SU644766A1 - Method of obtaining olefins - Google Patents

Description

(54) METHOD OF OBTAINING OLEFINS

This invention relates to methods for producing olefins by catalytic disproportionation of unsaturated hydrocarbons, i.e., converting them into homologues with a higher or lower molecular weight by the following reaction:

The use of a catalyst that additionally contains molybdenum oxide allows the iCHH3HTb content of rhenium oxide in the catalyst to be 0,, 0 wt. % without changing its activity.

The rate of disproportionation reaction on an aluminum-molybdenum catalyst (HeO + MOOO / AO 3) containing 0.5-1.0 wt. % RezO, 5th weight. % MOOS and weight. 5% Sn (C4H9) 4 is equal to 4170-5600 ml of olefinyl cathe hour. Reducing the content of Re2O7 below 0.5 wt. % results in a less active catalyst, and an increase above 1 weight. % is advisable due to the increase in the cost of the catalyst.

The disproportionation of olefins is carried out on an alumina-molybdenum catalyst modified by tetraalkyl derivatives of tin. The catalyst is prepared by impregnating the y-alumina industrial with ammonium perrhenate and ammonium molybdate at an appropriate ratio. After the substance and calcination, the catalyst was applied tetraalkyl tin derivative. The catalyst thus obtained is charged in an inert gas to the reactor. The reaction is carried out at a temperature of about -60 ° C and

 Prototype data. Additive 5 wt. % Sn (C2H5) 4.

As can be seen from the table. 1, on the catalyst Re2O7 + MoOZ / A Oz + Sn (C4P9) 4, containing 0.5-1.0 wt. % Re2O7 and 5-10 wt. % MoOS, the disproportionation rate of n-heptane-1 is higher than at Re207 / Al203-KaTalizer modified by tetrabutylatmospheric pressure in a static or flow system.

Example 1. Disproportionation / g-heptene-1 is carried out in a static system in the liquid phase with mixing and continuous removal of one of the reaction products, ethylene, at 30 ° C. N-hepten-1 is the raw material. Analysis of the reaction products is carried out by chromatographic method. Product identification is carried out by means of IR, NMR and mass spectrometry. The catalyst was prepared by impregnating industrial (surface 200) ammonium lerrenate and ammonium molybdate. The compositions of the catalysts are given in table. 1. Alumina is preliminarily calcined in a stream of air at 450 ° C for 2 h, and then purged with nitrogen for 1 h at the same temperature. After impregnation with solutions of salts of rhenium and molybdenum and catalyst, the catalyst is treated at 580 ° C with air (I h) and nitrogen (1 h). Sn (C4H9) 4 was deposited on the catalyst thus prepared from a solution in pentane. The amount of solution should be taken at the rate of 5 wt. % Sn (C4H9) 4 in the catalyst. The pentane is then removed by flushing with nitrogen. The results are shown in Table. 1. The reaction rate is assessed by the amount of evolved gas.

T a b l 11 c a 1

ml cat hour

4110 36

BY:

5600

57CG

4720

4170

1280

by fishing It should be noted that the replacement of tetrabutyl tin with tetraethyl tin does not change the reaction rate. The process selectivity is 90%. The composition of the reaction products indicates the disproportionation of n-heptene-1 by the reaction: (CH2) 4-CHj The reaction products are dodecene-6 and ethylene. Example 2. The disproportionation of n-heptene-1 is carried out in a static system in the liquid phase with mixing and continuous removal of one of the reaction products, ethylene, at 0 ° C and 60 ° C per kata. Prototype data.

From tab. 2, it can be seen that, at the indicated temperatures, the promotion of the aluminum catalyst with molybdenum oxides also leads to an increase in its activity. The composition of the disproportionation reaction products corresponds to the course of reaction (2). Selectivity of 90%.

Example 3. Disproportionation

 Prototype data.

From tab. 3, it can be seen that on an alumina-molybdenum catalyst modified with tetrabutyl tin, the disproportionation rate is equal to the reaction rate on an alumina catalyst, although the rhenium content is 40 times less.

According to chromatographic and mass spectrometric analyzes, the products

propylene is carried out in a flow-type installation at 20 ° C on a catalyst Re2O7 + Lmooz / AoOz (composition, wt.%; 0.5 Re2O7, 10 MoOz, 89.5 Ahoz) modified with 5 wt. % Sn (C4H9) 4. The conditions for preparing the catalyst are similar to those described in Example 1. The results are shown in Table. 3

Table 3

reactions are ethylene and a mixture of butenes-2. The ratio of gran-butene-2/1 {HC-butene-2 is 6: 1. Butene-1 is absent in the reaction products.

Claims (2)

The invention The method of producing olefins by bottom. Br- (cn,), cn, CH-CCH 1 -CH j lysator Ke207 + MOOS / A12Oz (composition, wt.%: 0.5 RegO. JuMoZ, 89.5 AlaOs) with addition of 5 wt. % Sn (C4H9) 4. The conditions for the preparation of the catalyst are similar to those described in Example 1. The composition of the catalysts and the results obtained are shown in Table. 2. Table 2 the proportion of olefins in the presence of an oxide alumina catalyst modified with tetraalkyl tin, characterized in that, in order to reduce the cost of the process, a catalyst is used that additionally contains 5-10 wt. % molybdenum oxide with a rhenium oxide content of 0.5-1 wt. % 2. A method according to claim 1, characterized in that the process is carried out at O-60 ° C. Sources of information taken into account in the examination: 1. The patent of England No. 1054864, cl. C 5 E, 1967. 2. Authors certificate of the USSR L 517575, cl. C 07 C 3/62, 1976 (prototype).