CN112500933A - Process for purification of crude fatty acids - Google Patents
Process for purification of crude fatty acids Download PDFInfo
- Publication number
- CN112500933A CN112500933A CN202011308255.6A CN202011308255A CN112500933A CN 112500933 A CN112500933 A CN 112500933A CN 202011308255 A CN202011308255 A CN 202011308255A CN 112500933 A CN112500933 A CN 112500933A
- Authority
- CN
- China
- Prior art keywords
- fatty acid
- vacuum distillation
- impurities
- crude
- purified
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 235000014113 dietary fatty acids Nutrition 0.000 title claims abstract description 117
- 229930195729 fatty acid Natural products 0.000 title claims abstract description 117
- 239000000194 fatty acid Substances 0.000 title claims abstract description 117
- 150000004665 fatty acids Chemical class 0.000 title claims abstract description 116
- 238000000034 method Methods 0.000 title claims abstract description 32
- 238000000746 purification Methods 0.000 title claims abstract description 30
- 239000012535 impurity Substances 0.000 claims abstract description 50
- 238000005292 vacuum distillation Methods 0.000 claims abstract description 41
- 239000012264 purified product Substances 0.000 claims abstract description 19
- 238000007872 degassing Methods 0.000 claims abstract description 17
- 238000004821 distillation Methods 0.000 claims description 14
- PEDCQBHIVMGVHV-UHFFFAOYSA-N Glycerine Chemical compound OCC(O)CO PEDCQBHIVMGVHV-UHFFFAOYSA-N 0.000 claims description 9
- 238000010438 heat treatment Methods 0.000 claims description 6
- 150000001299 aldehydes Chemical class 0.000 claims description 3
- 125000005456 glyceride group Chemical group 0.000 claims description 3
- 150000002576 ketones Chemical class 0.000 claims description 3
- 239000000049 pigment Substances 0.000 claims description 3
- 239000000413 hydrolysate Substances 0.000 claims description 2
- 239000000047 product Substances 0.000 abstract description 8
- 230000009286 beneficial effect Effects 0.000 abstract description 3
- 239000000523 sample Substances 0.000 description 10
- 238000007701 flash-distillation Methods 0.000 description 3
- 239000012521 purified sample Substances 0.000 description 3
- 238000009835 boiling Methods 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 235000019198 oils Nutrition 0.000 description 2
- 238000011084 recovery Methods 0.000 description 2
- 241001465754 Metazoa Species 0.000 description 1
- 238000009874 alkali refining Methods 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 201000010099 disease Diseases 0.000 description 1
- 208000037265 diseases, disorders, signs and symptoms Diseases 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 125000005313 fatty acid group Chemical group 0.000 description 1
- 235000021323 fish oil Nutrition 0.000 description 1
- 235000021588 free fatty acids Nutrition 0.000 description 1
- 239000010806 kitchen waste Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 238000010992 reflux Methods 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
- C11C—FATTY ACIDS FROM FATS, OILS OR WAXES; CANDLES; FATS, OILS OR FATTY ACIDS BY CHEMICAL MODIFICATION OF FATS, OILS, OR FATTY ACIDS OBTAINED THEREFROM
- C11C1/00—Preparation of fatty acids from fats, fatty oils, or waxes; Refining the fatty acids
- C11C1/08—Refining
- C11C1/10—Refining by distillation
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D19/00—Degasification of liquids
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
- B01D3/10—Vacuum distillation
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
- C07C51/42—Separation; Purification; Stabilisation; Use of additives
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
- C07C51/42—Separation; Purification; Stabilisation; Use of additives
- C07C51/43—Separation; Purification; Stabilisation; Use of additives by change of the physical state, e.g. crystallisation
- C07C51/44—Separation; Purification; Stabilisation; Use of additives by change of the physical state, e.g. crystallisation by distillation
-
- C—CHEMISTRY; METALLURGY
- C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
- C11C—FATTY ACIDS FROM FATS, OILS OR WAXES; CANDLES; FATS, OILS OR FATTY ACIDS BY CHEMICAL MODIFICATION OF FATS, OILS, OR FATTY ACIDS OBTAINED THEREFROM
- C11C1/00—Preparation of fatty acids from fats, fatty oils, or waxes; Refining the fatty acids
- C11C1/08—Refining
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Microbiology (AREA)
- General Chemical & Material Sciences (AREA)
- Wood Science & Technology (AREA)
- Crystallography & Structural Chemistry (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Fats And Perfumes (AREA)
Abstract
The application relates to the technical field of fatty acid purification, and provides a crude fatty acid purification method. The purification method provided by the application comprises the following steps: degassing the crude fatty acid to obtain a first purified product; subjecting the first purified product to vacuum distillation to remove light fraction impurities and heavy fraction impurities and collecting purified fatty acids; wherein the temperature of the vacuum distillation treatment is 200-240 ℃, and the vacuum degree is more than or equal to 0.095 Mpa. By the method, light fraction impurities and heavy fraction impurities in the crude fatty acid are effectively removed, the influence of the impurities on the service performance of the fatty acid product can be avoided, and the quality of the fatty acid product is improved. The method has simple process and simple and convenient operation, is easy to realize large-scale purification of the crude fatty acid, and is beneficial to reducing the purification cost.
Description
Technical Field
The application belongs to the technical field of fatty acid purification, and particularly relates to a crude fatty acid purification method.
Background
In the process of preparing industrial fatty acid by utilizing kitchen waste and animals and plants died of diseases, the primarily obtained crude fatty acid generally contains a plurality of impurities, such as moisture, ketone, aldehyde, free glycerol, pigment, glyceride, oxidized fatty acid, unsaponifiable matter, partially polymerized fatty acid and the like, and the existence of the impurities can influence the service performance of the industrial fatty acid.
Disclosure of Invention
The application aims to provide a method for purifying crude fatty acid, and aims to solve the problem that the use performance of industrial fatty acid is influenced due to impurities in the existing crude fatty acid.
The technical scheme adopted by the application is as follows:
a process for the purification of crude fatty acids comprising the steps of:
degassing the crude fatty acid to obtain a first purified product;
subjecting the first purified product to vacuum distillation to remove light fraction impurities and heavy fraction impurities and collecting purified fatty acids;
wherein the temperature of the vacuum distillation treatment is 200-240 ℃, and the vacuum degree is more than or equal to 0.095 Mpa.
According to the purification method of the crude fatty acid, the crude fatty acid is degassed firstly, and then is subjected to vacuum distillation at 200-240 ℃ and 0.095Mpa, so that light fraction impurities and heavy fraction impurities in the crude fatty acid are effectively removed, the influence of the impurities on the service performance of a fatty acid product can be avoided, and the improvement of the quality of the fatty acid product is facilitated. The method has simple process and simple and convenient operation, is easy to realize large-scale purification of the crude fatty acid, and is beneficial to reducing the purification cost.
Detailed Description
In order to make the technical problems, technical solutions and advantageous effects to be solved by the present application more clearly apparent, the present application is further described in detail below with reference to the embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.
A process for the purification of crude fatty acids comprising the steps of:
s01, degassing the crude fatty acid to obtain a first purified product;
s02, carrying out vacuum distillation treatment on the first purified product to remove light fraction impurities and heavy fraction impurities, and collecting purified fatty acid;
wherein the temperature of the vacuum distillation treatment is 200-240 ℃, and the vacuum degree is more than or equal to 0.095 Mpa.
According to the purification method of the crude fatty acid, the crude fatty acid is degassed firstly, and then is subjected to vacuum distillation at 200-240 ℃ and 0.095Mpa, so that light fraction impurities and heavy fraction impurities in the crude fatty acid are effectively removed, the influence of the impurities on the service performance of a fatty acid product can be avoided, and the improvement of the quality of the fatty acid product is facilitated. The method has simple process and simple and convenient operation, is easy to realize large-scale purification of the crude fatty acid, and is beneficial to reducing the purification cost.
Specifically, in step S01, the crude fatty acid is degassed to remove mainly air in the crude fatty acid, and at the same time, the air can take away a part of moisture, so that the air can be removed and at the same time, a part of moisture in the crude fatty acid can be removed. According to the embodiment of the application, the degassing treatment is carried out before the vacuum distillation treatment step, so that the fatty acid in the sample can be prevented from being oxidized due to the long-time contact with water and oxygen in the subsequent vacuum distillation treatment process, and the quality of the fatty acid product is improved to a certain extent.
In some embodiments, the step of degassing the crude fatty acid comprises: heating the crude fatty acid to 80-90 deg.C, and degassing at 80-90 deg.C under pressure of less than 150 Pa. By adjusting the process conditions, the air in the crude fatty acid can be removed to the maximum extent, and meanwhile, the phenomenon that part of target fatty acid in the crude fatty acid is evaporated in advance due to the overhigh degassing temperature can be prevented, so that the loss of the fatty acid is reduced.
In some embodiments, the crude fatty acid comprises soapstock and/or hydrolysate of soapstock, and the crude fatty acid has high impurity content, and by adopting the method provided by the embodiment of the application, the fatty acid and the impurity can be separated efficiently, so that a high-quality fatty acid product is obtained.
In step S02, the first purified product is subjected to vacuum distillation to remove light fraction impurities and heavy fraction impurities, so that the fatty acid to be collected is separated from the light fraction impurities and the heavy fraction impurities, and the fatty acid is purified, wherein the temperature of the vacuum distillation is 200 ℃ to 240 ℃, and the vacuum degree is greater than or equal to 0.095 Mpa.
In some embodiments, the vacuum distillation process is performed in a vacuum distillation column comprising: a pre-cut column for removing light-fraction impurities, a fatty acid flash column for preparing purified fatty acids, and a residue distillation column for removing heavy-fraction impurities. By adopting the vacuum distillation tower to carry out vacuum distillation treatment, various technical parameters in the process are more stable and accurate, and the instability of the process parameters caused by human factors is eliminated.
On the basis of the above embodiment, the step of subjecting the crude fatty acid to degassing treatment and the step of collecting the purified fatty acid are both performed in a vacuum distillation column, the vacuum distillation column further comprising: the device comprises a degasser used for degassing treatment and a fatty acid recoverer used for collecting fatty acid, wherein the degasser, the pre-cutting tower, the fatty acid flash tower, the residue distillation tower and the fatty acid recoverer are sequentially arranged. Therefore, the integrated purification of the crude fatty acid is realized, the purification process is greatly simplified, and the loss of the fatty acid is reduced to a certain extent.
It will be understood that the vacuum distillation column used in the examples of the present application is conventional in the art, and may be commercially available or assembled using techniques conventional in the art.
Light end impurities, which are impurities present in the crude fatty acid, having a lower boiling point relative to the fatty acid and heavy end impurities, can be removed at high reflux rates in the pre-cut column, allowing them to be volatilized before the fatty acid undergoes a first distillation in the fatty acid flash column, thereby reducing the loss of fatty acid. Heavy-fraction impurities have a higher boiling point than fatty acids, are difficult to volatilize and remove under mild distillation conditions, and in order to improve the recovery rate of fatty acids, after secondary distillation in a residue distillation tower, the residue is often squeezed to minimize the content of free fatty acids in the residue.
In some embodiments, the light-fraction impurities include at least one of moisture, ketones, aldehydes, and free glycerol.
In some embodiments, the heavy fraction impurities include at least one of pigments, glycerides, oxidized fatty acids, unsaponifiables, and polymerized fatty acids.
On the basis of the above embodiment, the purification method further includes: before the step of vacuum distillation treatment of the first purified product, the first purified product is heated to 200-240 ℃ to improve the purification efficiency and shorten the purification time.
In step S02, after the step of performing the vacuum distillation treatment, the purified fatty acid is collected.
In some embodiments, the step of collecting the purified fatty acid comprises: condensing and recovering the fatty acid at 55-65 ℃, and maintaining the temperature of the fatty acid at 55-65 ℃. The purity of the fatty acid is closely related to the cooling temperature, and the cooling temperature is controlled within the range, so that the purity of the fatty acid is improved, the requirement of the vacuum distillation tower on heat recovery is met, and the production and operation cost is greatly reduced.
The following examples illustrate the practice of the present application.
Example 1
This example provides a method for purifying crude fatty acids, comprising the steps of:
(1) taking soapstock generated in the alkali refining of the raw bran oil as a purified sample, preheating the sample to 83 ℃, introducing the sample into a degasifier of a vacuum distillation tower, and degassing under the conditions of 83 ℃ and 150Pa of air pressure to obtain a first purified product;
(2) controlling the vacuum degree of a vacuum distillation tower to be 0.095Mpa, heating the first purified product to 240 ℃, and then carrying out vacuum distillation treatment, so that light fraction impurities are separated from fatty acid in a pre-cutting tower and distilled out of the top of the vacuum distillation tower, so that primary distillation is carried out in a fatty acid flash distillation tower to prepare fatty acid, and heavy fraction impurities are removed in a residue distillation tower;
(3) the fatty acid separated from the light fraction impurities and the heavy fraction impurities is condensed and recovered at 60 ℃ and finally maintained at 60 ℃.
The total fatty acids purified in this example were tested to be 39% of the total sample and 95% pure.
Example 2
This example provides a method for purifying crude fatty acids, comprising the steps of:
(1) taking fish oil soapstock as a purified sample, preheating the sample to 89 ℃, introducing the sample into a degasser of a vacuum distillation tower, and degassing under the conditions of 89 ℃ and 100Pa of air pressure to obtain a first purified product;
(2) controlling the vacuum degree of a vacuum distillation tower to be 0.1Mpa, heating the first purified product to 210 ℃, and then carrying out vacuum distillation treatment, so that light fraction impurities are separated from fatty acid in a pre-cutting tower and distilled out of the top of the vacuum distillation tower, so that primary distillation is carried out in a fatty acid flash distillation tower to prepare fatty acid, and heavy fraction impurities are removed in a residue distillation tower;
(3) the fatty acid separated from the light fraction impurities and the heavy fraction impurities was condensed and recovered at 58 ℃ and finally maintained at 58 ℃.
The total fatty acids purified in this example were tested to be 80% of the total sample and 91% pure.
Example 3
This example provides a method for purifying crude fatty acids, comprising the steps of:
(1) taking waste oil soapstock as a purified sample, preheating the sample to 85 ℃, introducing the sample into a degasser of a vacuum distillation tower, and degassing under the conditions of 85 ℃ and 130Pa to obtain a first purified product;
(2) controlling the vacuum degree of a vacuum distillation tower to be 0.2Mpa, heating the first purified product to 230 ℃, and then carrying out vacuum distillation treatment, so that light fraction impurities are separated from fatty acid in a pre-cutting tower and distilled out of the top of the vacuum distillation tower, so that primary distillation is carried out in a fatty acid flash distillation tower to prepare fatty acid, and heavy fraction impurities are removed in a residue distillation tower;
(3) the fatty acid separated from the light fraction impurities and the heavy fraction impurities is condensed and recovered at 63 ℃ and finally maintained at 63 ℃.
The total fatty acids purified in this example were tested to be 75% of the total sample and 93% pure.
The above description is only exemplary of the present application and should not be taken as limiting the present application, as any modification, equivalent replacement, or improvement made within the spirit and principle of the present application should be included in the protection scope of the present application.
Claims (9)
1. A method for purifying crude fatty acid, comprising the steps of:
degassing the crude fatty acid to obtain a first purified product;
subjecting the first purified product to vacuum distillation to remove light fraction impurities and heavy fraction impurities and collecting purified fatty acids;
wherein the temperature of the vacuum distillation treatment is 200-240 ℃, and the vacuum degree is more than or equal to 0.095 Mpa.
2. The purification process of claim 1, wherein the step of degassing the crude fatty acid comprises: heating the crude fatty acid to 80-90 ℃, and then degassing under the conditions of 80-90 ℃ and the air pressure of less than 150 Pa.
3. The purification method of claim 1, further comprising: heating the first purified product to 200 ℃ to 240 ℃ prior to the step of subjecting the first purified product to vacuum distillation treatment.
4. The purification method of claim 1, wherein the step of collecting the purified fatty acid comprises: condensing and recovering the fatty acid at 55-65 ℃, and maintaining the temperature of the fatty acid at 55-65 ℃.
5. The purification process of claim 1, wherein the crude fatty acid comprises soapstock and/or a hydrolysate of soapstock.
6. The purification process according to any one of claims 1 to 5, wherein the vacuum distillation treatment is carried out in a vacuum distillation column comprising: a pre-cut column for removing the light fraction impurities, a fatty acid flash column for producing purified fatty acids, and a residue distillation column for removing the heavy fraction impurities.
7. The purification process of claim 6, wherein the step of degassing the crude fatty acid and the step of collecting the purified fatty acid are both performed in a vacuum distillation column, the vacuum distillation column further comprising: the degasser is used for degassing treatment, the fatty acid recoverer is used for collecting fatty acid, and the degasser, the pre-cutting tower, the fatty acid flash tower, the residue distillation tower and the fatty acid recoverer are sequentially arranged.
8. The purification process of any one of claims 1 to 5, wherein the light-end impurities comprise at least one of moisture, ketones, aldehydes, and free glycerol.
9. The purification process of any one of claims 1 to 5, wherein the heavy-cut impurities comprise at least one of pigments, glycerides, oxidized fatty acids, unsaponifiables, and polymerized fatty acids.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011308255.6A CN112500933A (en) | 2020-11-20 | 2020-11-20 | Process for purification of crude fatty acids |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011308255.6A CN112500933A (en) | 2020-11-20 | 2020-11-20 | Process for purification of crude fatty acids |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN112500933A true CN112500933A (en) | 2021-03-16 |
Family
ID=74959028
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202011308255.6A Pending CN112500933A (en) | 2020-11-20 | 2020-11-20 | Process for purification of crude fatty acids |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112500933A (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CH330135A (en) * | 1954-06-04 | 1958-05-31 | Buss Ag | Process for the production of pure fatty acids or fatty acid mixtures from raw materials containing fatty acids |
| CN1664087A (en) * | 2005-02-03 | 2005-09-07 | 朱新民 | Process for producing monomeric fatty acid |
| CN204455049U (en) * | 2015-02-11 | 2015-07-08 | 浙江华诺化工有限公司 | Soap fat fat acid distillation system |
| CN109157859A (en) * | 2018-09-25 | 2019-01-08 | 无锡科伦达化工热力装备有限公司 | A kind of fatty acid vacuum (distilling) column |
-
2020
- 2020-11-20 CN CN202011308255.6A patent/CN112500933A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CH330135A (en) * | 1954-06-04 | 1958-05-31 | Buss Ag | Process for the production of pure fatty acids or fatty acid mixtures from raw materials containing fatty acids |
| CN1664087A (en) * | 2005-02-03 | 2005-09-07 | 朱新民 | Process for producing monomeric fatty acid |
| CN204455049U (en) * | 2015-02-11 | 2015-07-08 | 浙江华诺化工有限公司 | Soap fat fat acid distillation system |
| CN109157859A (en) * | 2018-09-25 | 2019-01-08 | 无锡科伦达化工热力装备有限公司 | A kind of fatty acid vacuum (distilling) column |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP3712903B2 (en) | Method for producing glycerin | |
| CN1310903C (en) | Method for extracting natural vitamin E from vegetable oil and fat refining and deodorizing distillate | |
| EP3594317B1 (en) | Fractionation of biomass-based material | |
| EP1465968B1 (en) | Methods for treating deodorizer distillate | |
| CN107759471B (en) | Separation and purification device and process for preparing cyclohexane plasticizer product by liquid phase hydrogenation of o-benzene plasticizer | |
| WO2019214422A1 (en) | Method for extracting natural vitamin e from deodorized distillate of rice bran oil | |
| CN102775275A (en) | Refined glycerol purification process | |
| CN107445826A (en) | A kind of preparation method of neural acid esters | |
| EP4234526A1 (en) | Device for alcohol distillation decoloring and purification and method for purification in maltol production | |
| CN112500933A (en) | Process for purification of crude fatty acids | |
| CN105037473B (en) | A kind of method of the purification sterol from tall oil | |
| CN106496026A (en) | In the method that acer truncatum buge oil prepares neural acetoacetic ester as raw material | |
| CN111072469B (en) | Method for extracting natural nervonic acid | |
| US2361411A (en) | Distillation of fatty acids | |
| CN107722093B (en) | Process for extracting sterol from vegetable oil deodorizer distillate | |
| CN105037133A (en) | Method of extracting nervonic acid from malania oleifera | |
| CN104151273B (en) | Device and the technique of furfural is extracted from paper waste | |
| CN110734365A (en) | method for recovering acetone waste liquid in cephalosporin synthesis | |
| TW202000875A (en) | Method for extracting sesame lignans from by-product generated from production of sesame oil capable of extracting sesame lignans from a by-product containing a relatively low amount, such as 1.5 weight%, of sesame lignans | |
| CN110386877B (en) | Separation method of hydrolysis mixture | |
| CN217459358U (en) | High-purity fatty acid preparation facilities | |
| CN115650943B (en) | Method for enriching polyunsaturated fatty acid ester, squalene, natural vitamin E and phytosterol from plant deodorization distillate | |
| CN111848385B (en) | Extraction method of itaconic acid in fermentation process itaconic acid mother liquor | |
| CN102746148A (en) | Method for purifying dimethyl succinate | |
| CN117486712A (en) | Flash separation process of m-methylbenzoic acid |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| RJ01 | Rejection of invention patent application after publication | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20210316 |