CN114989047A - Method for recovering dimethyl sulfoxide from waste organic solvent - Google Patents
Method for recovering dimethyl sulfoxide from waste organic solvent Download PDFInfo
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- CN114989047A CN114989047A CN202210862850.7A CN202210862850A CN114989047A CN 114989047 A CN114989047 A CN 114989047A CN 202210862850 A CN202210862850 A CN 202210862850A CN 114989047 A CN114989047 A CN 114989047A
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C315/00—Preparation of sulfones; Preparation of sulfoxides
- C07C315/06—Separation; Purification; Stabilisation; Use of additives
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C41/00—Preparation of ethers; Preparation of compounds having groups, groups or groups
- C07C41/01—Preparation of ethers
- C07C41/34—Separation; Purification; Stabilisation; Use of additives
- C07C41/40—Separation; Purification; Stabilisation; Use of additives by change of physical state, e.g. by crystallisation
- C07C41/42—Separation; Purification; Stabilisation; Use of additives by change of physical state, e.g. by crystallisation by distillation
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C67/00—Preparation of carboxylic acid esters
- C07C67/48—Separation; Purification; Stabilisation; Use of additives
- C07C67/52—Separation; Purification; Stabilisation; Use of additives by change in the physical state, e.g. crystallisation
- C07C67/54—Separation; Purification; Stabilisation; Use of additives by change in the physical state, e.g. crystallisation by distillation
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Abstract
The invention provides a method for recovering dimethyl sulfoxide from a waste organic solvent, wherein the waste organic solvent comprises dimethyl sulfoxide, propylene glycol monomethyl ether and propylene glycol methyl ether acetate, and the method comprises the following steps: carrying out first vacuum rectification treatment on the waste organic solvent, and recovering to obtain propylene glycol monomethyl ether; carrying out second vacuum rectification to remove residual propylene glycol monomethyl ether; carrying out third vacuum rectification and separating to obtain propylene glycol monomethyl ether acetate; performing fourth vacuum rectification to remove residual propylene glycol methyl ether acetate; and carrying out fifth vacuum rectification, and recovering to obtain the dimethyl sulfoxide. According to the invention, by controlling the conditions in the rectification process, the separation of dimethyl sulfoxide, propylene glycol monomethyl ether and propylene glycol methyl ether acetate can be realized, the economic benefit of separating and recovering dimethyl sulfoxide is further improved, and the method has extremely high industrial application value.
Description
Technical Field
The invention belongs to the technical field of environmental protection, relates to a waste liquid treatment method, and particularly relates to a method for recovering dimethyl sulfoxide from a waste organic solvent.
Background
Dimethyl sulfoxide (DMSO) is a sulfur-containing compound with the molecular formula of (CH) 3 ) 2 SO，It is colorless and odorless transparent liquid at normal temperature, and is easily soluble in water, alcohol, ether and ester, and has strong hygroscopicity. DMSO is an aprotic polar solvent, is called as a universal solvent because DMSO has special solvent effect on chemical reaction and dissolution property on a plurality of substances, and has wide application in a plurality of chemical fields such as petroleum, chemical industry, medicine, electronics, synthetic fibers, plastics, printing and dyeing and the like.
For example, CN104817481A discloses a process for recovering DMSO from a DMSO aqueous solution, which comprises treating with a first-stage dehydration tower, a second-stage dehydration tower, a third-stage dehydration tower, and a product tower, rectifying the product tower, condensing from the tower top to obtain a DMSO product, feeding the material in the product tower into a scraper evaporator and an evaporator to evaporate the residual DMSO, so as to increase the yield of DMSO; and the first-stage dehydration tower, the second-stage dehydration tower, the third-stage dehydration tower and the product tower first-stage recovery evaporation system are operated by adopting a negative pressure process.
CN104119256A discloses a method and a device for purifying dimethyl sulfoxide, which comprises: feeding the raw material containing dimethyl sulfoxide into a first evaporator for heating, carrying out gas-liquid separation after partial evaporation, and feeding the obtained gas phase into a rectifying tower; inputting the obtained liquid phase into a second evaporator for heating, carrying out gas-liquid separation after partial evaporation, inputting the obtained gas phase into a distillation tower, and inputting the obtained liquid phase into a wiped film evaporator; collecting a dimethyl sulfoxide crude product at the bottom of the rectifying tower, inputting the dimethyl sulfoxide crude product into a third evaporator for heating, carrying out gas-liquid separation after partial evaporation, inputting the obtained liquid phase into a wiped film evaporator, and returning the obtained gas phase to the rectifying tower as a feed; and heating and partially evaporating the third evaporator, feeding back a gas phase obtained by gas-liquid separation to the first evaporator as a heating medium, and condensing to obtain purified dimethyl sulfoxide.
CN102225904A discloses a recovery and refining device and a separation method for dimethyl sulfoxide, which comprises a first-stage dehydration tower, a wiped film evaporator, a primary distillation intermediate tank, a second-stage dehydration tower and a DMSO refining tower, wherein the first-stage dehydration tower is connected with the primary distillation intermediate tank, the wiped film evaporator is connected with the primary distillation intermediate tank, and then the primary distillation intermediate tank, the second-stage dehydration tower and the DMSO rectifying tower are sequentially connected. The dimethyl sulfoxide raw material is divided into two strands, the low-concentration DMSO raw material does not contain high polymers, the DMSO content is 2-15%, the low-concentration DMSO raw material directly enters a first-stage dehydration tower, and most of water in the raw material is removed; the high-concentration DMSO raw material contains high polymer, the DMSO content is 22-50%, and the high polymer is removed by a wiped film evaporator and then enters a secondary dehydration tower together with the dehydrated low-concentration raw material.
The technical scheme requires complicated equipment, has higher equipment cost, and does not relate to the recovery of DMSO from organic waste liquid.
In the semiconductor manufacturing process, a large amount of propylene glycol methyl ether, propylene glycol methyl ether acetate and dimethyl sulfoxide are used for cleaning electronic components, and organic waste liquid containing the substances such as propylene glycol methyl ether, propylene glycol methyl ether acetate, dimethyl sulfoxide, water, alkali, particles and the like is generated after cleaning. In the conventional method, propylene glycol methyl ether and propylene glycol methyl ether acetate are directly separated and recovered from organic waste liquid, and are further treated to be used as a diluent for cleaning redundant photoresist of glass and silicon wafers in the semiconductor manufacturing process; but does not relate to the separation and recovery of the dimethyl sulfoxide with higher content.
CN112142630A discloses a method for recovering dimethyl sulfoxide from waste liquid in semiconductor industry, which comprises the steps of firstly, conveying the waste liquid of dimethyl sulfoxide into a scraper evaporator for reduced pressure evaporation to remove particles, photoresist and alkali; then, water is added for mixing, and the mixture is sent to a batch distillation tower kettle. Firstly, a mixture of propylene glycol methyl ether, propylene glycol methyl ether acetate and water is obtained at the top of the rectifying tower; and then respectively obtaining excessive fraction mixed by water and dimethyl sulfoxide and a dimethyl sulfoxide finished product. Although the above method can recover dimethyl sulfoxide, it cannot recover dimethyl sulfoxide, propylene glycol monomethyl ether and propylene glycol methyl ether acetate separately, and the recovery cost needs to be further reduced.
Therefore, it is necessary to provide a method for separately recovering dimethyl sulfoxide, propylene glycol monomethyl ether and propylene glycol methyl ether acetate in an organic solvent.
Disclosure of Invention
Aiming at the defects in the prior art, the invention aims to provide a method for recovering dimethyl sulfoxide from a waste organic solvent, which can realize the respective recovery of dimethyl sulfoxide, propylene glycol monomethyl ether and propylene glycol methyl ether acetate in the waste organic solvent, further improve the economic benefit of separating and recovering the dimethyl sulfoxide and has extremely high industrial application value.
In order to achieve the purpose, the invention adopts the following technical scheme:
in a first aspect, the present invention provides a method for recovering dimethyl sulfoxide from a waste organic solvent, the waste organic solvent comprising dimethyl sulfoxide, propylene glycol monomethyl ether and propylene glycol methyl ether acetate, the method comprising the steps of:
(1) carrying out first vacuum rectification treatment on the waste organic solvent, and recovering a fraction at 78-82 ℃ to obtain propylene glycol monomethyl ether;
(2) performing second vacuum rectification, and separating to obtain a first mixture of propylene glycol monomethyl ether and propylene glycol methyl ether acetate so as to remove residual propylene glycol monomethyl ether;
(3) carrying out third vacuum rectification to separate 108-112 ℃ fractions to obtain propylene glycol monomethyl ether acetate;
(4) performing fourth vacuum rectification, and separating to obtain a second mixture of propylene glycol methyl ether acetate and dimethyl sulfoxide to remove residual propylene glycol methyl ether acetate;
(5) performing fifth vacuum rectification to recover the fraction at 114-116 ℃ to obtain the dimethyl sulfoxide.
The method realizes the respective recovery of dimethyl sulfoxide, propylene glycol monomethyl ether and propylene glycol methyl ether acetate in the waste organic solvent by accurately controlling the conditions of the first vacuum rectification, the second vacuum rectification, the third vacuum rectification, the fourth vacuum rectification and the fifth vacuum rectification. Moreover, the method ensures the purity of the propylene glycol monomethyl ether acetate and the dimethyl sulfoxide through the arrangement of the second reduced pressure distillation and the fourth reduced pressure distillation, and is convenient for direct reuse.
The method provided by the invention recovers the fraction with the temperature of 78-82 ℃ in the step (1), thereby ensuring the purity and recovery rate of the propylene glycol monomethyl ether; the fraction with the temperature of 108-112 ℃ is recovered in the step (3), so that the purity and the recovery rate of the propylene glycol monomethyl ether acetate are ensured.
The second vacuum distillation has the function of removing residual propylene glycol monomethyl ether, and the conditions of the second vacuum distillation only need to realize the removal of the propylene glycol monomethyl ether.
The fourth vacuum distillation of the invention has the function of removing residual propylene glycol monomethyl ether acetate, and the condition of the fourth vacuum distillation is only required to be capable of removing the propylene glycol monomethyl ether acetate.
The recovery of the fraction at 78 to 82 ℃ in the step (1) of the present invention means that the overhead temperature at the time of recovering the fraction is 78 to 82 ℃ and may be, for example, 78 ℃, 79 ℃, 80 ℃, 81 ℃ or 82 ℃, but is not limited to the recited values, and other values not recited in the numerical range are also applicable.
The fraction at 108-112 ℃ recovered in step (3) of the present invention means that the overhead temperature of the fraction at 108-112 ℃ is 108-, 109 ℃, 110 ℃, 111 ℃ or 112 ℃ and can be, for example, 108 ℃, 109 ℃, 110 ℃, 111 ℃ or 112 ℃, but is not limited to the recited values, and other unrecited values in the range of values are also applicable.
The fraction recovered at 114-116 ℃ in step (5) of the present invention means that the overhead temperature at the time of recovering the fraction is 114-116 ℃, and may be, for example, 114 ℃, 115 ℃ or 116 ℃, but is not limited to the values listed, and other values not listed in the numerical range are also applicable.
Preferably, the absolute pressure of the first vacuum distillation in step (1) is 0.018-0.022MPa, for example 0.018MPa, 0.019MPa, 0.02MPa, 0.021MPa or 0.022MPa, but is not limited to the values listed, and other values not listed in the numerical range are equally applicable.
Preferably, the reflux ratio of the first vacuum distillation in step (1) is (2-5):1, and may be, for example, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1 or 5:1, but is not limited to the recited values, and other values not recited in the numerical range are also applicable.
Preferably, the absolute pressure of the second vacuum distillation in the step (2) is 0.018-0.022MPa, such as 0.018MPa, 0.019MPa, 0.02MPa, 0.021MPa or 0.022MPa, but not limited to the recited values, and other values in the range of the values are also applicable.
Preferably, the reflux ratio of the second vacuum distillation in step (2) is 5 (1-3), and may be, for example, 5:1, 5:1.5, 5:2, 5:2.5 or 5:3, but is not limited to the enumerated values, and other values not enumerated in the numerical range are also applicable.
The time of the second vacuum rectification is not further limited, so long as the residual propylene glycol monomethyl ether can be removed.
Preferably, the absolute pressure of the third vacuum distillation in the step (3) is 0.018-0.022MPa, for example, 0.018MPa, 0.019MPa, 0.02MPa, 0.021MPa or 0.022MPa, but the absolute pressure is not limited to the values listed, and other values not listed in the numerical range are also applicable.
Preferably, the reflux ratio of the third vacuum distillation in step (3) is (2-6):1, and may be, for example, 2:1, 3:1, 4:1, 5:1 or 6:1, but is not limited to the recited values, and other values not recited in the numerical range are also applicable.
Preferably, the absolute pressure of the fourth vacuum distillation in step (4) is 0.001-0.003MPa, such as 0.001MPa, 0.002MPa or 0.003MPa, but not limited to the values listed, and other values not listed in the numerical range are equally applicable.
Preferably, the reflux ratio of the fourth vacuum distillation in step (4) is 5 (1-4), and may be, for example, 5:1, 5:1.5, 5:2, 5:2.5, 5:3, 5:3.5 or 5:4, but is not limited to the enumerated values, and other values not enumerated in the numerical range are also applicable.
The time of the fourth vacuum rectification is not further limited, so long as the residual propylene glycol monomethyl ether acetate can be removed.
Preferably, the absolute pressure of the fifth vacuum distillation in step (5) is 0.001-0.003MPa, such as 0.001MPa, 0.002MPa or 0.003MPa, but not limited to the values listed, and other values not listed in the numerical range are equally applicable.
Preferably, the reflux ratio of the fifth vacuum distillation of step (5) is (1.2-2):1, for example 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1 or 2:1, but is not limited to the values listed, and other values not listed in the numerical range apply as well.
Preferably, the first mixture obtained in step (2) and/or the second mixture obtained in step (4) are recycled to step (1).
According to the invention, the first mixture and/or the second mixture are/is reused as the waste organic solvent, so that the recovery rates of propylene glycol monomethyl ether, propylene glycol methyl ether acetate and dimethyl sulfoxide are improved.
Preferably, in the waste organic solvent in the step (1), the mass percent of the dimethyl sulfoxide is 20-40 wt%, the mass percent of the propylene glycol monomethyl ether is 27-35 wt%, the mass percent of the propylene glycol methyl ether acetate is 32-35 wt%, and the balance is inevitable impurities.
The mass percentage of dimethyl sulfoxide in the waste organic solvent in step (1) of the present invention is 20 to 40 wt%, and may be, for example, 20 wt%, 25 wt%, 30 wt%, 35 wt%, or 40 wt%, but is not limited to the recited values, and other values not recited in the range of values are also applicable.
The mass percentage of propylene glycol monomethyl ether in the waste organic solvent of step (1) of the present invention is 27 to 35 wt%, and may be, for example, 27 wt%, 28 wt%, 30 wt%, 32 wt%, 33 wt%, or 35 wt%, but is not limited to the recited values, and other values not recited in the numerical range are also applicable.
The mass percentage of propylene glycol monomethyl ether acetate in the waste organic solvent of step (1) of the present invention is 32 to 35 wt%, and may be, for example, 32 wt%, 32.5 wt%, 33 wt%, 33.5 wt%, 34 wt%, 34.5 wt%, or 35 wt%, but is not limited to the recited values, and other values not recited in the range of values are also applicable.
Preferably, the process is carried out in a rectification column.
The method provided by the invention can be carried out only by a rectifying tower, and has low requirements on equipment.
The rectification column of the present invention is preferably a vacuum rectification column, and the present invention is not limited herein.
As a preferred technical scheme of the method, the method comprises the following steps:
(1) carrying out first vacuum rectification treatment on the waste organic solvent, and recovering a fraction at 78-82 ℃ to obtain propylene glycol monomethyl ether; absolute pressure of the first vacuum rectification is 0.018-0.022MPa, and reflux ratio of the first vacuum rectification is (2-5): 1;
in the waste organic solvent, the mass percent of dimethyl sulfoxide is 20-40 wt%, the mass percent of propylene glycol monomethyl ether is 27-35 wt%, and the mass percent of propylene glycol methyl ether acetate is 32-35 wt%;
(2) performing second vacuum rectification, and separating to obtain a first mixture of propylene glycol monomethyl ether and propylene glycol methyl ether acetate so as to remove residual propylene glycol monomethyl ether; absolute pressure of the second vacuum rectification is 0.018-0.022MPa, and reflux ratio of the second vacuum rectification is 5 (1-3);
(3) performing third vacuum distillation to separate the fraction at the temperature of 108-112 ℃ to obtain propylene glycol monomethyl ether acetate; the absolute pressure of the third vacuum rectification is 0.018-0.022MPa, and the reflux ratio of the third vacuum rectification is (2-6): 1;
(4) performing fourth vacuum rectification, and separating to obtain a second mixture of propylene glycol methyl ether acetate and dimethyl sulfoxide to remove residual propylene glycol methyl ether acetate; the absolute pressure of the fourth vacuum rectification is 0.001-0.003MPa, and the reflux ratio of the fourth vacuum rectification is 5 (1-4);
(5) performing fifth vacuum rectification to recover the fraction at 114 ℃ and 116 ℃ to obtain dimethyl sulfoxide; the absolute pressure of the fifth vacuum distillation is 0.001-0.003MPa, and the reflux ratio of the fifth vacuum distillation is (1.2-2): 1.
The numerical ranges set forth herein include not only the recited values but also any values between the recited numerical ranges not enumerated herein, and are not intended to be exhaustive or otherwise clear from the intended disclosure of the invention in view of brevity and clarity.
Compared with the prior art, the invention has the beneficial effects that:
(1) according to the invention, by controlling the conditions in the rectification process, the separation of dimethyl sulfoxide, propylene glycol monomethyl ether and propylene glycol methyl ether acetate can be realized, the economic benefit of separating and recovering dimethyl sulfoxide is further improved, and the method has extremely high industrial application value;
(2) when the method provided by the invention separates and recovers dimethyl sulfoxide, propylene glycol monomethyl ether and propylene glycol methyl ether acetate in the waste organic solvent, the recovery rate of the dimethyl sulfoxide can reach 80.3%, and the purity is more than 99.8 wt%; the recovery rate of the propylene glycol monomethyl ether can reach 81.3 percent, and the purity is more than 99.9 weight percent; the recovery rate of the propylene glycol monomethyl ether acetate can reach 78.8 percent, and the purity is more than 99.9 weight percent.
Detailed Description
The technical solution of the present invention is further explained by the following embodiments.
Example 1
This example provides a process for recovering dimethyl sulfoxide from a spent organic solvent, comprising the steps of:
(1) carrying out first vacuum rectification treatment on the waste organic solvent, and recovering a fraction at 78-82 ℃ to obtain propylene glycol monomethyl ether; the absolute pressure of the first vacuum rectification is 0.02MPa, and the reflux ratio of the first vacuum rectification is 4: 1;
in the waste organic solvent, the mass percent of dimethyl sulfoxide is 30 wt%, the mass percent of propylene glycol monomethyl ether is 32 wt%, the mass percent of propylene glycol methyl ether acetate is 33 wt%, and the balance is impurities;
(2) performing second reduced pressure rectification, and separating to obtain a first mixture of propylene glycol monomethyl ether and propylene glycol methyl ether acetate so as to remove residual propylene glycol monomethyl ether; the absolute pressure of the second reduced pressure distillation is 0.02MPa, and the reflux ratio of the second reduced pressure distillation is 5: 2;
(3) carrying out third vacuum rectification to separate 108-112 ℃ fractions to obtain propylene glycol monomethyl ether acetate; the absolute pressure of the third vacuum rectification is 0.02MPa, and the reflux ratio of the third vacuum rectification is 4: 1;
(4) performing fourth vacuum rectification, and separating to obtain a second mixture of propylene glycol methyl ether acetate and dimethyl sulfoxide to remove residual propylene glycol methyl ether acetate; the absolute pressure of the fourth vacuum rectification is 0.002MPa, and the reflux ratio of the fourth vacuum rectification is 5: 3;
(5) performing fifth vacuum rectification to recover the fraction at 114 ℃ and 116 ℃ and obtain dimethyl sulfoxide; the absolute pressure of the fifth vacuum rectification is 0.002MPa, and the reflux ratio of the fifth vacuum rectification is 1.5: 1.
Example 2
This example provides a process for recovering dimethyl sulfoxide from a spent organic solvent, comprising the steps of:
(1) carrying out first vacuum rectification treatment on the waste organic solvent, and recovering a fraction at 78-82 ℃ to obtain propylene glycol monomethyl ether; the absolute pressure of the first vacuum rectification is 0.018MPa, and the reflux ratio of the first vacuum rectification is 2: 1;
the composition of the waste organic solvent was the same as in example 1;
(2) performing second vacuum rectification, and separating to obtain a first mixture of propylene glycol monomethyl ether and propylene glycol methyl ether acetate so as to remove residual propylene glycol monomethyl ether; absolute pressure of the second vacuum rectification is 0.018MPa, and reflux ratio of the second vacuum rectification is 5: 1;
(3) carrying out third vacuum rectification to separate 108-112 ℃ fractions to obtain propylene glycol monomethyl ether acetate; the absolute pressure of the third vacuum rectification is 0.018MPa, and the reflux ratio of the third vacuum rectification is 2: 1;
(4) performing fourth vacuum rectification, and separating to obtain a second mixture of propylene glycol methyl ether acetate and dimethyl sulfoxide to remove residual propylene glycol methyl ether acetate; the absolute pressure of the fourth vacuum rectification is 0.001MPa, and the reflux ratio of the fourth vacuum rectification is 5: 1;
(5) performing fifth vacuum rectification to recover the fraction at 114 ℃ and 116 ℃ and obtain dimethyl sulfoxide; the absolute pressure of the fifth vacuum rectification is 0.001MPa, and the reflux ratio of the fifth vacuum rectification is 1.2: 1.
Example 3
This example provides a process for recovering dimethyl sulfoxide from a spent organic solvent, comprising the steps of:
(1) carrying out first vacuum rectification treatment on the waste organic solvent, and recovering a fraction at 78-82 ℃ to obtain propylene glycol monomethyl ether; the absolute pressure of the first vacuum rectification is 0.022MPa, and the reflux ratio of the first vacuum rectification is 5: 1;
the composition of the waste organic solvent was the same as in example 1;
(2) performing second reduced pressure rectification, and separating to obtain a first mixture of propylene glycol monomethyl ether and propylene glycol methyl ether acetate so as to remove residual propylene glycol monomethyl ether; absolute pressure of the second vacuum distillation is 0.022MPa, and reflux ratio of the second vacuum distillation is 5: 3;
(3) carrying out third vacuum rectification to separate 108-112 ℃ fractions to obtain propylene glycol monomethyl ether acetate; the absolute pressure of the third vacuum rectification is 0.022MPa, and the reflux ratio of the third vacuum rectification is 6: 1;
(4) performing fourth vacuum rectification, and separating to obtain a second mixture of propylene glycol methyl ether acetate and dimethyl sulfoxide to remove residual propylene glycol methyl ether acetate; the absolute pressure of the fourth vacuum rectification is 0.003MPa, and the reflux ratio of the fourth vacuum rectification is 5: 4;
(5) performing fifth vacuum rectification to recover the fraction at 114 ℃ and 116 ℃ and obtain dimethyl sulfoxide; the absolute pressure of the fifth vacuum distillation is 0.003MPa, and the reflux ratio of the fifth vacuum distillation is 2: 1.
Example 4
This example provides a method for recovering dimethyl sulfoxide from waste organic solvent, which is the same as example 1 except that the mass percent of dimethyl sulfoxide is 20 wt%, the mass percent of propylene glycol monomethyl ether is 35 wt%, and the mass percent of propylene glycol methyl ether acetate is 35 wt% in the waste organic solvent.
Example 5
This example provides a method for recovering dimethyl sulfoxide from waste organic solvent, which is the same as example 1 except that the waste organic solvent is treated to have a dimethyl sulfoxide mass percentage of 40 wt%, propylene glycol monomethyl ether mass percentage of 27 wt%, and propylene glycol methyl ether acetate mass percentage of 32 wt%.
Example 6
This example provides a process for recovering dimethyl sulfoxide from waste organic solvents, which is the same as example 1 except that the reflux ratio in step (1) is 1.5: 1.
Example 7
This example provides a process for recovering dimethyl sulfoxide from a waste organic solvent, which is the same as example 1 except that the reflux ratio of step (1) is 5.5: 1.
Example 8
This example provides a process for recovering dimethyl sulfoxide from a waste organic solvent, which is the same as example 1 except that the reflux ratio of step (2) is 5: 3.5.
Example 9
This example provides a process for recovering dimethyl sulfoxide from a waste organic solvent, which is the same as example 1 except that the reflux ratio of step (2) is 5: 0.5.
Example 10
This example provides a process for recovering dimethyl sulfoxide from a waste organic solvent, which is the same as example 1 except that the reflux ratio of step (3) is 1.5: 1.
Example 11
This example provides a process for recovering dimethyl sulfoxide from waste organic solvent, which is the same as example 1 except that the reflux ratio of step (3) is 6.5: 1.
Example 12
This example provides a process for recovering dimethyl sulfoxide from a waste organic solvent, which is the same as example 1 except that the reflux ratio of step (4) is 5: 0.5.
Example 13
This example provides a process for recovering dimethyl sulfoxide from waste organic solvent, which is the same as example 1 except that the reflux ratio of step (4) is 5: 4.5.
Example 14
This example provides a process for recovering dimethyl sulfoxide from a waste organic solvent, which is the same as example 1 except that the reflux ratio of step (5) is 1: 1.
Example 15
This example provides a process for recovering dimethyl sulfoxide from a waste organic solvent, which is the same as example 1 except that the reflux ratio of step (5) is 2.2: 1.
Comparative example 1
This comparative example provides a process for recovering dimethyl sulfoxide from a spent organic solvent, comprising the steps of:
(I) carrying out first vacuum rectification treatment on the waste organic solvent, and recovering a fraction at 78-82 ℃ to obtain propylene glycol monomethyl ether; the absolute pressure of the first vacuum rectification is 0.02MPa, and the reflux ratio of the first vacuum rectification is 4: 1;
in the waste organic solvent, the mass percent of dimethyl sulfoxide is 30 wt%, the mass percent of propylene glycol monomethyl ether is 32 wt%, the mass percent of propylene glycol methyl ether acetate is 33 wt%, and the balance is impurities;
(II) carrying out third vacuum rectification to separate a fraction at the temperature of 108-112 ℃ to obtain propylene glycol monomethyl ether acetate; the absolute pressure of the third vacuum rectification is 0.02MPa, and the reflux ratio of the third vacuum rectification is 4: 1;
(III) carrying out fourth vacuum rectification, and separating to obtain a second mixture of propylene glycol methyl ether acetate and dimethyl sulfoxide to remove residual propylene glycol methyl ether acetate; the absolute pressure of the fourth vacuum rectification is 0.002MPa, and the reflux ratio of the fourth vacuum rectification is 5: 3;
(IV) carrying out fifth vacuum distillation, recovering the fraction at 114-116 ℃, and recovering to obtain dimethyl sulfoxide; the absolute pressure of the fifth vacuum rectification is 0.002MPa, and the reflux ratio of the fifth vacuum rectification is 1.5: 1.
Comparative example 2
This comparative example provides a process for recovering dimethyl sulfoxide from a spent organic solvent, comprising the steps of:
(a) carrying out first vacuum rectification treatment on the waste organic solvent, and recovering a fraction at 78-82 ℃ to obtain propylene glycol monomethyl ether; the absolute pressure of the first vacuum rectification is 0.02MPa, and the reflux ratio of the first vacuum rectification is 4: 1;
in the waste organic solvent, the mass percent of dimethyl sulfoxide is 30 wt%, the mass percent of propylene glycol monomethyl ether is 32 wt%, the mass percent of propylene glycol methyl ether acetate is 33 wt%, and the balance is impurities;
(b) performing second vacuum rectification, and separating to obtain a first mixture of propylene glycol monomethyl ether and propylene glycol methyl ether acetate so as to remove residual propylene glycol monomethyl ether; absolute pressure of the second vacuum distillation is 0.02MPa, and reflux ratio of the second vacuum distillation is 5: 2;
(c) performing third vacuum distillation to separate the fraction at the temperature of 108-112 ℃ to obtain propylene glycol monomethyl ether acetate; the absolute pressure of the third vacuum rectification is 0.02MPa, and the reflux ratio of the third vacuum rectification is 4: 1;
(d) performing fifth vacuum rectification to recover the fraction at 114 ℃ and 116 ℃ and obtain dimethyl sulfoxide; the absolute pressure of the fifth vacuum rectification is 0.002MPa, and the reflux ratio of the fifth vacuum rectification is 1.5: 1.
The purity of dimethyl sulfoxide, propylene glycol monomethyl ether and propylene glycol methyl ether acetate obtained in the examples and comparative examples, and the recovery rate of dimethyl sulfoxide, propylene glycol monomethyl ether and propylene glycol methyl ether acetate were measured, and the results are shown in table 1.
TABLE 1
In conclusion, the invention can realize the separation of dimethyl sulfoxide, propylene glycol monomethyl ether and propylene glycol methyl ether acetate by controlling the conditions in the rectification process, further improves the economic benefit of separating and recovering dimethyl sulfoxide, and has extremely high industrial application value; when the method provided by the invention separates and recovers dimethyl sulfoxide, propylene glycol monomethyl ether and propylene glycol methyl ether acetate in the waste organic solvent, the recovery rate of the dimethyl sulfoxide can reach 80.3%, and the purity is more than 99.8 wt%; the recovery rate of the propylene glycol monomethyl ether can reach 81.3 percent, and the purity is more than 99.9 weight percent; the recovery rate of the propylene glycol monomethyl ether acetate can reach 78.8 percent, and the purity is more than 99.9 weight percent.
The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are only exemplary embodiments of the present invention, and are not intended to limit the present invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. A method for recovering dimethyl sulfoxide from waste organic solvent, wherein the waste organic solvent comprises dimethyl sulfoxide, propylene glycol monomethyl ether and propylene glycol methyl ether acetate, and the method is characterized by comprising the following steps:
(1) carrying out first vacuum rectification treatment on the waste organic solvent, and recovering a fraction at 78-82 ℃ to obtain propylene glycol monomethyl ether;
(2) performing second vacuum rectification, and separating to obtain a first mixture of propylene glycol monomethyl ether and propylene glycol methyl ether acetate so as to remove residual propylene glycol monomethyl ether;
(3) performing third vacuum distillation to separate the fraction at the temperature of 108-112 ℃ to obtain propylene glycol monomethyl ether acetate;
(4) performing fourth vacuum rectification, and separating to obtain a second mixture of propylene glycol methyl ether acetate and dimethyl sulfoxide to remove residual propylene glycol methyl ether acetate;
(5) performing fifth vacuum rectification to recover the fraction at 114-116 ℃ to obtain the dimethyl sulfoxide.
2. The process according to claim 1, wherein the absolute pressure of the first vacuum distillation in the step (1) is 0.018-0.022 MPa;
preferably, the reflux ratio of the first vacuum distillation in the step (1) is (2-5): 1.
3. The process according to claim 1 or 2, wherein the absolute pressure of the second vacuum distillation of step (2) is 0.018-0.022 MPa;
preferably, the reflux ratio of the second vacuum distillation in the step (2) is 5 (1-3).
4. The process according to any one of claims 1 to 3, wherein the absolute pressure of the third vacuum distillation of step (3) is 0.018 to 0.022 MPa;
preferably, the reflux ratio of the third vacuum rectification in the step (3) is (2-6): 1.
5. The process according to any one of claims 1 to 4, wherein the absolute pressure of the fourth vacuum distillation in the step (4) is from 0.001 to 0.003 MPa;
preferably, the reflux ratio of the fourth vacuum distillation in the step (4) is 5 (1-4).
6. The process according to any one of claims 1 to 5, wherein the absolute pressure of the fifth vacuum distillation in the step (5) is from 0.001 to 0.003 MPa;
preferably, the reflux ratio of the fifth vacuum rectification in the step (5) is (1.2-2): 1.
7. The process according to any one of claims 1 to 6, wherein the first mixture obtained in step (2) and/or the second mixture obtained in step (4) is recycled to step (1).
8. The method according to any one of claims 1 to 7, wherein in the waste organic solvent of step (1), the mass percent of dimethyl sulfoxide is 20 to 40 wt%, the mass percent of propylene glycol monomethyl ether is 27 to 35 wt%, the mass percent of propylene glycol methyl ether acetate is 32 to 35 wt%, and the balance is inevitable impurities.
9. A method according to any of claims 1-8, characterized in that the method is carried out in a rectification column.
10. A method according to any of claims 1-9, characterized in that the method comprises the steps of:
(1) carrying out first vacuum rectification treatment on the waste organic solvent, and recovering a fraction at 78-82 ℃ to obtain propylene glycol monomethyl ether; absolute pressure of the first vacuum rectification is 0.018-0.022MPa, and reflux ratio of the first vacuum rectification is (2-5): 1;
in the waste organic solvent, the mass percent of dimethyl sulfoxide is 20-40 wt%, the mass percent of propylene glycol monomethyl ether is 27-35 wt%, and the mass percent of propylene glycol methyl ether acetate is 32-35 wt%;
(2) performing second vacuum rectification, and separating to obtain a first mixture of propylene glycol monomethyl ether and propylene glycol methyl ether acetate so as to remove residual propylene glycol monomethyl ether; absolute pressure of the second vacuum rectification is 0.018-0.022MPa, and reflux ratio of the second vacuum rectification is 5 (1-3);
(3) carrying out third vacuum rectification to separate 108-112 ℃ fractions to obtain propylene glycol monomethyl ether acetate; the absolute pressure of the third vacuum rectification is 0.018-0.022MPa, and the reflux ratio of the third vacuum rectification is (2-6): 1;
(4) performing fourth vacuum rectification, and separating to obtain a second mixture of propylene glycol methyl ether acetate and dimethyl sulfoxide to remove residual propylene glycol methyl ether acetate; the absolute pressure of the fourth vacuum rectification is 0.001-0.003MPa, and the reflux ratio of the fourth vacuum rectification is 5 (1-4);
(5) performing fifth vacuum rectification to recover the fraction at 114 ℃ and 116 ℃ to obtain dimethyl sulfoxide; the absolute pressure of the fifth vacuum distillation is 0.001-0.003MPa, and the reflux ratio of the fifth vacuum distillation is (1.2-2): 1.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001089438A (en) * | 1999-09-24 | 2001-04-03 | Toray Fine Chemicals Co Ltd | Method for recovering dimethylsulfoxide |
| CN103387307A (en) * | 2013-08-08 | 2013-11-13 | 王岚 | Method for processing organic waste liquor in electronic manufacturing industry |
| CN112142630A (en) * | 2020-10-28 | 2020-12-29 | 雅邦绿色过程与新材料研究院南京有限公司 | Method for recovering dimethyl sulfoxide from semiconductor industrial waste liquid |
| CN114213290A (en) * | 2021-12-30 | 2022-03-22 | 无锡中天固废处置有限公司 | Separation and purification process of DMSO (dimethyl sulfoxide) -containing organic waste liquid |
| CN114409500A (en) * | 2022-01-25 | 2022-04-29 | 福建钰融科技有限公司 | Method for recovering propylene glycol methyl ether and propylene glycol monomethyl ether acetate from electronic waste liquid |
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Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001089438A (en) * | 1999-09-24 | 2001-04-03 | Toray Fine Chemicals Co Ltd | Method for recovering dimethylsulfoxide |
| CN103387307A (en) * | 2013-08-08 | 2013-11-13 | 王岚 | Method for processing organic waste liquor in electronic manufacturing industry |
| CN112142630A (en) * | 2020-10-28 | 2020-12-29 | 雅邦绿色过程与新材料研究院南京有限公司 | Method for recovering dimethyl sulfoxide from semiconductor industrial waste liquid |
| CN114213290A (en) * | 2021-12-30 | 2022-03-22 | 无锡中天固废处置有限公司 | Separation and purification process of DMSO (dimethyl sulfoxide) -containing organic waste liquid |
| CN114409500A (en) * | 2022-01-25 | 2022-04-29 | 福建钰融科技有限公司 | Method for recovering propylene glycol methyl ether and propylene glycol monomethyl ether acetate from electronic waste liquid |
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