:

Ni5

; ZrOj. 0.7

A1gOg94,3-94

Out of 80 g (1/4 mol) of allyl alcohol, 77 g (93.7%) of propionic aldehyde and 2.8 g of starting allyl alcohol are obtained. The catalyst is regenerated after 130 hours of operation by blowing air at 1 hour for hydrogen and then at 170–200 ° for 3 hours.

Example 3. The process is carried out as indicated in Example 1 or 2, however, allyl alcohol vapor falls on the catalyst by vacuuming the installation to 10-15 mmHg. From 80 g (1.4 mol) of allyl alcohol, 78.4 g (98%) of propionaldehyde and 1.5 g of starting allyl alcohol are obtained.

Claims (2)

Invention Formula  The method of producing propionic aldehyde by isomerization of allyl alcohol at an elevated temperature in the presence of a heterogeneous catalyst is different in that, in order to control the process and increase its selectivity, as a hetero catalyst. gene catalyst used catalyst mash composition, wt.%: ZrOi AljO-j rest or Ni.0,1-5 ZrOi0.7-1 Al2 Oj rest and the process is carried out by passing allyl alcohol vapor in a stream of inert gas or by evacuating to 10-15 mm Hg. Art. over catalyst heated to 280-ZOO C. Sources of information taken into account in the examination .one. Patent of Germany No. 1959776, .kl. C 07 C 47/02, published 1975.  2. USSR author's certificate No. 533586, cl. C 07 C 47/02, 1974 (prototype).