Search

CN-122010672-A - Toluene and method for recovering toluene from toluene-containing organic solution and application thereof

CN122010672ACN 122010672 ACN122010672 ACN 122010672ACN-122010672-A

Abstract

The invention relates to the field of material purification, in particular to toluene, a method for recovering toluene from toluene-containing organic solution and application thereof. The method comprises the steps of carrying out first-stage refining and second-stage refining on an organic solution subjected to water washing, dehydration and distillation, wherein the first-stage refining is carried out in the presence of a 4A molecular sieve, and the second-stage refining is carried out in the presence of a 5A molecular sieve. According to the method, the toluene-containing organic solution subjected to pretreatment under different conditions is treated, so that the content of impurities such as alkane in toluene can be obviously reduced, and the recycling frequency of the obtained toluene is obviously increased.

Inventors

  • HU HAIQIANG
  • LI KEZHI
  • ZHAO BAOHUAI
  • HAN SHUAI
  • REN JING
  • LIU YUJIAO

Assignees

  • 中国石油化工股份有限公司
  • 中国石化催化剂有限公司

Dates

Publication Date
20260512
Application Date
20241112

Claims (10)

  1. 1. A method for recovering toluene from a toluene-containing organic solution, characterized in that the method comprises subjecting an organic solution subjected to water washing, dehydration and distillation to a first-stage purification and a second-stage purification; The first stage refining is performed in the presence of a 4A molecular sieve and the second stage refining is performed in the presence of a 5A molecular sieve.
  2. 2. The method of claim 1, wherein the first stage refining is performed in the presence of a mixture of 4A, 5A molecular sieves and at least one of modified ZSM-5 molecular sieves, CHA molecular sieves, ZSM-11 molecular sieves, ZSM-35 molecular sieves, Preferably, the mixture has a 4A molecular sieve content of 10 to 35 wt% and the mixture has a 5A molecular sieve content of 20 to 55 wt%.
  3. 3. The method of claim 1 or 2, wherein the second stage refining is performed in the presence of a mixture of a 5A molecular sieve and at least one of a modified ZSM-5 molecular sieve, CHA molecular sieve, ZSM-11 molecular sieve, ZSM-35 molecular sieve, Preferably, the 5A molecular sieve is present in the mixture in an amount of 10 to 25 wt.%.
  4. 4. A process according to any one of claims 1 to 3, wherein the conditions of the first stage refining comprise a refining temperature of 15 to 40 ℃ and a refining time of 15 to 25 hours.
  5. 5. The process of any one of claims 1-4, wherein the conditions of the second stage refining comprise a refining temperature of 25-50 ℃ and a refining time of 10-20 hours.
  6. 6. The method of any of claims 1-5, wherein the temperature of the second stage refining is 10-25 ℃ higher than the temperature of the first stage refining.
  7. 7. The process of any of claims 1-6, wherein the toluene-containing organic solution is an organic solution produced during the preparation of a polyolefin catalyst.
  8. 8. The process of any of claims 1-7, wherein the organic solution contains 1-5 wt.% hexane, 94-98 wt.% toluene, 0.5-1 wt.% titaniferous material, 0.5-1 wt.% other alkanes, and 0.01-0.5 wt.% water.
  9. 9. Toluene recovered by the process according to any one of claims 1 to 8, characterized in that the toluene content is greater than or equal to 99.80 wt% and the total alkane content is less than or equal to 0.20 wt%; Preferably, the water content in the toluene is less than or equal to 15 mug/g.
  10. 10. Use of toluene according to claim 9 in the preparation of polyolefin catalysts.

Description

Toluene and method for recovering toluene from toluene-containing organic solution and application thereof Technical Field The invention relates to the field of material purification, in particular to toluene, a method for recovering toluene from toluene-containing organic solution and application thereof. Background Since the advent of Ziegler-Natta catalysts in the 50 s of the 20 th century, the comprehensive properties, appearance morphology, preparation methods and the like of the catalysts have been continuously improved, and the vigorous development of the polyolefin industry has been promoted. Although the metallocene catalyst and the late transition metal catalyst which are developed later are paid attention to, the Ziegler-Natta catalyst is still dominant in the polyolefin field at present and in the future, wherein the granular polyolefin catalyst is taken as a typical Z-N catalyst, the preparation process generally needs to use toluene to dissolve magnesium chloride, and then the processes of ester treatment, toluene titanium tetrachloride treatment, hexane washing, catalyst pumping and the like are carried out, but the toluene input amount in the preparation process is far greater than the toluene consumption amount in the catalyst preparation process, so that the continuous increase of the organic solvent amount is caused, the long-period operation of a device is influenced, toluene is taken as an important organic solvent, the purity of the catalyst can have a great influence on the quality of the synthesized catalyst, and therefore, the purity of the catalyst needs to be required in the use process of toluene, and the organic solvent needs to be purified and recycled. CN111111248a proposes a method of removing impurities such as titanium-containing substances and hexane in an organic solvent by means of water washing, distillation, rectification, etc., to obtain toluene with toluene purity of 99.5% and recycling the toluene to the catalyst preparation process, but along with the production operation of the apparatus, it is found that the organic solvent also contains a small amount of impurities such as straight chain and branched paraffins such as hexane, ethylpentane, 3-methylheptane, etc., and the concentration of the organic solvent gradually increases along with the increase of the operation time, and the quality of the catalyst product is affected. Disclosure of Invention The invention aims to solve the problems of incomplete purification and difficult reuse of toluene solution in the prior art, and provides toluene, a method for recovering toluene from toluene-containing organic solution and application thereof. The method can lead the content of the obtained toluene impurities such as alkane not to exceed 0.2 weight percent, and greatly increase the recycling times of the toluene. In order to achieve the above object, the first aspect of the present invention provides a method for recovering toluene from an organic solution containing toluene, comprising subjecting the organic solution subjected to water washing, dehydration and distillation to a first-stage purification and a second-stage purification, wherein the first-stage purification is carried out in the presence of a 4A molecular sieve and the second-stage purification is carried out in the presence of a 5A molecular sieve. According to a second aspect of the present invention, there is provided toluene recovered by the process of the first aspect, wherein the toluene content is not less than 99.80% by weight and the total alkane content is not more than 0.20% by weight. In a third aspect, the invention provides the use of toluene according to the second aspect in the preparation of a polyolefin catalyst. Through the technical scheme, the invention has the following advantages: According to the method, the toluene-containing organic solution subjected to pretreatment under different conditions is treated, so that the content of impurities such as alkane in toluene can be obviously reduced, and the recycling times of the obtained toluene are increased. Drawings FIG. 1 is an apparatus and flow diagram for recovering toluene from toluene-containing organic solutions in accordance with a preferred embodiment of the present invention. Description of the reference numerals 1. The device comprises a storage tank, a first water washing tank, a layering tank, a waste water collecting tank, a second water washing tank, a distillation tower, a toluene recovery tank, a distillate recovery tank, a toluene primary refining tower, a toluene secondary refining tower, a toluene recovery tank, a distilled matter recovery tank, a toluene primary refining tower, a toluene secondary refining tower and a toluene recovery tank. Detailed Description The endpoints and any values of the ranges disclosed herein are not limited to the precise range or value, and are understood to encompass values approaching those ranges or values. For numerical ranges,