CN114790188A - Refining and purifying method of crude glycolide - Google Patents
Refining and purifying method of crude glycolide Download PDFInfo
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- RKDVKSZUMVYZHH-UHFFFAOYSA-N 1,4-dioxane-2,5-dione Chemical compound O=C1COC(=O)CO1 RKDVKSZUMVYZHH-UHFFFAOYSA-N 0.000 title claims abstract description 100
- 238000007670 refining Methods 0.000 title claims abstract description 41
- 238000000034 method Methods 0.000 title claims abstract description 28
- 239000003513 alkali Substances 0.000 claims abstract description 70
- 239000007788 liquid Substances 0.000 claims abstract description 69
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims abstract description 64
- 239000003153 chemical reaction reagent Substances 0.000 claims abstract description 48
- 238000005406 washing Methods 0.000 claims abstract description 46
- 238000000746 purification Methods 0.000 claims abstract description 9
- 238000001704 evaporation Methods 0.000 claims abstract description 7
- 230000008020 evaporation Effects 0.000 claims abstract description 7
- 239000000203 mixture Substances 0.000 claims abstract description 4
- AEMRFAOFKBGASW-UHFFFAOYSA-N Glycolic acid Chemical compound OCC(O)=O AEMRFAOFKBGASW-UHFFFAOYSA-N 0.000 claims description 31
- 239000012535 impurity Substances 0.000 claims description 20
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 claims description 15
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 claims description 13
- 239000003795 chemical substances by application Substances 0.000 claims description 11
- 238000000926 separation method Methods 0.000 claims description 9
- 229910052783 alkali metal Inorganic materials 0.000 claims description 6
- 150000001340 alkali metals Chemical class 0.000 claims description 6
- BVKZGUZCCUSVTD-UHFFFAOYSA-M Bicarbonate Chemical class OC([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-M 0.000 claims description 3
- 150000004649 carbonic acid derivatives Chemical class 0.000 claims 1
- 238000007701 flash-distillation Methods 0.000 claims 1
- 239000002699 waste material Substances 0.000 abstract description 6
- 238000002156 mixing Methods 0.000 abstract description 4
- 239000002904 solvent Substances 0.000 abstract description 2
- 239000012467 final product Substances 0.000 description 14
- 239000000047 product Substances 0.000 description 12
- 238000003756 stirring Methods 0.000 description 11
- 238000002844 melting Methods 0.000 description 8
- 230000008018 melting Effects 0.000 description 8
- 230000008569 process Effects 0.000 description 7
- 230000000052 comparative effect Effects 0.000 description 6
- 229920000954 Polyglycolide Polymers 0.000 description 5
- 239000002585 base Substances 0.000 description 5
- 238000005265 energy consumption Methods 0.000 description 5
- 230000005484 gravity Effects 0.000 description 5
- 239000004633 polyglycolic acid Substances 0.000 description 4
- 238000006116 polymerization reaction Methods 0.000 description 4
- 239000002253 acid Substances 0.000 description 3
- 150000002148 esters Chemical class 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 230000014759 maintenance of location Effects 0.000 description 3
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 2
- 239000003054 catalyst Substances 0.000 description 2
- 229920001577 copolymer Polymers 0.000 description 2
- 238000002425 crystallisation Methods 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 2
- 239000003344 environmental pollutant Substances 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 231100000719 pollutant Toxicity 0.000 description 2
- 238000011084 recovery Methods 0.000 description 2
- 238000001953 recrystallisation Methods 0.000 description 2
- 150000003839 salts Chemical class 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- TXUICONDJPYNPY-UHFFFAOYSA-N (1,10,13-trimethyl-3-oxo-4,5,6,7,8,9,11,12,14,15,16,17-dodecahydrocyclopenta[a]phenanthren-17-yl) heptanoate Chemical compound C1CC2CC(=O)C=C(C)C2(C)C2C1C1CCC(OC(=O)CCCCCC)C1(C)CC2 TXUICONDJPYNPY-UHFFFAOYSA-N 0.000 description 1
- 229910021626 Tin(II) chloride Inorganic materials 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000012620 biological material Substances 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 230000008025 crystallization Effects 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 230000018044 dehydration Effects 0.000 description 1
- 238000006297 dehydration reaction Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 239000011552 falling film Substances 0.000 description 1
- 230000007062 hydrolysis Effects 0.000 description 1
- 238000006460 hydrolysis reaction Methods 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- 239000011259 mixed solution Substances 0.000 description 1
- 150000002894 organic compounds Chemical class 0.000 description 1
- 239000003960 organic solvent Substances 0.000 description 1
- 238000000197 pyrolysis Methods 0.000 description 1
- 230000008929 regeneration Effects 0.000 description 1
- 238000011069 regeneration method Methods 0.000 description 1
- 238000007151 ring opening polymerisation reaction Methods 0.000 description 1
- 235000011150 stannous chloride Nutrition 0.000 description 1
- 239000001119 stannous chloride Substances 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D319/00—Heterocyclic compounds containing six-membered rings having two oxygen atoms as the only ring hetero atoms
- C07D319/10—1,4-Dioxanes; Hydrogenated 1,4-dioxanes
- C07D319/12—1,4-Dioxanes; Hydrogenated 1,4-dioxanes not condensed with other rings
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Heterocyclic Compounds That Contain Two Or More Ring Oxygen Atoms (AREA)
Abstract
The invention relates to a refining and purifying method of crude glycolide, which comprises the steps of fully mixing liquid crude glycolide from a glycolide depolymerization device with an alcohol reagent, then washing with alcohol, then sending the mixture into a liquid-liquid separator to obtain purified glycolide liquid, and then carrying out alkali reagent washing refining and reduced pressure flash evaporation on the obtained purified glycolide liquid to obtain refined glycolide, thus finishing the refining and purification. Compared with the prior art, the washing solvent alcohol can be recycled, only a small amount of alkali-containing waste liquid is generated, the purification period is short, the continuous operation can be realized, the yield of glycolide can be ensured to be more than 80%, the purity is more than 99.5%, and the method is suitable for industrial large-scale application.
Description
Technical Field
The invention belongs to the technical field of chemical separation and purification, and relates to a refining and purifying method of crude glycolide.
Background
Glycolide is an important organic compound which can be used for preparing polyglycolic acid and copolymers thereof, and is a few biological materials which can be used for clinic due to good biocompatibility and biodegradability of the polyglycolic acid and the copolymers thereof, so that the glycolide is of great interest.
High molecular weight polyglycolide needs high purity glycolide to be synthesized as an intermediate, glycolide is synthesized by pyrolysis of a glycolic acid oligomer in the presence of a catalyst, and the synthesized product contains impurities such as water, glycolic acid oligomer and the like, and the mixed product is called as "crude glycolide". The presence of impurities adversely affects the ring-opening polymerization of glycolide, water therein causes hydrolysis of glycolide to glycolic acid and also hydrolyzes and breaks the chain of polyglycolic acid, and the glycolic acid and glycolic acid oligomer contained therein are acidic and cause acidolysis and degradation of polyglycolic acid, so that the crude glycolide must be purified to remove impurities therefrom to a certain purity.
The commonly used methods for refining crude glycolide include recrystallization, rectification, and melt crystallization. Recrystallization methods (such as patents CN105218512B and CN110511205B) require the use of organic solvents to wash and purify crude glycolide products for many times, which not only has long purification period, but also causes great problems of solvent regeneration energy consumption and environmental pollution. The purification by the rectification method (CN106928180B, CN 104619690B) utilizes the volatility difference among various substances in a crude glycolide product, and the boiling point difference of components in the crude glycolide is small, so that the problems of high tower equipment cost, high separation energy consumption and the like are caused. The high-purity glycolide products can be obtained by a melting crystallization method (such as patents CN111548339A and CN 107304196A), but the operation period is long, the requirement on the operation precision of equipment is high, and higher energy consumption can be generated by continuously increasing and reducing the temperature.
Disclosure of Invention
The invention aims to provide a refining and purifying method of crude glycolide, which can realize continuous operation, has little pollution, low cost and short operation period, and can ensure that the yield of the glycolide is more than 80 percent and the purity is more than 99.5 percent.
The purpose of the invention can be realized by the following technical scheme:
a process for refining and purifying coarse glycolide includes such steps as mixing the liquid coarse glycolide from the depolymerization unit of glycolide with alcohol reagent, washing with alcohol, liquid-liquid separation to obtain purified glycolide liquid, alkali reagent washing and flash evaporation under reduced pressure to obtain refined glycolide.
Further, the alcohol reagent is one or more of methanol, ethanol and isopropanol.
Further, the mass ratio of the liquid crude glycolide to the alcohol reagent is 1: (0.5-1).
Further, the pressure in the alcohol washing process is 150-500kpa, the temperature is 83-100 ℃, and the washing time is 20-60 min.
Further, the liquid-liquid separator is a centrifugal separator or a liquid separation tank.
Further, the alkali reagent used in the alkali reagent washing and refining is one or more of alkali metal, alkali of alkali metal, carbonate and bicarbonate.
Further, the amount of the alkali agent added is 1 to 2 times the total molar amount of impurities including glycolic acid and glycolic acid oligomer in the purified glycolide liquid.
Further, the pressure of the alkali reagent for washing and refining is normal pressure, the temperature is 83-100 ℃, and the washing and refining time is 10-20 min.
Further, the temperature of the reduced pressure flash evaporation is 110-130 ℃, and the pressure is 5-10 Kpa.
Furthermore, the times of washing and refining by the alcohol and the alkali agent are respectively and independently one or more times.
Compared with the prior art, the invention has the following advantages:
(1) the washing process is a liquid-liquid mixed contact process, and the media can achieve molecular-level contact, so the washing efficiency is high, the washing times can be reduced, the glycolide loss is less, the recovery rate is high, and the overall refining time is short;
(2) after the alcohol reagent is washed, the alcohol reagent can be recycled, the amount of alkali reagent added in the refining process is very small, and serious salt-containing waste liquid pollution cannot be caused;
(3) the temperature is not frequently increased and decreased in the operation process, so that the energy consumption is low, the continuous operation can be realized, the total retention time in the purification process is reduced, and the deterioration of glycolide is less;
(4) the equipment with high cost and high operation precision requirements such as a rectifying tower, a falling film crystallizer and the like is not used, so that the cost is low; the device has simple structure and safe operation, and can realize the large-scale and continuous industrial production of glycolide.
Drawings
FIG. 1 is a schematic flow diagram of the present invention;
the notation in the figure is:
a 1-alcohol scrubber; 2-a liquid-liquid separator; 3-an alkaline scrubber; 4-reduced pressure flash evaporator;
s1-crude glycolide product from the depolymerization unit; s2-alcohol reagent; s3-alcohol/crude ester mixture; s4-purifying the glycolide liquid; s5-containing acid washing liquid; s6-base reagent; s7-washing glycolide liquid with alkali; s8-refined glycolide; s9-salt-containing waste liquid.
Detailed Description
The invention is described in detail below with reference to the figures and the specific embodiments. The present embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation manner and a specific operation process are given, but the scope of the present invention is not limited to the following embodiments.
The purification process of the present invention will be described below:
the invention provides a refining and purifying method of crude glycolide, which comprises the steps of fully mixing liquid crude glycolide from a glycolide depolymerization device with an alcohol reagent, washing with alcohol, sending the mixture into a liquid-liquid separator to obtain purified glycolide liquid, washing and refining the purified glycolide liquid with an alkali reagent, and carrying out reduced pressure flash evaporation to obtain refined glycolide, thus finishing refining and purifying.
In some embodiments, the alcohol reagent is one or more of methanol, ethanol, and isopropanol.
In some embodiments, the mass ratio of the liquid crude glycolide to the alcohol reagent is 1: (0.5-1), and under the proportion, the three aspects of impurity removal effect, glycolide yield and alcohol recovery energy consumption achieve better coupling.
In some embodiments, the pressure during the alcohol wash is 150-.
In some embodiments, the liquid-liquid separator is a centrifuge or a separation tank.
In some embodiments, the alkali agent used in the alkali agent washing and refining is one or more of alkali metal, alkali metal base, carbonate and bicarbonate.
Further, the amount of the alkali agent added is 1 to 2 times the total molar amount of impurities including glycolic acid and glycolic acid oligomers in the purified glycolide liquid.
In some embodiments, the pressure of the alkali agent washing refining is normal pressure, the temperature is 83-100 ℃, and the washing refining time is 10-20 min.
In some embodiments, the temperature of the reduced pressure flash is 110-130 ℃ and the pressure is 5-10 Kpa.
In some embodiments, the number of alcohol washes and alkaline agent washes is independently one or more.
Specifically, referring to fig. 1, the process flow of the present invention comprises the following steps: 1) mixing a crude glycolide product S1 from a depolymerization device and an alcohol reagent S2 in an alcohol washer 1 under the low pressure of 150-500kpa, fully stirring, controlling the mass ratio of alcohol to crude ester in the process to be 0.5-1, the washing temperature to be 83-100 ℃, and the retention time of the washing mixed liquid to be 20-60 min; 2) performing liquid-liquid separation on the alcohol/crude ester mixed solution S3 by using a liquid-liquid separator 2 such as a gravity liquid separation tank or a centrifuge to obtain purified glycolide liquid S4 and acid-containing washing liquid S5; 3) after liquid-liquid separation, discharging acid-containing washing liquid S5, adding an alkali reagent S6 into the purified glycolide liquid S4, and fully stirring in an alkali scrubber 3 at normal pressure to obtain alkali-washed glycolide liquid S7, wherein the washing temperature is 83-100 ℃, the retention time of the mixed liquid is 10-20min, and the adding amount of the alkali reagent S6 is controlled to be 1-2 times of the total molar amount of glycolic acid and glycolic acid oligomer impurities in the purified glycolide liquid S4; 4) and (3) sending the alkali washed glycolide liquid S7 into a reduced pressure flash evaporator 4 for reduced pressure flash evaporation to obtain refined glycolide, wherein the temperature of the reduced pressure flash evaporation is controlled to be 110-130 ℃, and the pressure is 5-10 kpa.
The above embodiments may be implemented individually, or in any two or more combinations.
The above embodiments will be described in more detail with reference to specific examples.
Example 1
Synthesis of crude glycolide: adding 3kg of 70 percent (mass fraction) glycolic acid aqueous solution and 8g of stannous chloride catalyst into a 5L reaction vessel, stirring under normal pressure, heating the solution to 190 ℃ for dehydration, then reducing the system pressure to 8kpa, further dehydrating for 150min to prepare glycolic acid oligomer, then heating to about 250 ℃, and reducing the pressure to 1kpa for oligomer depolymerization to obtain 1650g of crude glycolide.
Example 2
Melting 100g of crude glycolide synthesized in example 1, placing in an alcohol scrubber, adding 90g of methanol, controlling the temperature and pressure at 100 ℃ and 500kpa respectively, stirring for 30min, separating in a gravity liquid-liquid separator to obtain purified glycolide liquid, and placing the purified glycolide liquid in an alkali scrubber to obtain CaCO 3 The molar weight of the added alkali is 1.2 times of that of impurities, the pressure for washing and refining the alkali reagent is normal pressure, the temperature is 85 ℃, the alkali reagent enters a reduced pressure flash evaporator after being washed for 20min, the temperature is raised to 110 ℃, the pressure is reduced to 10kpa, the yield of the final product is 82.6%, and the purity is 99.5%.
Example 3
Melting 100g of crude glycolide synthesized in example 1, placing into an alcohol scrubber, adding 80g of ethanol, controlling the temperature and pressure at 100 ℃ and 450kpa respectively, stirring for 40min, separating in a gravity liquid-liquid separator to obtain purified glycolide liquid, and placing the purified glycolide liquid into an alkali scrubber, wherein the alkali is NaHCO 3 The molar weight of the added alkali is 1.4 times of that of impurities, the pressure for washing and refining the alkali reagent is normal pressure, the temperature is 100 ℃, the alkali reagent enters a reduced pressure flash evaporator after being washed for 20min, the temperature is raised to 115 ℃, the pressure is reduced to 8kpa, the yield of the final product is 83.3%, and the purity is 99.6%.
Example 4
100g of the crude glycolide synthesized in example 1 was melted and placed in an alcohol scrubber, 70g of isopropyl alcohol was added,controlling temperature and pressure at 95 deg.C and 350kpa respectively, stirring for 45min, separating in centrifugal liquid-liquid separator, and washing with alkali (Na) in alkali scrubber to obtain purified glycolide liquid 2 CO 3 The molar weight of the added alkali is 1.6 times of that of impurities, the pressure for washing and refining the alkali reagent is normal pressure, the temperature is 90 ℃, the alkali reagent enters a reduced pressure flash evaporator after washing for 15min, the temperature is raised to 115 ℃, the pressure is reduced to 8kpa, the yield of the final product is 83.8%, and the purity is 99.7%.
Example 5
Melting 100g of crude glycolide synthesized in example 1, placing in an alcohol scrubber, adding 60g of isopropanol, controlling the temperature and pressure at 90 ℃ and 250kpa respectively, stirring for 50min, separating in a centrifugal liquid-liquid separator, and placing the obtained purified glycolide liquid in an alkaline scrubber, wherein the alkali is K 2 CO 3 The molar weight of the added alkali is 1.8 times of that of impurities, the pressure for washing and refining the alkali reagent is normal pressure and 85 ℃, the alkali reagent enters a reduced-pressure flash evaporator after being washed for 10min, the temperature is raised to 120 ℃, the pressure is reduced to 5kpa, the yield of the final product is 84.4%, and the purity is 99.8%.
Example 6
Melting 100g of crude glycolide synthesized in example 1, placing in an alcohol scrubber, adding 90g of ethanol, controlling temperature and pressure at 85 deg.C and 200kpa respectively, stirring for 30min, separating in a centrifugal liquid-liquid separator, and introducing the obtained purified glycolide liquid into an alkali scrubber with alkali of KHCO 3 The molar weight of the added alkali is 2 times of that of the impurities, the pressure of washing and refining the alkali reagent is normal pressure, the temperature is 83 ℃, the alkali reagent enters a reduced pressure flash evaporator after being washed for 10min, the temperature is raised to 125 ℃, the pressure is reduced to 5kpa, the yield of the final product is 83.1 percent, and the purity is 99.7 percent.
Example 7
Melting 100g of crude glycolide synthesized in example 1, placing into an alcohol scrubber, adding 80g of methanol, controlling temperature and pressure at 85 deg.C and 300kpa respectively, stirring for 45min, separating in a gravity liquid-liquid separator to obtain purified glycolide liquid, and placing the purified glycolide liquid into an alkali scrubber, wherein the alkali is MgCO 3 The molar weight of the added alkali is 1.8 times of that of the impurities, and the pressure for washing and refining the alkali reagent is normal pressure and temperatureWashing for 15min at 83 deg.C, entering into a reduced pressure flash evaporator, heating to 115 deg.C, and reducing pressure to 8kpa to obtain final product with yield of 83.0% and purity of 99.7%.
Example 8
Melting 100g of crude glycolide synthesized in example 1, placing in an alcohol scrubber, adding 70g of ethanol, controlling the temperature and pressure at 95 ℃ and 400kpa respectively, stirring for 50min, separating in a gravity liquid-liquid separator, and introducing the obtained purified glycolide liquid into an alkali scrubber with KHCO as alkali 3 The molar weight of the added alkali is 1.6 times of that of impurities, the pressure for washing and refining the alkali reagent is normal pressure, the temperature is 90 ℃, the alkali reagent enters a reduced pressure flash evaporator after being washed for 20min, the temperature is raised to 120 ℃, the pressure is reduced to 5kpa, the yield of the final product is 83.5%, and the purity is 99.9%.
Example 9
Melting 100g of crude glycolide synthesized in example 1, placing into an alcohol scrubber, adding 60g of isopropanol, controlling temperature and pressure at 83 deg.C and 200kpa respectively, stirring for 60min, separating in a centrifugal liquid-liquid separator to obtain purified glycolide liquid, and placing the purified glycolide liquid into an alkali scrubber with alkali Na as alkali 2 CO 3 The molar weight of the added alkali is 1.2 times of that of impurities, the pressure for washing and refining the alkali reagent is normal pressure and the temperature is 83 ℃, the alkali reagent enters a reduced pressure flash evaporator after being washed for 20min, the temperature is raised to 130 ℃, the pressure is reduced to 5kpa, the yield of a final product is 84.8%, and the purity is 99.5%.
Comparative example 1
100g of crude glycolide synthesized in example 1 was melted and placed in an alcohol scrubber under the same conditions and operating parameters as in example 2 except that the molar amount of the base added was 0.6 times the molar amount of the impurities, and the final product had a yield of 82.5% and a purity of 98.4%, which was comparable to example 2 but lower than example 2 and failed to meet the polymerization process requirements.
Comparative example 2
100g of crude glycolide synthesized in example 1 was melted and placed in an alcohol scrubber, and the conditions and operating parameters were the same as those in example 2 except that the molar amount of the base added was 2.2 times the molar amount of the impurities, and the final product yield was 82.3%, the purity was 98.4%, the yield was equivalent to that in example 2, but the purity was lower than that in example 2, and the requirements of the polymerization process were not met.
Comparative example 3
100g of crude glycolide synthesized in example 1 was melted and placed in an alcohol scrubber under the same conditions and operating parameters as in example 2 except that the molar amount of the base added was 0 times the molar amount of the impurities, and the final product had a yield of 82.6% and a purity of 95.5%, which was comparable to example 2 but lower than example 2 and failed to meet the polymerization process requirements.
Comparative example 4
100g of the crude glycolide synthesized in example 1 was melted and placed in a scrubber under the same conditions and operating parameters as in example 3 except that the amount of ethanol added was 120g, and the final product yield was 79.6%, the purity was 99.7%, and the product yield was significantly decreased.
Comparative example 5
100g of the crude glycolide synthesized in example 1 was melted and placed in a scrubber under the same conditions and operating parameters as in example 3 except that the amount of ethanol added was 40g, and the final product yield was 83.6%, the purity was 99.5%, and the amount of alkali-containing waste was 10.5g, which was 2.8 times that of example 3.
Comparative example 6
100g of the crude glycolide synthesized in example 1 was melted and placed in a scrubber under the same conditions and operating parameters as in example 3 except that the amount of ethanol added was 0g, and the final product yield was 83.9%, the purity was 99.7%, and the amount of alkali-containing waste liquid was 28.7g, which is 7.7 times that of example 3.
Through the comparison example, the purity of the product is reduced and the requirements of the subsequent polymerization process cannot be met when the amount of the alkali reagent is too small and too large after the same alcohol reagent is washed; when the ratio of the alkali reagent to the impurities is the same, the amount of the alcohol reagent is too large, the yield of the product is seriously reduced, and after the amount of the alcohol reagent is reduced, the amount of the waste liquid containing salt is greatly increased due to the increase of the amount of the alkali reagent, so that the pollutant treatment pressure is aggravated.
Therefore, the alcohol/alkali reagent washing method can keep the product purity at a higher level on the premise of ensuring the product yield, does not cause a great deal of pollutant treatment pressure, can realize continuous operation, and is beneficial to continuous and stable long-period operation of large-scale industrial devices.
The embodiments described above are described to facilitate an understanding and use of the invention by those skilled in the art. It will be readily apparent to those skilled in the art that various modifications to these embodiments may be made, and the generic principles described herein may be applied to other embodiments without the use of the inventive faculty. Therefore, the present invention is not limited to the above embodiments, and those skilled in the art should make improvements and modifications within the scope of the present invention based on the disclosure of the present invention.
Claims (10)
1. A refining and purifying method of crude glycolide is characterized in that liquid crude glycolide from a glycolide depolymerization device is fully mixed with an alcohol reagent and then subjected to alcohol washing, then the mixture is sent to a liquid-liquid separator to obtain purified glycolide liquid, and the obtained purified glycolide liquid is subjected to alkali reagent washing refining and reduced pressure flash evaporation to obtain refined glycolide, so that the refining and purification are completed.
2. The method for refining and purifying crude glycolide, according to claim 1, characterized in that the alcohol reagent is one or more of methanol, ethanol and isopropanol.
3. The method for refining and purifying crude glycolide according to claim 1, wherein the mass ratio of the liquid crude glycolide to the alcohol reagent is 1: (0.5-1).
4. The refining and purifying method of crude glycolide as claimed in claim 1, wherein the pressure during the alcohol washing process is 150-500kpa, the temperature is 83-100 ℃, and the washing time is 20-60 min.
5. The method for refining and purifying crude glycolide according to claim 1, wherein the liquid-liquid separator is a centrifuge or a liquid separation tank.
6. The method for refining and purifying crude glycolide, according to claim 1, characterized in that the alkali agent used in the washing and purification with alkali agent is one or more of alkali metals, alkalis of alkali metals, carbonates and bicarbonates.
7. The method for refining and purifying crude glycolide according to claim 1 or 6, wherein the amount of the alkali agent added is 1 to 2 times the total molar amount of impurities including glycolic acid and glycolic acid oligomers in the purified glycolide liquid.
8. The method for refining and purifying crude glycolide according to claim 1, wherein the pressure for washing and purifying with an alkali reagent is normal pressure, the temperature is 83-100 ℃, and the washing and purifying time is 10-20 min.
9. The method for refining and purifying crude glycolide, according to claim 1, characterized in that the temperature of the reduced pressure flash distillation is 110-130 ℃, and the pressure is 5-10 Kpa.
10. The method for refining and purifying crude glycolide according to claim 1, wherein the number of washing with alcohol and the number of washing with an alkali agent are independently one or more.
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| CN116283888A (en) * | 2022-08-30 | 2023-06-23 | 深圳市迈启生物材料有限公司 | Method for preparing glycolide in batches |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100999516A (en) * | 2006-01-12 | 2007-07-18 | 中南大学 | Purifying process of glycolide |
| CN101054371A (en) * | 2007-05-24 | 2007-10-17 | 复旦大学 | Preparation method for glycolide |
| CN103058983A (en) * | 2012-12-18 | 2013-04-24 | 中国纺织科学研究院 | Method for purifying glycolide |
| CN103664866A (en) * | 2012-09-05 | 2014-03-26 | 中国石油化工股份有限公司 | Method for purifying glycolide |
| CN107868074A (en) * | 2016-09-26 | 2018-04-03 | 中国石油化工股份有限公司 | The method of purification of glycolide |
| CN111087381A (en) * | 2018-10-23 | 2020-05-01 | 中国石油化工股份有限公司 | Refining treatment method of glycolide |
-
2021
- 2021-01-26 CN CN202110106709.XA patent/CN114790188A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100999516A (en) * | 2006-01-12 | 2007-07-18 | 中南大学 | Purifying process of glycolide |
| CN101054371A (en) * | 2007-05-24 | 2007-10-17 | 复旦大学 | Preparation method for glycolide |
| CN103664866A (en) * | 2012-09-05 | 2014-03-26 | 中国石油化工股份有限公司 | Method for purifying glycolide |
| CN103058983A (en) * | 2012-12-18 | 2013-04-24 | 中国纺织科学研究院 | Method for purifying glycolide |
| CN107868074A (en) * | 2016-09-26 | 2018-04-03 | 中国石油化工股份有限公司 | The method of purification of glycolide |
| CN111087381A (en) * | 2018-10-23 | 2020-05-01 | 中国石油化工股份有限公司 | Refining treatment method of glycolide |
Non-Patent Citations (1)
| Title |
|---|
| 李江英: "《现代中药制剂理论与实践》", 30 September 2016, 陕西科学技术出版社, pages: 26 * |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116283888A (en) * | 2022-08-30 | 2023-06-23 | 深圳市迈启生物材料有限公司 | Method for preparing glycolide in batches |
| CN116410177A (en) * | 2022-08-30 | 2023-07-11 | 深圳市迈启生物材料有限公司 | Preparation method of medical glycolide |
| CN116283888B (en) * | 2022-08-30 | 2024-01-30 | 深圳市迈启生物材料有限公司 | Method for preparing glycolide in batches |
| CN116410177B (en) * | 2022-08-30 | 2024-01-30 | 深圳市迈启生物材料有限公司 | Preparation method of medical glycolide |
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