Refining method of non-petroleum-based ethylene glycol
阅读说明：本技术 一种非石油基乙二醇的精制方法 (Refining method of non-petroleum-based ethylene glycol ) 是由 袁一 于 2018-09-05 设计创作，主要内容包括：本发明提供了一种精制非石油基乙二醇的方法,其中分离了与乙二醇沸点接近的杂质。在该方法中,将C<Sub>5</Sub>-C<Sub>20</Sub>亲油醇类化合物,C<Sub>5</Sub>-C<Sub>20</Sub>烷烃和/或C<Sub>4</Sub>-C<Sub>20</Sub>亲油酮类化合物作为共沸剂与非石油基乙二醇进行共沸得到包含乙二醇的共沸物,然后将该共沸物中的共沸剂分离除去获得乙二醇粗品,该乙二醇粗品进一步纯化后获得乙二醇。(The present invention provides a process for the purification of non-petroleum based glycols in which impurities having boiling points close to that of the glycol are separated. In the method, C is 5 ‑C 20 Lipophilic alcohol compounds, C 5 ‑C 20 Alkane and/or C 4 ‑C 20 And (3) taking the oleophylic ketone compound as an entrainer to perform azeotropy with non-petroleum glycol to obtain an azeotrope containing glycol, separating and removing the entrainer in the azeotrope to obtain a crude product of the glycol, and further purifying the crude product of the glycol to obtain the glycol.)
1. A process for the purification of non-petroleum based glycols wherein C is5-C20Lipophilic alcohol compounds, C5-C20Alkane and C4-C20One or more of oleophylic ketone compounds are used as an entrainer to carry out azeotropy with the non-petroleum-based glycol to obtain an azeotrope containing glycol, then water is added to dissolve the glycol in the azeotrope, the entrainer which is insoluble in water is separated from the glycol aqueous solution, and the glycol aqueous solution is dehydrated and refined to obtain the glycol.
2. The method according to claim 1, wherein said C5-C20The lipophilic alcohol compound is C6-C15Lipophilic alcohol compounds, preferably C7-C12Lipophilic alcohol compounds, particularly preferably C7-C10Lipophilic alcohol compounds, and the lipophilic alcohol compounds may be aliphatic alcohols and heterocyclic ring-containing alcohols such as pentanol and its isomers, hexanol and its isomers, heptanol and its isomers, octanol and its isomers, nonanol and its isomers, decanol and its isomers, undecanol and its isomers, lauryl alcohol and its isomers and benzyl alcohol.
3. The method according to claim 2, wherein said C5-C20The lipophilic alcohol compounds are hexanol, isohexanol, heptanol, isoheptanol, octanol, isooctanol, nonanol, isononanol, decanol and isodecanol.
4. A method according to any one of claims 1 to 3, wherein C is5-C20The alkane is C5-C15Alkanes, preferably C5-C12Alkanes, particularly preferably C5-C10The alkane may be a linear alkane, branched alkane, cycloalkane or benzene ring-containing alkane, such as pentane and its isomers, hexane and its isomers, heptane and its isomers, octane and its isomers, nonane and its isomers, decane and its isomers, undecane and its isomers, dodecane and its isomers, cyclopentane, cyclohexane, ethylbenzene and its isomers, preferably hexane, heptane, octane, nonane, decane, undecane, dodecane, cyclopentane, cyclohexane, ethylbenzene and its isomers.
5. A method according to any one of claims 1 to 4, wherein C is4-C20The lipophilic ketone compound is C5-C15Lipophilic ketone compounds, preferably C6-C12Lipophilic ketones, particularly preferably C6-C10Lipophilic ketone compounds, and the ketone may be aliphatic or alicyclicKetones, preferably heptanone, diisobutyl ketone, cyclohexanone, 2-nonanone.
6. The method according to any one of claims 1 to 5, wherein the non-petroleum based glycol is coal-derived glycol or glycol derived from biomass, wherein the biomass preferably refers to non-food second generation biomass including edible first generation biomass such as corn, sugar cane and the like and agroforestry waste such as straw, wood, bagasse and the like.
7. The process according to any one of claims 1-6, wherein the non-petroleum based glycol comprises, but is not limited to, ethylene glycol, butanediol (preferably 1, 2-butanediol), pentanediol (preferably 1, 2-pentanediol), and hexanediol (preferably 1, 2-hexanediol), preferably further comprising。
8. The process according to any one of claims 1-7, wherein the non-petroleum based glycol comprises propylene glycol, propylene triol and/or sorbitol.
9. The process according to any one of claims 1-8, wherein the non-petroleum based glycol comprises
1 to 100% by weight of ethylene glycol, with the exception of the 100% by weight endpoint, preferably 1 to 99% by weight of ethylene glycol, more preferably 5 to 99% by weight of ethylene glycol, particularly preferably 10 to 95% by weight of ethylene glycol,
from 0 to 95% by weight, preferably from 0 to 50% by weight, more preferably from 0 to 30% by weight, particularly preferably from 0 to 10% by weight, of butanediol, preferably 1, 2-butanediol, with the exception of the endpoint 0,
0 to 95% by weight, preferably 0 to 50% by weight, more preferably 0 to 10% by weight, particularly preferably 0 to 1% by weight, of pentanediol, preferably 1, 2-pentanediol, with the exception of the endpoint 0,
0 to 95% by weight, preferably 0 to 50% by weight, more preferably 0 to 10% by weight, particularly preferably 0 to 1% by weight, of hexanediol, preferably 1, 2-hexanediol, with the exception of the endpoint 0, and
optionally 0 to 95 weight percent%, preferably 0 to 50% by weight, more preferably 0 to 10% by weight, particularly preferably 0 to 1% by weight
10. The process according to any one of claims 1-9, wherein the non-petroleum based glycol comprises
0 to 95% by weight, preferably 0.1 to 50% by weight, of 1, 2-propanediol,
0 to 50 wt.%, preferably 0.01 to 10 wt.%, of 2, 3-butanediol,
0 to 20% by weight, preferably 0.01 to 10% by weight, of glycerol, and/or
0 to 20% by weight, preferably 0.01 to 10% by weight, of sorbitol.
11. The process according to any one of claims 1 to 10, wherein the non-petroleum based glycol comprises minor amounts of acids, ethers, aldehydes, ketones and/or alcohols as impurities affecting the uv transmittance of the glycol, even below the detection limit of gas chromatography.
Technical Field
The invention relates to a method for refining ethylene glycol, in particular to a method for refining ethylene glycol, which comprises butanediol, pentanediol, hexanediol and optional components
Background
In recent years, due to uncertainty in oil prices and the attention paid to sustainable development, non-petroleum routes such as coal-to-ethylene glycol and the production of ethylene glycol from biomass have been rapidly developed. However, made ofThe differences in the synthetic routes result in the non-petroleum route to ethylene glycol producing by-products such as butanediol, pentanediol, hexanediol, and ethylene glycol that are different from those produced by petroleum routes,
US4935102, US4966658, US5423955, US8906205 all describe techniques for separating ethylene glycol from butanediol using different azeotroping agents. The azeotropic agent and the glycol have an azeotropic point. The temperature of the azeotropic point is generally significantly lower than the boiling point of ethylene glycol. Thus, the boiling point of the azeotrope of the ethylene glycol and the entrainer and the boiling point of impurities such as butanediol generate obvious temperature difference, and the separation of the ethylene glycol and the butanediol can be economically achieved through a rectification mode.
Processes for the production of ethylene glycol by non-petroleum routes produce other products besides butanediol such as pentanediol, hexanediol, and ethylene glycol,
CN106946654A describes a method for purifying ethylene glycol by adsorbing impurities in biomass ethylene glycol with an adsorption bed filled with porous carbon adsorbent. This technique only describes the enhancement of the uv transmittance of ethylene glycol and does not teach the ability to separate butanediol, a compound of the formula:
Disclosure of Invention
The present invention provides a process for the purification of non-petroleum based glycols in which impurities having boiling points close to that of the glycol are separated. The method can improve the purity of the ethylene glycol to more than 99.90%, preferably more than 99.95%, under the condition of high yield of more than 95%, preferably more than 97%, particularly preferably more than 98%, and the ultraviolet transmittance of the obtained ethylene glycol at the wavelengths of 220nm, 275nm and 350nm to more than 75%, 92% and 99% respectively.
By non-petroleum based ethylene glycol is meant ethylene glycol produced by non-petroleum routes, particularly coal derived ethylene glycol or ethylene glycol derived from biomass, including but not limited to ethylene glycol, butylene glycol, pentylene glycol and hexylene glycol. Preferably, the non-petroleum based glycol further comprises a compound having the formula:
In the process of the invention, C is5-C20Lipophilic alcohol compounds, C5-C20Alkane and C4-C20One or more of oleophylic ketone compounds are used as an entrainer to carry out azeotropy with the non-petroleum-based glycol to obtain an azeotrope containing glycol, then water is added to dissolve the glycol in the azeotrope, the entrainer which is insoluble in water is separated from the glycol aqueous solution, and the glycol aqueous solution is dehydrated and refined to obtain the glycol.
In one embodiment of the invention, said C5-C20The lipophilic alcohol compound is preferably C6-C15Lipophilic alcohol compound, more preferably C7-C12Lipophilic alcohol compounds, particularly preferably C7-C10A lipophilic alcohol compound. The lipophilic alcohol compound can be fatty alcohol and alcohol containing heterocycle. Examples of such lipophilic alcohol compounds are e.g. pentanol and its isomers, hexanol and its isomers, heptanol and its isomers, octanol and its isomers, nonanol and its isomers, decanol and its isomers, undecanol and its isomers, lauryl alcohol and its isomers and benzyl alcohol. Very preferably, the lipophilic alcohol compounds are heptanol, isoheptanol, octanol, isooctanol, nonanol, isononanol, decanol and isodecanol.
In another embodiment of the present invention, said C5-C20The alkane is preferably C5-C15Alkanes, preferably C5-C12Alkanes, particularly preferably C5-C10An alkane. The alkane may be straight-chain alkane, branched-chain alkane, cycloalkane or benzene ring-containing alkane. Examples of such alkanes are pentane and its isomers, hexane and its isomers, heptane and its isomers, octane and its isomers, nonane and its isomers, decane and its isomers, undecane and its isomers, dodecane and its isomers, cyclopentane and cyclohexane, ethylbenzene and its isomers. It is very much preferred that,the alkane is hexane, heptane, octane, nonane, decane, undecane, dodecane, cyclopentane, cyclohexane, ethylbenzene.
In another embodiment of the present invention, said C4-C20The oleophilic ketone compound is preferably C5-C15Lipophilic ketone compound, more preferably C6-C12Lipophilic ketones, particularly preferably C6-C10Lipophilic ketone compounds. The ketone may be an aliphatic or alicyclic ketone. Very preferably, the ketone is heptanone, diisobutyl ketone, cyclohexanone, 2-nonanone.
The biomass in the invention preferably refers to the first generation of edible biomass such as corn, sugarcane and the like, and the second generation of non-grain biomass of agricultural and forestry wastes such as straw, wood, bagasse and the like. Preferably, the non-petroleum based glycols of the present invention include, but are not limited to, ethylene glycol, butanediol (preferably 1, 2-butanediol), pentanediol (preferably 1, 2-pentanediol), hexanediol (preferably 1, 2-hexanediol), and
1 to 100% by weight of ethylene glycol (excluding the 100% by weight endpoint), preferably 1 to 99% by weight of ethylene glycol, more preferably 5 to 99% by weight of ethylene glycol, particularly preferably 10 to 95% by weight of ethylene glycol,
from 0 to 95% by weight, preferably from 0 to 50% by weight, more preferably from 0 to 30% by weight, particularly preferably from 0 to 10% by weight, of butanediol (preferably 1, 2-butanediol; with the exception of endpoint 0),
0 to 95% by weight, preferably 0 to 50% by weight, more preferably 0 to 10% by weight, particularly preferably 0 to 1% by weight, of pentanediol (preferably 1, 2-pentanediol; with the exception of endpoint 0),
0 to 95% by weight, preferably 0 to 50% by weight, more preferably 0 to 10% by weight, particularly preferably 0 to 1% by weight, of hexanediol (preferably 1, 2-hexanediol; with the exception of endpoint 0), and
optionally from 0 to 95% by weight, preferably 0-50% by weight, more preferably 0 to 10% by weight, particularly preferably 0 to 1% by weight of。
The non-petroleum based glycol further optionally comprises:
0 to 95% by weight, preferably 0.1 to 50% by weight, of 1, 2-propanediol,
0 to 50 wt.%, preferably 0.01 to 10 wt.%, of 2, 3-butanediol,
0 to 20% by weight, preferably 0.01 to 10% by weight, of glycerol, and/or
0 to 20% by weight, preferably 0.01 to 10% by weight, of sorbitol.
In the process of the invention, the entrainer azeotropes with ethylene glycol to form an azeotrope. The boiling point of the azeotrope is related to impurities such as butanediol, pentanediol, hexanediol, hexane diol,
The azeotropic agent can be separated from the aqueous solution containing ethylene glycol by an extraction process after the azeotrope is mixed with water. The aqueous solution containing ethylene glycol is dehydrated and then purified to obtain ethylene glycol.
Drawings
FIG. 1 is a flow diagram of the azeotropic refining of non-petroleum based ethylene glycol of the present invention.
FIG. 2 is a flow diagram of a conventional rectification process for non-petroleum based glycols.
Detailed Description
The refining process of the present invention is described below with reference to FIG. 1:
the mixed alcohol feed and the entrainer feed are mixed and then enter an azeotropic tower, wherein the azeotropic tower is a rectifying tower. The weight percentage of the ethylene glycol in the entrainer feed and the mixed alcohol feed is 0.1: 1-20: 1, preferably 0.2: 1-10: 1, and more preferably 0.5: 1-10: 1. The operating pressure of the azeotropic column is 1 kPa (absolute) to 101 kPa (absolute)) And the weight ratio (namely, reflux ratio) of the reflux material to the extraction material of the azeotropic tower is 0.1: 1-15: 1. Wherein a majority of the ethylene glycol and a small amount of other impurities in the mixed alcohol feed are withdrawn from the top of the azeotropic column (i.e., stream 1) along with the entrainer and enter the top phase separator. Including but not limited to butanediol, pentanediol, hexanediol, and optionally
Stream 1 is mixed with fresh water and optionally recycled water (i.e., stream 4) in an overhead phase separator and the layers are separated. Recycling the entrainer layer (namely, the material flow 2) to the azeotropic tower; while the aqueous layer (i.e., stream 3) enters the overhead dehydration column.
In the overhead dehydration column, water in stream 3 is taken overhead (i.e., stream 4) and recycled to the overhead phase separator. The ethylene glycol containing light component impurities (i.e., stream 5) is withdrawn at a side stream and enters an ethylene glycol refining column. The heavies impurities in the column bottoms (i.e., stream 6) exit the system.
Stream 5 is refined and purified ethylene glycol in an ethylene glycol refining column, which is taken off the side line of the refining column. The purity and ultraviolet transmittance of the obtained glycol product both meet the requirements of fiber-grade and bottle-grade polyester. Other light component impurities are extracted from the top of the ethylene glycol refining tower. Heavy component impurities are extracted from the tower kettle of the ethylene glycol refining tower.
The azeotrope column bottoms (i.e., stream 8) enters the evaporator where the very high boiling heavy component impurities, such as glycerol and sorbitol, are separated from the evaporator bottom and exit the system (i.e., stream 9).
Including but not limited to entrainers, butanediol, pentanediol, hexanediol, and optionally
The water in the water layer of the kettle phase separator (i.e., stream 12) is separated in the kettle dehydration column and taken overhead (i.e., stream 13) and recycled to the kettle phase separator. While impurities including, but not limited to, butanediol, pentanediol and hexanediol are withdrawn from the bottom of the dehydration column and vented out of the system.
The technology of the invention can react the glycol in the non-petroleum glycol with butanediol, pentanediol, hexanediol and optional butanediol, hexanediol and optionally ethanol under the condition of high glycol recovery rate of more than 95%, preferably more than 97%, and particularly preferably more than 98%
