SU383274A1 - - Google Patents

Description

METHOD OF OBTAINING UNSATURATED COMPLEX ETHERS

CARBONIC ACIDS

12

This invention relates to an improvement in the process for the preparation of unsaturated carboxylic acid esters, which find various uses in the chemical industry, in the production of polymeric materials.

A known method of producing vinyl acetate and other unsaturated esters of acetic acid by gas-phase interaction (exchange decomposition) of olefins (C2- € 4), acetic acid and oxygen in hp, in the absence of palladium catalysts containing activators (alkaline or alkaline-earth salts of acetic acid) and carriers, preferably alumina.

The process is carried out by means of a catalyst: Zion1p1Ny1m catalyst, as well as, ki (P-shch0m catalyst layer.

In the fixed bed, the catalyst is applied in the form of tablets, in boiling water, in the form of spherical particles with a size of 0.02-0.08 mm.

The process temperature is 100-250 ° C, mainly, the pressure is 1-30 atm.

However, carrying out the process in a fluidized bed of a catalyst is complicated by the fact that the small size of the catalyst particles provides for special dust collectors and the additional separation of the target product carried along with the catalyst dust. Therefore, process improvement is of current industrial importance.

To simplify the process, a catalyst with a diameter of predominantly spherical particles of 0.1-0.5 mm is used. It is advisable to use silicic acid as a carrier.

As an activator of palladium catalysts isobator OBB, any known, for example, carboxylates, especially alkali and alkaline earth metal acetates or metallic copper, gold, zinc, cadmium, tin, lead, manganese, chromium, molybdenum, tungsten, uranium, iron can be used. , cobalt, nickel, niobium, vanadium, tantalum.

Various known carriers can also be used, for example silica gel, diatomaceous earth, silicic acid, diatomaceous earth, alumina, aluminosilicate, aluminum phosphate, iron, silicon carbide, spinel, asbestos or activated charcoal. This greatly reduces the power and number of dust collection devices.

In addition, the overall catalyst productivity increases (the diffusion and catalyst surface increases). The reaction gases leaving the reactor are condensed by cooling under pressure, and the carboxylic esters are liberated (ACIDS, above the total carbanoic acid and water). The condensate is processed in a known manner (by means of stripping). The residual reaction gas after adding the required amount olefins, carboxylic acid and, in the case of 1-pass; imosti, after the preliminary separation of the formed carbon dioxide, is again sent to the reactor.

The concentration of the unsaturated complex of the carboxylic acid complex in the raw condenser is 30-49 weight. % at productivity 900-1000 g of carboxylic acid ester per liter / hour of catalyst. It is especially valuable that the removal of the reaction heat at high production of catalyst in the fluidized bed is not laborious.

To maintain the activity of the catalyst, one or more alkali metal carboxylate compounds or other alkali metal compounds forming alkali metal carboxylates under the reaction conditions can be added to the gas mixture that passes over the catalyst, in an amount necessary to compensate for losses due to evaporation.

Aliphatic or cycloaliphatic olefins or diolefins, for example, ethylene, propylene, Nb, olefins, cycloaliphatic olefins or diolefins, ethylene, propylene, Nb, cbutane, butadiene, cyclopexane, cycloaliphatic olefins or 2 olefins with 2-10 carbon atoms can be used as initial olefinic compounds (with 2–20; . The starting carboxylic acids (c 2-20, predominantly with 3-10 carbon atoms and 1 atoms) can be, for example, acetic acid, propionic acid, butyric acid, valeric acid, lauric acid, palmitic acid, stearic acid or benzoic acid acid. Crawling unsaturated esters of carboxylic acids contain 4–40, mostly 4–20 carbon atoms.

For the preparation of Vipylacetate, it is possible to use instead of chemically pure acetic acid an acid that contains formic acid, such as formic acid L; reter: the catalyst does not quantitatively decompose into carbon dioxide and hydrogen, which instantly burns.

A small constituent part of the catalyst support may have a skull diameter outside the specified range of 0.1-0.5 mm. The process proceeds satisfactorily if, however, at least 80% (nanrnmer, 85 ° / o) of the under-catalyst: catalyst lies within these boundaries.

Example 1. A 3 liter of a silicic acid substrate with a particle size of 0.1-0.2 mm is progittered with a solution containing 30 g of shalladi acetate, 57 g of cadmium adatate, 60 g of potassium adatate and dried.

2.5 l of the catalyst obtained is placed in a fluidized bed reactor. The latter consists of a pipe heated by steam,

3 m long, made of steel 4A - and having an internal diameter of 50 mm. To reduce catalyst losses due to a damper, another tube with a diameter of 125 mm is placed on this pipe.

Through the catalyst placed in the pipe (2.5 l) at an initial pressure of 8 at and a temperature of 185 ° C, 10 nm per hour of gas with 65 vol. % ethylene, 16 vol. % acetic acid, 8 vol. % oxygen and 11 vol. ° / o CO2. The gas pressure is 4 H.W per liter of catalyst. Per hour, the residence time of the product in the apparatus is 4.2 seconds, IB is equivalent to the cross-section of the volume of the catalyst and the flow rate is 34 cm / sec.

Get in an hour 5700 g. Condensate with 44 weight. Vo vinyl acetate, 45 wt. % acetic acid and weight. % water. The yield of kata, lysator is 1000 g of vinyl acetate per liter of catalyst per hour. The conversion of acetic acid is 41%. The yield of vinyl acetate is 90.5Vo, in terms of 11% - the other conversion of ethylene.

Example 2. 3 liters of catalyst support from iremnic acid with a particle size of 0.1-0.2 mm. Prop. Solution containing 30 g of palladium acetate, 57 g of cadmium acetate and 70 g of potassium propionate and dried. 2.5 liters of the obtained catalyst are introduced into the fluidized bed reactor. The latter consists of a 3-mm-long stainless steel pipe heated by steam with an internal diameter of 50 mm. A tube with a diameter of 125 mm is placed on this reaction bed (in order to reduce catalyst losses).

Through (Placed in T1rubu catalyst (2.5 l). At INO. ONE pressure of 8 at and a temperature of 190 ° C, 10 nn gas per hour is passed with 65 vol. Vfi-ethyl, 16% by volume of 1 propioic acid , 7% by volume of oxygen and 12% by volume of CO2. The gas loading is 4 nm per liter of catalyst per hour, the residence time of an additional iB apparatus is 4.2 seconds in terms of the cross section of the catalyst volume and the flow rate is 34 .

The reaction products are removed from the reaction gas in the usual manner. Get 6400 g of condensate per hour with 35.4 weight. % vinylpropionate. The productivity of the catalyst is 905 g of vinyl propiopate on 1 l / h of catalyst. Vyho.d in terms of "and 8,6Vo-.Hoe ethylene conversion 91%. The degree of conversion of propionic acid is 31.6 / o.

E-meter 3. Under the conditions described in Example 2, isobutyl acid was introduced into the reaction instead of propanoic acid. The amount of the starting gas mixture in this test is also 4 nm per liter / hour of catalyst. The source gas contains 16 vol. % isobutyl | acid. Catalyst productivity 540 g of vinyl isobutyrate. The conversion of isobutyl acid is 16.5%, while the yield of vinyl isobutyrate is

In terms of 4.5 / o-Noah, the conversion of ethylene. The content of vinyl isobutyrate in raw condensate is 19.3 iBec. /about.

Example 4. Under the conditions described in Example 2, allyl acetate was prepared. The feed mixture in the amount of 4 nm per 1 l / hour of catalyst contains 61 vol. / about prapilena, 18 about. % xuonoy. acids, 7 vol. / o oxygen and 14 about: b. / o C02. Catalyst productivity 540 g of allyl acetate per 1 l / h of catalyst. At 5.8%: - the nominal conversion of propylene, the yield of allyl acetate is 85%. The by-product formation was 5% acrolein and about I ° / acrylic acid. The conversion of acetic acid to 16.8% with a content of 23.6 wt. Vo allyl acetate in raw condensate.

WITH)

Subject invention

Claims (2)

I. A method for producing unsaturated carboxylic acid esters by the gas-phase exchange decomposition of olefin-C2 and higher, carboxylic acid and oxygen at a temperature of 100-250 ° C and a pressure of 1-30 MPa in the packed catalyst layer containing palladium compounds, an activator and a carrier, with subsequent isolation of the target product, characterized in that, in order to simplify the process, a supported catalyst is used with a diameter of predominantly spherical parts of 0.1-0.5 mm. 2. A method according to claim 1, characterized in that silicic acid is used as a carrier.