SU455082A1 - The method of obtaining -butylene - Google Patents

Description

The invention relates to the field of producing a-butylene by dimerizing ethylene.

A known method of producing a-butylene by dimerizing ethylene in the presence of a catalytic Ti (OR) 4-Al (C2I5) s system in a hydrocarbon solvent.

The disadvantages of this method include the low catalyst activity and the selectivity of the process for a-butylene, as well as the low yield of the target product.

To eliminate these drawbacks, it is suggested that the dimerization of ethylene be carried out in the presence of a catalytic system containing an additive of isopropyl ether or dioxane.

The dimerization process is carried out in an autoclave at a constant pressure and continuous supply of ethylene. Process conditions: temperature 20-100, preferably 40-70 ° C, pressure 1-20, preferably 1-5 atm. The inert solvent is selected from hydrocarbons: hexane, heptane, cyclohexane, baseol, toluene, or mixtures thereof. The molar ratio of tetra1-alkoxytitanium to triethylaluminum is from 1: 1 to 1: 8, preferably from 1: 3 to 1: 5, and the molar ratio of tetraalkoxytitanium to the modifying additive is from 1: 0.01 to 1: 1.5, preferably from 1: 0.02 to 1: 1; the concentration of Ti (OR) 4 is 0.4-3.0, preferably 0.6-2.0 g / l. The catalyst complex is prepared from solutions of AlRa and Ti (OR) 4 in heptane with a concentration of 40 g / l at a temperature of 20-50, preferably 20-30 ° C, and a shutter speed of 5-60, and preferably 15-30 minutes, and then brought to working The center of Ti (OR) 4 is diluted with a solvent having t. 74-94 ° C. The modifying additive of diisopropyl ether or dioxane is introduced into the catalyst of Comilex together with the solvent, which is desirably diluted.

The essence of the method is illustrated by the following irimera.

EXAMPLE 1. A metal autoclave with a capacity of 2 liters is loaded with an educer prepared (preparation temperature 25 ° C, holding time 15 min. Catalyst mixture consisting of 1.25 g Ti (OC4H9) 4, 1.9 g A (C2H5) s and 0.075 g (CzH7) 2O. The molar ratio of Ti (OC4I9): Al (C2H5) is 4.5: 1, the molar ratio of Ti (OC4H9) 4:: (CzH7) 2O 1: 0.2 The components of the catalytic system did not contain irimeses.

Zatom.m load 0.5 liters of hexapic fraction and serves ethylene. The ethylene feed rate varies from 160 g / h at the initial moment to 45-50 g / h at the end of dimerization. The process temperature is 70 ° C, the pressure is 2.5 MPa. Duration d, imeriazni 1.5 hours. The dimerization rate is 91 g / h a C4ns / Ti (OC4I9) 4. The composition of fraction C,%:

n-butane0.4

a-butylene 99.3

p-butylene0,3

Example 2. Same as in example 1, only the pressure of 7.5 MPa. The ethylene feed rate ranges from 350 to 107 g / h at the end of the dimerase. The velocity of the measure

224.5 g / hr a CJig / Ti (OC4Bj) 4.

Composition

n-butane 0.52

a-butplen 99.3

p-butylene 0,18

Example 3. Same as in example 1, only pressure 15 agi. The ethylene feed rate varies from 620 to 180 g / h. The rate of dimerizac is 370 g / h and C4H8: Ti (OC4H9) 4.

The composition of the fraction

n-buta 0.38

a-butylene 99,42

p-bootlen0,1

Example 4. A pre-cooked metal autoclave with a capacity of 2 l (prepared at 25 ° C, holding time 15 min) is loaded with a catalpator complex consisting of 0.375 g 100% Ti (OC4H9) 4, 0.5 g 100% A1 (C2H5 ) C and 0,018 g dpizoproplivogo ether.

Then, 0.5 l of the hexane fraction I is charged, and ethylene is continuously fed for 40 minutes and ethylene is fed under constant pressure in the reactor. The dimerization temperature is 80 ° C, the pressure is 4 MPa. Absorption of ethylene 71.5 g. Dimerizate yield 190 g / g Ti (OC4H9) 4. No polymer available. The amount of hexane from dimerizat 5.2% wt. The composition of the C4 fraction, vol.%:

n-butai0,3

a-butylene 99.25

p-butylene (trans) 0.45

: p-butylene (cis) is absent.

Example 5. Same as in example 4, only the composition of the catalyst Ti (OC 4 H 9) 4:: 4.5 A1 (C 2 P 5) g: 0.5 dioxane. Concentration T1 (OC4H9) 4 0.5 g / l. Heptane solvent. Dimerizacin time 1 hour. The process pressure is 2.8 ati. The ethylene absorption rate is 222.7 g / g Ti (OC4H9) 4. The yield of by-products does not exceed 10% of the absorbed ethylene.

Subject invention

The method of obtaining α-butyl-dimers of ethylene on the catalytic system of tetraalkoxytitanate-trialkylaluminums in a hydrocarbon solvent medium, characterized in that, in order to increase the yield of the final product and selectivity of the process, a catalytic system containing an additive of dppzopropyl ether dioxane is used.