SU1011624A1 - Process for purifying isobutylene from carbonyl compounds - Google Patents

Description

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41 The invention relates to the production of monomers for synthetic uchuky, in particular isobutylene, used in the production of butyl rubber. In the process of cationic copolymerization of isobutylene with isoprene, the stability of the monomer in composition and content of trace impurities, in particular carbonyl compounds, is of great importance for improving the quality of the products and the productivity of equipment. The negative effect of the microprime of carbonyl compounds lies in the fact that these compounds in the implementation of the polymerization act as catalytic poisons. As a result, the conversion of monomers is reduced, the consumption of an expensive catalyst increases, the molecular weight of the copolymerization product decreases. Therefore, the content of carbonyl compounds in isobutylene, used for the synthesis of butyl rubber, should not exceed 2,.%. A known method of purification of olefinic hydrocarbons from carbonyl compounds by extraction with water. The disadvantage of this method is the need for subsequent deep drying of the monomer, which complicates the process. In addition, the depth of cleaning is insufficient. Closest to the invention is a method for the purification of isobutylene from carbonyl compounds by adsorption of anion exchange resins on a solid sorbent. The process of purification of isobutylene is carried out using, for example, anion exchange resins of the following brands: AB-17; LN-ZG and AN-2FN with functional groups HCCW-j) HN -. Isobutylene containing carbonyl compounds is fed to the purification at a rate of 200-300 hours in the gas phase at TV-SO3. A disadvantage of the known method is its complexity associated with the need for frequent replacement of the adsorbent-anion-exchange resins, which quickly lose their adsorption properties In addition, the cleaning process has a low productivity, since it is carried out at relatively low volumetric feed rates (200-300 hours), due to the properties of anion-exchange resins. The aim of the invention is to increase the productivity of the isobutylene purification process and simplify it. This goal is achieved according to the method of purification of isobutylene from carbonyl compounds by adsorption on a solid sorbent of a type MDA zeolite at 18-ZO С with a volume feed rate of isobutylene 600800 hr. Zeolite MDL retains the original adsorption properties after multiple regenerations, which avoids frequent replacement of the spent adsorbent due to its repeated use. In addition, the proposed method allows the process to be carried out at high speeds, which significantly improves its performance compared to the known. The method of purifying isobutylene from carbonyl compounds using a zeolite of the type MDA can be used to purify highly concentrated isobutylene, obtained as a by-product in isoprene production plants through dimethyldioxane, with the aim of improving its quality and its further use for the synthesis of butyl rubber. Example. Isobutylene containing (O, 1–3.9) .1 carbonyl compounds is fed for purification to the top of the adsorber with an internal diameter of 6 mm. A 50 cm of air-dry zeolite MDA with a height of 38.5 cm is preloaded into the adsorber. Heochil; Ene isobutylene is passed in the gas phase through the adsorbent bed at a speed of 600-800 LT for l8-30c for 4-5 hours. Purified isobutylene coming from the bottom of the adsorber is analyzed for carbonyl content. At the end of the purification cycle, a sample of the adsorbent — Zeolite MDA — is regenerated in order to burn carbonyl compounds, for which they are passed through; air at a rate of 25-35 l / h at 50-480 6 for 3-4 h. At the end of the regeneration, the zeol-g is cooled to the purification temperature in

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current of dried and purified azo-results of experiments with different if honest regenerations, different degrees of

On the regenerated zeolite, the initial isobutylene is contaminated and the cleaning cycle is repeated again with the following different conditions of the process portions of the crude isobutylene a. $ cleaning parameters are summarized in the table.

Conditions for the implementation of the isobutylene purification stage Temperature, C

Volume szhorozhnost feeds isobutyl on (calculated on gas), h Duration of experience, h

The content of carbonyl compounds in isobutylene, May L 10

before cleaning after cleaning

The amount of oxidative regenerations to which zeolite was subjected

Regeneration Conditions

Temperature, C

Air flow rate, l / h

Duration, hour

With the help of zeolite MDA deep purification of isobutylene from carbonyl compounds is achieved.

In addition, after a number of cycles (purification - regeneration), the zeolite does not

25 30 30 25 18

20

600 600 600 600 800 800 5.0 5.0 5.0 5.0 k, 0 k.Q

3.5 3.9 2.A 2.5 1.8 0.1 O, 0.7 0.1 O, L 0.3 OST.

ten

20

kSO 480

25 30 35 35 25 30 4,0 4,0 3,5 3,5 3,5,0,0,0,0

loses the ability to adsorb undesirable impurities of carbonyl compounds, so it can be reused in the process of purifying isobutylene from carbonyl compounds.

Claims (1)

METHOD OF CLEANING ISOBUTENEN FROM CARBONYLIC COMPOUNDS by adsorption on a solid sorbent at 18-30 ° С, characterized in that, in order to increase productivity and simplify the process, an MDA type zeolite is used as a solid sorbent, and the process is carried out with a volumetric feed rate of 600- 800 h - ⁴ . SU _m 1 () 11624> 101 1624