SU957949A1 - Method of producing catalyst for olefin oligomerization - Google Patents

Description

with respect to 1: (2.0-3.0). The mass obtained after mixing the reagents matures for 20-24 hours at 20-25 ° C, then it is dried to a water content of 5-6 wt.% At 280-300 ° C. The dried mass is ground, moistened, molded into catalyst granules and calcined at 280-300 ° C.

The catalyst obtained by a known method, has a high initial strength (22, 4-49, 7 kg / tabl and stability of this strength, is active in the reaction of oligomerization of the propane-propylene fraction (conversion of propylene 73.0-79.0%), but has a reduced selectivity in relation to the conversion of proglen to propylene tetramers, equal to 10.0-18.0%. In addition, the known method is characterized by a complication of technology and an increase in the duration of catalyst preparation due to the inclusion of an additional stage of phosphooleum production, ost of the catalyst due to the use of scarce and costly phosphoric anhydride obtained catalyst has a low selectivity .prevrascheni propylene tetramers desired product.

The aim of the invention is to prepare a catalyst with increased selectivity.

To achieve this goal, a catalyst is prepared for the oligomerization of olefins by mixing pyrophosphoric acid with silica gel and a magnesium-containing component, in which magnesium oxide is used in an amount of 1.5-5.0 wt.%, Moistening, shaping and drying.

The proposed method, in comparison with the known, allows to obtain a catalyst with increased selectivity.

Thus, the catalyst obtained by the proposed method has a selectivity for the conversion of propylene to propylene tetramers, equal to 61-68%.

In addition, the proposed method makes it possible to exclude from the production technology of the catalyst the stage of the production of phospholeum and expensive phosphoric anhydride.

According to the invention, pyrophosphoric acid is mixed with silica gel and magnesium oxide and is chemically reacted. At the same time, the mass ratio of the main components - acid and silica gel is (2.5-3.0): and the amount of magnesium oxide - 1.5-5.0 wt.% To the total mixture. The mixture obtained is dried at 280-300 ° C, milled, scattered, moistened, molded into granules and dried at 280 ° C. Or, pyrophosphoric acid is mixed with silica gel in bulk

ratio (2.5-3.0): and their chemical interaction is carried out. The mixture obtained is dried at 280-300 ° C, milled, scattered and 1.5-5.0% of magnesium oxide is introduced into it, then

moisten, form into granules and dry them at 280-300 s.

An example. Pyrophosphoric acid containing 80% of phosphoric anhydride is mixed with silica gel.

0 and magnesium oxide at 170 ° C for 2.5 minutes. In this case, the mass ratio of acid to silica gel is 2.5: 1, and the amount of magnesium oxide is 5 May.% To the total mixture. The resulting loose mixture is kept at 20 ° C for 20 hours, dried at up to 5.6% by weight of water in the mixture, milled, scattered, moistened to 15.5% water content in the mixture,

molded into granules and dried at 280 ° C to a bound water content of 7.2% by weight in the catalyst. The finished catalyst contains wt.%: Pyrophosphoric acid 22.7; magnesium phosphate 1.08; silicophosphates rest, destroyed at a pressure of 29.0 kg / tab. Conversion of isobutylene while 84.1 wt.%. The selectivity for the yield of the target fraction 9O-130 ° C is equal to 61.0 wt.%.

0 Example 2. Pyrophosphoric acid containing 80% phosphoric anhydride is mixed with powdered silica gel at 180 ° C for 3 minutes with a mass ratio between them of 2.8: 1. The resulting crumbly mass is maintained at 20 ° C for 20 hours. It is then dried at 280 ° C until the water content

6.4% by weight, grind, dissipate and 0, 2.5% of magnesium oxide is introduced into it.

total mass. Next, the mixture is moistened, molded into granules and dried to a water content of 7.0% by weight. : The resulting catalyst contains 5% by weight: pyrophosphoric acid 21.9; magnesium phosphates 1.96; silicophosphate else, can withstand a load of 34.3 kg / tab. Conversion of isobutylene 85,0 May. %, selectivity 66, 5 wt.%.

Example 3. Pyrophosphoric acid containing 80% of phosphoric anhydride is mixed with silica gel and magnesia at 180 ° C for

3.5min. In this case, the mass ratio of acid to silica gel is 3.0: 1, and the amount of magnesium oxide to the total mass is 5.0% by weight. The resulting mass is further subjected to the operations indicated in Example 1. The finished catalyst contains, in wt.%: Pyrophosphoric acid 20.6; magnesium phosphates 1.96; silicophosphates the rest, is destroyed under the pressure of 49.4 kg / tab. Conversion of isobutine on this catalyst is 78.5 wt.%,

and the selectivity to the output of the fraction .90-130 ° C 52 wt.%.

Example 4 Pyrophosphoric acid containing 80% of phosphoric anhydride is mixed with silica gel and magnesium oxide for 3 minutes. The mass ratio of acid to silica gel is 2.8: 1, and the amount of magnesium oxide is 1.5% by weight of the total mixture. The resulting mixture was further subjected to the operations indicated in Example 1. The finished catalyst contained, in wt.%: Pyrophosphoric acid 21.9; magnesium phosphates 1.96; silicophosphates else, destroyed at a pressure of 32.0 kg / tab. Converse

isobutylene on this catalyst 83.0 wt.%. The selectivity for the yield of the target fraction 90-130 With 64.0 wt.%. Conditions for obtaining prototypes, their chemical composition and performance properties are given in Table. one.

The catalytic activity of the samples is determined in the reaction of oligomerization of isobutylene at atmospheric

pressure and 185 ° C. The degree of isobutylene conversion in wt.% Is taken as an indicator of the activity of the obtained catalysts, and the content in the polymer distillation of the fraction boiling in the range of 90-130 ° C is taken as an indicator of selectivity. I

Table I

From the data table. 1 it follows that in the studied range of ratios of magnesium oxide to the starting components, satisfactory readings are obtained both in selectivity and activity and in mechanical strength. The highest selectivity (in terms of polydistil distillation of the fraction boiling within 90130 ° C) and activity (in terms of the conversion of isobutylenes) is shown by test sample 5, obtained with a ratio of acid to silica gel of 3.0: 1 with the addition of 3.1% by weight of magnesium .

In addition, the magnitude of the positive effect of the addition of magnesium oxide to the catalyst is almost independent of what stage of the process it is introduced into (at the kneading stage or at the pre-molding stage).

Example 5 (comparative). Pyrophosphoric acid containing 80% of phosphoric anhydride is mixed with silica gel and talc at 180 ° C for 3.5 minutes. In this case, the mass ratio of the acid to silica gel is 3.0: 1, and the amount of talc in total mass is 5.0 wt.%. The resulting mixture is kept for 20 hours at 20 ° C, dried at 280 ° C until the moisture content in the mixture is 5.9% by weight, crushed, scattered, moistened, molded into granules and dried at 280 ° C until the water content in the catalyst 7, 1 wt.%.

The properties of the catalyst obtained in Example 5 are as follows. 2 in comparison with the properties of the catalyst obtained in the same well-. Viyah with the addition of MDO.

Content, wt.%: Pyrophosphate Acid Silicic Phosphates Magnesium Phosphates

Mechanical poemost, kg / tab.

Isobutylene converse,

wt%

Selectivity for the yield of fraction 90t130С,%

As follows from the table. 2, the catalyst with the addition of pure magnesium oxide has a selectivity of 8.7% more than in the case of talc. The catalyst also has enhanced activity and strength.

An experimental sample of the catalyst was accumulated on the actual prokkshshennom equipment for the production of a phosphorus catalyst and it was assigned the code number GSFO-E2. This catalyst sample was additionally tested for catalytic properties in the polymerization reaction of propylene in

23.2 75., 76 1.04

20.3 70.9 47.8

/ say x pilot installation. The tests were carried out at 180 ° C, pressure tS ati, flow rate for propylene 0.55 hours. The content of propylene in the feedstock is 45-50%. The average initial activity (total conversion of propylene) for the first 3 days of the catalyst is 88.0%, and the average initial selectivity is 3Q, 5%.

3§ The results of similar pilot tests for the catalyst obtained by known and proposed methods are given in Table. 3

Table 3

Claims (3)

Claim A method of preparing a catalyst for oligomerization of olefins by mixing pyrophosphoric acid with silica gel and a magnesium-containing component, moistening, molding and drying, characterized in that, in order to prepare a catalyst with increased selectivity, as a magnesium-containing component VNIIPI Order 6659/9 Tire conditions of a pilot plant . The tests are carried out at 180 ° C, a pressure of 75 MPa, a propylene space velocity of 0.55 h * ⁴ . The propylene content in the raw materials is 45-50%. The average initial activity (total propylene conversion) for the first 3 days of the catalyst was 88.0%, and the average initial selectivity 3Q, 5%. $ 3 The results of similar pilot tests for the catalyst obtained by known and proposed methods are shown in table. 3. Table 3 that uses magnesium oxide in an amount of 1.5-5.0 wt.%.