SU968023A1 - Process for producing isobutylene - Google Patents

Description

(54) METHOD FOR PRODUCING ISOBUTYLENE

Claims (2)

This invention relates to a process for the preparation of eobutylene by depolymerizing its polymers. There are known methods for the thermocatalytic destruction of di-and trimers of isobutylene to obtain pure isobutene at 200-400 ° C, a pressure of 17 atm in the presence of mineral catalysts of natural clay, silica gel or phosphoric acid on diatomaceous earth. Isobutylene is obtained in 80-85% U yield. The disadvantage of this method is the insufficiently high yield of isobutylene and intensive coke formation, which requires constant catalyst regeneration. The closest in technical essence to the present invention is a method for producing isobutylene by depolymerizing oligomers and polymers of isobutylene at a temperature of 200400 ° C in the presence of a catalyst of the complex salt Me RAiralj, where R is methyl, ethyl; Not - To, Na, Li; G1 - Cl, Br, polyisobutylenease conversion of 60-120 m reaches 85% 2. The disadvantage of this method is not high enough, the speed of the process, the high sensitivity of the catalyst to moisture and air oxygen. The aim of the invention is to increase the speed of the process and simplify its technology. This goal is achieved by the fact that according to the method of producing isobutylene by depolymerization of oligomers and polymers isobutylene at a temperature of 200-400s in the presence of a catalyst, the complex salt of the general formula MMEG, where M is Na, L i, K; Me - Al, Ga,. Tl; Ha I -Cl, g, I, -, in the amount of 210 -6-10 mol / g polymer. In addition, a catalyst supported on a mineral carrier is used with a catalyst: carrier ratio of 3: 2-5. The proposed method allows not less than half the contact time to achieve a conversion close to 100%. The catalyst is obtained by simple fusion of the salts of MGa.1 and MeGa. The application of a catalyst to substrates improves its technological properties, and also provides its additional homogenization, prevents the formation of large aggregates. Example 1. The test is carried out in a 20 cm glass reactor equipped with a reflux condenser and a product gas collector cooled with an acetone / carbon dioxide mixture. The reactor is charged with 2 g of polymer (molecular weight 640) and introduced into the catalyst. The catalyst is prepared by sintering the molar ratios of the alkali metal halide with the corresponding metal halide of the W group in an inert atmosphere. The catalysts applied to the mineral substrates are obtained by sintering the corresponding components in the presence of a previously calcined and evacuated carrier with vigorous stirring. The resulting catalyst, NaAlCl4, in a quantity of 4–10 mol / g of polymer is loaded into a reactor, which is immersed in a bath at. After 30 min, 2.2 ml of isobutylene was obtained, the degree of purity was 96.7%, the conversion was 62.5%. After 60 min - 3.1 ml of isobutylene, conversion - 100%. Example 2. The experiment was carried out analogously to example 1, with the difference that the catalyst NaAlCl4 was introduced into the reactor. applied on sterhomol, temperature 400 ° C, in an amount of 4-103 mol / g of polymer, molecular weight 960. After 30 min of reaction for different catalyst / carrier ratios isobutylene was obtained: Pure nosi, 1% (1.4 ml) body 59 , 0% (2.0 ml) 63% (2.1 ml) 70% (2.3 ml) 95.3% (3.2 ml) After 60 min, convert for all cases except the first 100%. The degree of purity of isobutylene - 94.2%. Example 3. The experiment was carried out according to the procedure described in the example. The catalyst deposited on zeolites NaX, pre-milled and sifted into fractions 0.5-0.25; 10, 5 mm, is introduced into the reactor at a concentration of 2-10 mol / g polyisobutylene, molecular weight 640. At a temperature of 350 ° C in 30 minutes for different catalyst / carrier ratios and different degrees of granulation, isobutylene is obtained: Fraction - 0.5- 0.25 mm 3/5 - 73.0% (2.4 ml) 3/4 - 89.1% (3.0 ml) 3/3 - 94.2% (3.2 ml) 3/2 - 100% (3.3 ml) Zeolite - 64.0% (2.1 ml) Fraction - 1 - 0.5 mm 3/5 - 70.1% (2.3 ml) 3/4 - 84.0% (2.8 ml) 3/3 - 92.1% (3.1 ml) 3/2 - 100% (C, 25 ml) Zeolite - 60% (2.0 ml) After, 60 min. Convert in all cases x 100%. The degree of purity of isobutylene is 97.0-98.2%. Example 4. The experiment was carried out analogously to example 1. A carrier-zeolite brand NaA. The degree of granulation is 0.5-025 mm, 1-0.5 mm, NaA 1C 14 2.10 mol / g polymer, molecular weight 1000. After 30 minutes, isobutylene was obtained at a temperature of 320 ° C: Fraction - 0.5-25 ml Zeolite - 41.0% (1.3 ml) 3/5 - 59.2%. (2.0 ml) 3 / 4.- 61.1% (2.05 ml) 3 / 3.- 65, 3% (2.2 ml) 3/2 - 95.0% (3.2 ml) Fraction -1 - O, 5 mm Zeolite -40.3% (1.25 ml). 3/5 -50.5% (1.7 ml) 3/4 -60.0% (2.0 ml) 3/3 -7.1% (2.3 ml) 3/2 - 100% (3 , 3 ml.). . After 60 minutes, the conversion in all ray x is 100%. The degree of purity of gobutylene is 94.1-96.2%. And p. and measure 5. The experiment is carried out analogously to example 1. NaAlCl4 2.7-10 mol / g: polymer, catalyst / carrier 1/1. Temperature 370 ° C, molecular weight 860. NaX zeolite. To determine the possibility of repeated use of the catalyst, a new portion of the polymer is introduced into the flask every 30 minutes (2 g. 5. Isobutylene is obtained: 96.2% (3.25 ml), 94.3% (3.17 ml), 98.1% (3 , 25 ml), 95.7% (3.2 ml), 96.8% (3.2 ml), 93.2% (3.1 ml), 97.4% (3.3 ml), 96.1 % (3.2 ml), 95.3% (3.2 MP), 96.2% (3.1 ml), 97.0% (3.2 ml), 91.6% (3.0 ml , 95.4% (3.2 ml), 97.7% (H.,). No gumming was observed. The isobutylene purity was 97.3%. Example 6. The experiment was carried out as in Example 1 with the difference that LiGaF compounds are used. NaGaG, LiGaBr, KGaBr -, KGa 1 in individual form. The concentration of the catalyst is 410 mol / g polymer, molecular weight 1200. After 30 min, a temperature of 350 ° C of isobutylene was obtained with an output of wt.%: 98.0 (3.25 ml), 96.7 (3.2 ml), 95.2 (3 , 2 ml), 94.1 (3.1 m 95.6 (3.2 ml) for each system, respectively. When used as a carrier, an NaX brand zeolite with a catalyst / zeolite ratio is 1/1 with firm equal conditions, isobutylene obtained: 98.7% (3.25 ml), 98.0% (3,), 97.1% (3.1 ml), 96.2% (3.2 ml), 97.9% ( 3.2 ml), respectively. The degree of purity of isobutylene is “92.3-96.2%. Example 7. The experiment was carried out analogously to Example 1. The compound ЫALTC was used as a catalyst in concentration b, 3 10 mol / g of isobutylene polymer, molecular weight 980. After 30 minutes at 350 ° C, 98.6% (3.0 ml) of isobutylene was obtained. The degree of the number of 86.4%. PRI and MER 8. Using the procedure of Test 1, polymer (molecular weight 2700) was introduced as a catalyst (2.7-10 mol / g of the polymer of the CLCP compound and Na3nCl4. After 30 min at 350 ° C, isobutylene was obtained 84.3% (2.8 ml) and 85.7% (2.6 ml), respectively. The degree of purity is 91.0 93.0%, Example 9. The experiment was carried out according to Example 1 with the difference that NaAlCljBr, MaA1Br4, NaAlBr Cl, KAlBr Cl were used as a catalyst. The catalyst (molecular weight 1700) at 225 ° C was injected in an amount of 3.1 ČSH mol / g of polymer. 1.8 ml), 59.1% (2.0 ml), 51, (1, b ml), 56.2% (1.8 ml), respectively, and after 60 min - 87.2% (2.9 ml), 84.1% (2.8 ml), 87.7% (3, 0 ml), 80.0% (2.6 mp) Monomer purity 84-92%. Claim 1, Method for producing isobutylen by depolymerization of oligomers and polymers of isobutylene at a temperature of 200-400 ° C in the presence of a catalyst, salt based on metal halides I and III groups, characterized in that, in order to increase the speed and simplify the process technology, as a complex salt based on the halgenides of metals I and III groups, a compound of the general formula MMeGa14 is used, where M - Li, Na, K; Me - A1, Ga, In.Tl; HA I - C1.Vg, I, in the amount of 2-10 -6-10 mol / g polymer. 2. Method POP.1, characterized in that a catalyst supported on a mineral carrier is used at a weight ratio of carrier catalyst 3: 2-5. Sources of information taken into account during the examination 1. G. G., Polyisobutylene, L., 1962, p. 83 2. Authors certificate of the USSR according to the application 2508241/05, class C. 07 C 3/36, 1977 (prototype).