CN100545159C - The manufacture method of alpha-hydroxy organic acid cyclic ester - Google Patents
The manufacture method of alpha-hydroxy organic acid cyclic ester Download PDFInfo
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- CN100545159C CN100545159C CNB2005101377415A CN200510137741A CN100545159C CN 100545159 C CN100545159 C CN 100545159C CN B2005101377415 A CNB2005101377415 A CN B2005101377415A CN 200510137741 A CN200510137741 A CN 200510137741A CN 100545159 C CN100545159 C CN 100545159C
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Abstract
A kind of manufacture method with following formula alpha-hydroxy organic acid cyclic ester: wherein, R
1With R
2Can be respectively hydrogen atom or contain the alkyl that carbon number is 1-6; Comprise alpha-hydroxy organic acid or the formed oligomer of its ester class, become under the temperature of alpha-hydroxy organic acid cyclic ester in decomposing oligomer effectively, handle the manufacture method that obtains aforementioned alpha-hydroxy organic acid cyclic ester with the hypergravity device.The present invention utilizes the hypergravity device that alpha-hydroxy organic acid or the formed oligomer of its ester class are dispersed into imperceptible particle, reduce the resistance that alpha-hydroxy organic acid cyclic ester breaks away from oligomer, to reach quick cracking of alpha-hydroxy organic acid cyclic ester and the high advantage of yield.
Description
Technical field
The present invention relates to the manufacture method of a kind of alpha-hydroxy organic acid cyclic ester class (cyclic ester of α-hydroxycarboxylic acid) compound, it utilizes the hypergravity device to handle the oligomer of alpha-hydroxy organic acid (α-hydroxycarboxylic acid) or its ester class, obtains the alpha-hydroxy organic acid cyclic ester of quick cracking and high yield.
Background technology
Alpha-hydroxy organic acid, for example: the polymkeric substance of lactic acid (Lactic acid is called for short LA) or its ester class, this polymkeric substance is poly(lactic acid) (polylactic acid is called for short PLA) or polyglycolic acid (polyglycolicacid is called for short PGA) and multipolymer thereof etc. for example, these polymkeric substance have the characteristic of Biodegradable, are main force's product of following environmentally-friendly plastic.The manufacturing of poly(lactic acid) can become lactic acid oligomer by lactic acid polymerizes, becomes the lactic acid cyclic ester through cracking, becomes polyphosphazene polymer lactic acid by the lactic acid cyclic esters compound polymerization again; Another manufacture method is to form polyphosphazene polymer lactic acid by the lactic acid direct polymerization.
The manufacture method of the intermediate reaction thing lactic acid cyclic ester of first kind of polymerization methods of above-mentioned poly(lactic acid) is that through being cracked into the lactic acid cyclic ester, its reaction formula is as follows again for lactic acid oligomer by the synthetic lactic acid oligomer of lactic acid elder generation pre-polymerization:
In above-mentioned cracking process, if lactic acid cyclic ester product can't be removed in lactic acid oligomer rapidly, then the lactic acid cyclic ester again can be again and the oligomer polymerization of lactic acid, to such an extent as to need the extremely long time can finish cracking; If cracking time lengthening, then low-molecular-weight lactic acid oligomer itself also can be polymerized and be the lactic acid oligomer of higher molecular weight.Description according to United States Patent (USP) 5319107, scission reaction adopts the method (back-biting reaction) of inventing a charge against, the end end number (terminated group) of rate of cleavage and polymkeric substance is directly proportional, the end end number lower molecular weight of high-molecular weight polymer is few, therefore also can cause rate of cleavage slack-off; Rate of cleavage is slack-off to mean that heat-up time is elongated, side reaction thing thereby increase, its result becomes big for the reactant viscosity, heat passes and is difficult for, long-time high-temperature heating, then can cause the lactic acid oligomer carbonization, and cause the optically active lactic acid oligomer racemization of tool, produce the not optically active meso-rac-Lactide of tool (meso-lactide) product after the cracking in long-time heating.In addition, long-time heating can make part oligomer or product resolve into carbonic acid gas, and all poor heating effects all make rate of cleavage and yield reduce, and causing can't the commercialization mass production.Therefore, in order to solve above-mentioned disappearance, be necessary to seek the manufacture method of a lactic acid cyclic ester that rate of cleavage is fast, yield is high.
Above-mentioned is that the method that obtains higher cyclic ester yield has two kinds: a kind of for reducing the concentration of lactic acid oligomer, make the lactic acid cyclic ester in detach procedure, reduce the chance of colliding with lactic acid oligomer, known technology is for example: No. the 4727163rd, United States Patent (USP), be to be that principal constituent and lactic acid monomer copolymerization are after cracking process with polyalcohol ether (polyetherglycol), in cracking process because the shared deal of polyalcohol ether is more, reach diluted lactic acid oligomer function indirectly, to reduce the chance that cyclic ester contacts with its oligomer, but the shortcoming of this method is to use polyalcohol ether can decompose under pyritous, causes the puzzlement on the purifying products; Reactive tank is occupied by a large amount of polyalcohol ethers in addition, will make that the conversion unit utilization ratio is low.Another obtains the lactic acid cyclic ester method of high yield for reducing thickness of liquid film, the cyclic ester that cracking is produced can hightail oligomer and separate, avoid lactic acid cyclic ester and lactic acid oligomer to continue polymerization, the use thin-film evaporator is arranged in known technology, under condition of high vacuum degree, carry out, can reduce thickness of liquid film, the cyclic ester that cracking is produced can hightail oligomer and separate, but its effect is unsatisfactory.In nearest technology No. 4835293, No. 5091544 patent of United States Patent (USP) for example, utilize gas auxiliary law (gas-assisted) technology, the lactic acid cyclic ester that the lactic acid oligomer cracking is produced separates rapidly.The gas auxiliary law is after a kind of inertia current-carrying gas is dispersed into microvesicle (disperse phase), lactic acid oligomer liquid (external phase) by Pintsch process, gas-liquid is contacted closely, transfer to the lactic acid cyclic ester in the current-carrying gas rapidly, take system out of and reach isolating purpose by current-carrying gas again, the gas-to-liquid contact area is big more, and separating effect is good more.In No. the 5091544th, United States Patent (USP) for reaching the purpose of sharp separation lactic acid cyclic ester, its current-carrying gas volumetric flow rate and oligomer volume flow ratio be (high solution-air volume flow ratio) up to 2750: 1, the characteristics of this technology make cyclic ester break away from oligomer for using a large amount of gases, but cyclic ester is separated in a large amount of gases, need complex apparatus; Use a large amount of current-carrying gas to enter reactive tank in addition and can reduce temperature in the groove, and cause overflow (flooding) easily, processing procedure control is difficult for.Current-carrying gas is dispersed into microvesicle in addition needs special equipment, otherwise micro bubble may be condensed into air pocket and lose its function, and this also increases the complicacy of processing procedure.
Summary of the invention
The object of the present invention is to provide a kind of manufacture method of alpha-hydroxy organic acid cyclic ester.
For achieving the above object, the manufacture method with alpha-hydroxy organic acid cyclic ester of following formula provided by the invention:
Wherein, R
1With R
2Can be respectively hydrogen atom or contain the alkyl that carbon number is 1-6;
It becomes alpha-hydroxy organic acid or the formed oligomer of its ester class under the temperature of alpha-hydroxy organic acid cyclic ester in decomposing oligomer effectively, handles obtaining aforementioned alpha-hydroxy organic acid cyclic ester with the hypergravity device.
Described manufacture method, the temperature of wherein decomposing oligomer effectively and become alpha-hydroxy organic acid cyclic ester is 150-350 ℃.
Described manufacture method, wherein the chemical formula of alpha-hydroxy organic acid is HOCR
1R
2COOH, and R
1, R
2Can be respectively hydrogen atom or contain the alkyl that carbon number is 1-6.
Described manufacture method, wherein alpha-hydroxy organic acid is a lactic acid.
Described manufacture method, wherein alpha-hydroxy organic acid cyclic ester is a rac-Lactide.
Described manufacture method, wherein the hypergravity device has a high speed rotating mechanism.
Described manufacture method, wherein the high speed rotating mechanism of hypergravity device has a cellular structure.
Described manufacture method, wherein the hypergravity device imports current-carrying gas.
Described manufacture method, wherein current-carrying gas is a rare gas element.
Described manufacture method, wherein the hypergravity device is to carry out under vacuum state.
The present invention utilizes the hypergravity device that alpha-hydroxy organic acid or the formed oligomer liquid dispersion of its ester class are become imperceptible particle, reduce the resistance that the alpha-hydroxy organic acid cyclic ester product breaks away from oligomer, to reach the effect of sharp separation alpha-hydroxy organic acid cyclic ester, and thereby reduced the chance that cyclic ester regroups, shortened the cracking time, also therefore reduce the oligomer heated time, and reached the high purpose of product yield.
In detail, the structural formula of alpha-hydroxy organic acid of the present invention is HOCR
1R
2COOH, wherein, R
1With R
2Can be respectively hydrogen atom or contain the alkyl that carbon number is 1-6, the concrete example of alpha-hydroxy organic acid: Alpha-hydroxy acetic acid (α-hydroxyacetic acid, have another name called oxyacetic acid (glycolic acid)), alpha-hydroxypropionic acid (α-hydroxypropionic acid, have another name called lactic acid (lactic acid)), the ester class concrete example of alpha-hydroxy organic acid is as the Alpha-hydroxy ritalin, the Alpha-hydroxy vinyl acetic monomer, the Alpha-hydroxy propyl acetate, the Alpha-hydroxy N-BUTYL ACETATE, the alpha-hydroxypropionic acid methyl esters, ethyl, the alpha-hydroxypropionic acid propyl ester, alpha-hydroxypropionic acid butyl ester etc.; But alpha-hydroxy organic acid or its esters monomer should direct polymerization become the polymkeric substance of alpha-hydroxy organic acid or its ester class, but because the existence of the free acid group of alpha-hydroxy organic acid generally can't continue polymerization again when being aggregated to the oligomer of alpha-hydroxy organic acid or its ester class; But if the oligomer of alpha-hydroxy organic acid or its ester class is behind Pintsch process, can obtain alpha-hydroxy organic acid cyclic ester, these cyclic ester molecules have certain physical character, can utilize separation method that acid group is removed, become high-molecular weight α-poly-hydroxy organic acid ester polymer with the cyclic ester ring-opening polymerization behind the purifying again.
The weight average molecular weight of oligomer of the present invention there is no specific limited, generally at 300-20, and 000, be preferably 400-10,000, also good is 400-5,000.
The concrete example of alpha-hydroxy organic acid cyclic ester of the present invention: its chemical formula is as follows:
The typical example of alpha-hydroxy organic acid cyclic ester, for example: glycollide (glycolide) and LL-rac-Lactide (LL-lactide), DD-rac-Lactide (DD-lactide) or meso-rac-Lactide (meso-lactide).
The oligomer of alpha-hydroxy organic acid of the present invention or its ester class can add suitable catalyst when polymerization, the catalyst that is generally used in the oligomer of making alpha-hydroxy organic acid or its ester class is for example: the oxide-base (oxide) of periodictable IV, V, VIII metal, halide based (halogenide) or carboxylic acid ester groups (carboxylate), concrete example is as antimonous oxide Sb
2O
3, stannic oxide (SnO), tindichloride (SnCl
2), two-(2-ethylhexyl carboxylicesters) tin (Stannous bis (2-ethylhexylcarboxylate)), the usage quantity of catalyst is decided according to response situation, be generally preferable with respect to the 0.1-1.5 weight part of reactant 100 weight parts, the oligomer of alpha-hydroxy organic acid or its ester class also can add suitable solvent when polyreaction, part superheating phenomenon during with the attenuating polymerization, polymerization temperature is about 100-200 ℃, polymerization time was about 15 minutes-10 hours, and meeting produces water by product partly in polymerization process.
The oligomer of alpha-hydroxy organic acid of the present invention or its ester class becomes under the temperature of alpha-hydroxy organic acid cyclic ester can decomposing oligomer effectively, handle the manufacture method that obtains aforementioned alpha-hydroxy organic acid cyclic ester with the hypergravity device, aforementioned what is called " can be decomposed the temperature that oligomer becomes alpha-hydroxy organic acid cyclic ester effectively " and is meant that oligomer is decomposed into the cracking temperature of alpha-hydroxy organic acid cyclic ester, for example with LL-rac-Lactide (LL-lactide), its temperature of decomposing oligomer effectively is generally 150-350 ℃, be preferably 160-320 ℃, also good is 170-280 ℃.The well heater that the oligomer of above-mentioned alpha-hydroxy organic acid or its ester class uses, its preferable Heating temperature be about 150-350 ℃, and temperature is during less than 150 ℃, and the oligomer lysis efficiency of alpha-hydroxy organic acid or its ester class is poor; Temperature easily causes the oligomer carbonization, produces the not product of the optically active meso-rac-Lactide of tool (meso-lactide) during greater than 350 ℃.
As shown in Figure 1, hypergravity device of the present invention (10) essential structure is for producing the device of centrifugal force in high speed rotating mechanism mode.High speed rotating mechanism can comprise a high-speed motor (11), one axle center (12) and be connected with axle center (12) one on, lower rotating disc (13) (15) is formed, start the above-mentioned axle center (12) of drive by above-mentioned high-speed motor (11) and produce the hypergravity condition with this rotating disk (13) (15) high speed rotating, and last, also be provided with a cellular structure (14) between lower rotating disc (13) (15), above-mentioned cellular structure (14) can be foamed metal (foam metal), or gauze packing (packing), this kind foamed metal or gauze packing have the plural hole of aperture 0.01mm-20mm etc.
After the oligomer of above-mentioned alpha-hydroxy organic acid or its ester class or the alpha-hydroxy organic acid cyclic ester liquid after the cracking enter the hypergravity device, run into the lower rotating disc (15) of high speed rotating, and outwards got rid of by centrifugal force, through cellular structure (14), cut in half, be cut to four again, constantly cut to and to become superfine little liquid particle at last, above-mentioned tiny liquid particle (disperse phase) is made liquid-gas with the gas (external phase) that injects current-carrying gas or reactant/resultant itself in addition from hypergravity device outside and is contacted, finish the transfer action of alpha-hydroxy organic acid cyclic ester, again by current-carrying gas take out of system outside.The aforementioned particles particle diameter is generally 10
-1To 10
-3Mm, the control of grain diameter is relevant with the operational condition of hypergravity device, for example: the property of raw material such as viscosity of the rotating speed of rotating disk, the pore size of cellular structure and thickness and reactant/resultant itself; And the hypergravity device can adiabatic heat-insulation or is heated with heating unit.
The sphere of gravity of the hypergravity device that the present invention uses is at 10G-1000G, use the hypergravity device that great advantage is arranged: 1, because the reticulated structure of high speed rotating, making radially, (radius direction) progressive drop is cut into superfine liquid pearl, increase the surface-area of liquid, reached the purpose of gas-liquid intimate contact.2, because liquid has been dispersed into the great liquid pearl of surface-area, so the volume of current-carrying gas do not need too greatly, reduced the puzzlement of product separation in a large amount of gases.3, it is extremely strong to have its penetration power of radially liquid pearl of hypergravity, is not subject to reverse and the current-carrying gas influence that comes and cause overflow phenomena (flooding), therefore can reduce the volume of traditional cracking or separating device.4, because of each dropping liquid pearl all has great G value, reverse current-carrying gas can't blow out it, so the product that carrying object is taken out of do not contain lactic acid oligomer, has simplified follow-up separation and purification of products step.
Hypergravity device of the present invention (10) also comprises a liquid inlet (21), one current-carrying gas inlet (22), one liquid exit (23), one current-carrying gas outlet (24), liquid inlet (21) supplies the liquid of the alpha-hydroxy organic acid cyclic ester of the oligomer of alpha-hydroxy organic acid or its ester class and the split product that part is oligomer to enter, for reaching dispersion effect, can establish a plurality of squit holes (sprayhole) at the end of its admission port, and the center of going up rotating disk (13) partly hollows out and with the upper head plate (26) of pipe core (25) coupling device, the fixed part of pipe core (25) rotating element and upper head plate (26) must seal with axle and connect airtight in case leak-stopping gas.In order to prevent the loss of heat, the outside interlayer of hypergravity device can be made a thermal insulation layer, can also add a thermal insulation layer in addition in circulation line and the every facility of hypergravity device.
Current-carrying gas of the present invention is preferably a rare gas element, comprise that stable gas of any effect does not take place with oligomer for nitrogen, carbonic acid gas, helium or other, wherein preferable with nitrogen, rare gas element is for being steady state under operating temperature and pressure, the flow velocity of current-carrying gas does not need special restriction, gets final product doing the transmission of gas-liquid quality with imperceptible drop and/or film; Current-carrying gas volumetric flow rate of the present invention there is no specific restriction with the oligomer volume flow ratio that enters the hypergravity device, is generally below 1000: 1, is preferably below 200: 1, and also good is below 85: 1; When current-carrying gas volumetric flow rate and the volume flow ratio that enters the liquid form mixt of hypergravity device are 1000: 1 when following, more can not enter the problem that reactive tank causes temperature reduction in the groove and overflow (flooding) because of a large amount of current-carrying gas.For avoiding reducing because of the inflow of gas the temperature of rotating bed, aforementioned current-carrying gas also can enter under heating again, so can improve oligomer cracked speed, reduces the cracking time; The current-carrying gas temperature range there is no specific limited, ℃ is good with room temperature-300 generally.
The oligomer of alpha-hydroxy organic acid of the present invention or its ester class utilizes the hypergravity device to generate the production system of alpha-hydroxy organic acid cyclic ester, comprises shown in batch hypergravity cracking system (as Fig. 2) and the continous way hypergravity cracking system (as Fig. 3).Batch hypergravity cracking system be with oligomer pumping liquid circulation groove in, oligomer is carried in the rotating disk (13) of heater via (31) the laggard excess of imports gravity installation of heating (10) with a feeding manner, in addition, current-carrying gas flows into from the ingress of device (10), on the process, cellular structure (14) between lower rotating disc (13) (15) (please cooperate and consult Fig. 1), current-carrying gas and oligomer liquid carry out the gas-liquid material and transmit in this zone, current-carrying gas is taken the cracked alpha-hydroxy organic acid cyclic ester out of from pipe core (25), except alpha-hydroxy organic acid cyclic ester, still contained alpha-hydroxy organic acid by carry-over, compositions such as water; Obtain alpha-hydroxy organic acid cyclic ester crude product (in the crude product, more than the about 60 weight % of alpha-hydroxy organic acid cyclic ester content) after will being washed by the absorption cell (32) that absorption agent is housed by carry-over again.The absorption agent of above-mentioned use is the solvent that can mix with cyclic ester, for example acetone (acetone), toluene, isopropyl alcohol (isopropyl alcohol) etc.
And continous way hypergravity cracking system, be that oligomer is placed a liquid feeding be pickled with grains or in wine (41), and the oligomer continous way is sent in the liquid circulation groove (43) with liquid feed pump (42), the liquid level of liquid circulation groove (43) is pumped and is principle can keep liquid circulating pump (44), oligomer liquid is carried heater via (45) heating laggard excess of imports gravity installation (10) again; In addition, current-carrying gas flows into from the ingress of device (10), through the cellular structure (14) between upper and lower rotating disk (13) (15), current-carrying gas and oligomer liquid carry out the gas-liquid material and transmit in this zone, current-carrying gas is taken the cracked alpha-hydroxy organic acid cyclic ester out of from pipe core (25), except alpha-hydroxy organic acid cyclic ester, still contained compositions such as alpha-hydroxy organic acid, water by carry-over.Obtain the alpha-hydroxy organic acid cyclic ester crude product after will being washed by the absorption cell (46) that absorption agent is housed by carry-over again.Current-carrying gas is then sent back in the system with gas recycle pump (48) again after condenser (47) condensation again and is recycled; After installing the outlet outflow, enter liquid circulation groove (43) by the effusive liquid of hypergravity device (10), continue the cracking separation to send hypergravity device (10) after pump delivery heater via (45) heating again back to again.Oligomer is heated above-mentioned continous way hypergravity cracking system for a long time in the liquid circulation groove owing to having avoided, and has therefore reduced many unnecessary side reactions and has produced.
Another concrete example of the present invention is under vacuum state, also can carry out the cracking of oligomer and the separation of rac-Lactide, the concrete example of its production system vacuum hypergravity cracking system as shown in Figure 4.The mode that above-mentioned vacuum state can vacuum pump vacuumizes makes the pressure of hypergravity apparatus system be lower than under the negative pressure state of 760mmHg and carries out, and is preferably between between 600mmHg-0.1mmHg, and is also good between between 200mmHg-0.5mmHg.In addition, also can under aforementioned negative pressure state, cooperate a spot of current-carrying gas of adding to carry out simultaneously.Direct use prolong (52) condensation of collecting of the alpha-hydroxy organic acid cyclic ester that cracking produces is collected.Remaining hypergravity cleavage method is batch cracking or continous way cracking as the aforementioned all.
The cumulated volume characteristic feature of an invention, utilize the hypergravity device that the drop of alpha-hydroxy organic acid or its ester class oligomer and alpha-hydroxy organic acid cyclic ester formation is dispersed into imperceptible particle and/or film, again with after the steam of current-carrying gas and/or reactant/resultant contacts, can effectively reduce the resistance that alpha-hydroxy organic acid cyclic ester breaks away from oligomer, utilize a small amount of current-carrying gas to reach again fast with the isolating function of alpha-hydroxy organic acid cyclic ester, and therefore avoided because of rate of cleavage slow, and cause long-time heating to produce the shortcoming of side reaction, make yield thereby raising.
Description of drawings
Fig. 1 is the structural representation of hypergravity device used herein.
Fig. 2 is the synoptic diagram of used herein batch of method hypergravity cracking system.
Fig. 3 is the synoptic diagram of continous way hypergravity cracking system used herein.
Fig. 4 is the synoptic diagram of vacuum hypergravity cracking system used herein.
Embodiment
For effect of the present invention is described, special with the following example explanation, but it only is a preferable possible embodiments of the present invention, is familiar with people's bodyguard of this skill such as, its modification or change of doing according to the present invention's spirit category is gone back, and all ought to be included in the present patent application claim.
Preparation example 1: the polymerization of lactic acid oligomer:
With lactic raw material (concentration 88 weight %) 1000 grams, be equivalent to pure lactic acid 880 grams, place 2 liters of three mouthfuls of reactor attachings to put water distilling apparatus, feed the small amount of nitrogen aeration and be warming up to 170 ℃ of reactions 2 hours, till no longer including water and steaming, obtain lactic acid oligomer, its molecular weight is 800.
Preparation example 2: the polymerization of oxyacetic acid oligomer:
With oxyacetic acid (concentration 70%) 1000 gram and polytetramethylene glycol ether (polytetramethylene ether glycol; The PTMEG-2000 of Dalian company) 1000 gram and antimonous oxide (Sb
2O
3) 2 grams, place 2 liters of three mouthfuls of reactor attachings to put water distilling apparatus, in the dehydration down of logical nitrogen, 195 ℃ of dehydration temperaturres, dewater to the globule drip the speed of distillating very slow till, full time needs 2 hours approximately, and water is bled off, and connects vacuum system, and under 195-200 ℃, be evacuated to pressure and reduce to 25mmHg, till about 2 hours anhydrous extremely fully the oozing, obtain the oxyacetic acid oligomer, its molecular weight is 2850.
Embodiment 1
Use batch method hypergravity cracking system as shown in Figure 2, preparation example 1 prepared lactic acid oligomer is added in the liquid circulation groove, with pump a lactic acid oligomer batch conveying heater via is heated again, after 190 ℃ of the interior lactic acid oligomer arrival of the well heater temperature, the lactic acid oligomer major part is cracked into the rac-Lactide of liquid.Again the liquid mixture of aforementioned lactic acid oligomer and rac-Lactide is sent in the rotating disk of hypergravity device rotating disk rotating speed 1300rpm, aforementioned liquids volume of mixture flow 0.35 (L/min); In addition, one current-carrying gas (nitrogen) flows into from hypergravity device portal place, current-carrying gas volumetric flow rate 35 (L/min), 63 ℃ of current-carrying gas temperature, the ratio of gas-liquid volumetric flow rate (current-carrying gas volumetric flow rate (L/min)/liquor charging body volumetric flow rate (L/min)) is 100, on the process, cellular structure thing (charges) between lower rotating disc, current-carrying gas and lactic acid oligomer and rac-Lactide liquid carry out the gas-liquid quality and transmit in this zone, current-carrying gas is taken with the fastest speed the cracked rac-Lactide out of from pipe core, by the absorption cell washing of acetone agent is housed, the treatment time of hypergravity device is 3.5 hours.After reaction finishes, the acetone liquid that is loaded with the rac-Lactide crude product is extracted acetone and water with the vacuum vaporizer that circles round, obtain rac-Lactide crude product 648 grams.Crude product is through gas chromatographic analysis instrument (GC analysis), and wherein lactic acid accounts for 15.1 weight %, and meso-rac-Lactide accounts for 6.86 weight %, LL-rac-Lactide 77.48 weight %, and DD-rac-Lactide 0.56 weight %, all rac-Lactide accounts for 84.9 weight % altogether.Current-carrying gas then again after condenser condenses again to recycle in the gas circulation pumped back system.In addition, the liquid of uncracked lactic acid oligomer/rac-Lactide enters the liquid circulation groove after the outlet of hypergravity device is flowed out, and continues cracking to send the hypergravity device again back to after the heating of pump delivery heater via again, to finish scission reaction.The operational condition of embodiment 1 and last yield are listed in table one; The yield system of the rac-Lactide of embodiment 1 (comprising meso-rac-Lactide, LL-rac-Lactide, DD-rac-Lactide) is calculated and is got by following formula: (lactic acid of 880 grams can make 703 gram rac-Lactides in theory)
648 gram * 84.9%=550 gram
550/703＝78.3％
Embodiment 2
Lactic acid oligomer cracking operation method is as embodiment 1, and carries out batch hypergravity cracking system according to the operational condition of table one, obtains rac-Lactide crude product 626 grams, and the content of rac-Lactide is 83.4 weight % in the crude product, and the yield of rac-Lactide is:
626 gram * 83.4%=522 gram
522/703＝74.3％
Embodiment 3
Use continous way hypergravity cracking system as shown in Figure 3, in preparation example 1 prepared lactic acid oligomer pumping liquid feed chute, with fresh feed pump lactic acid oligomer is slowly sent in the liquid circulation groove, the liquid level of liquid circulation groove is a principle can keep that liquid circulating pump pumps, again lactic acid oligomer liquid is delivered to well heater, heating back lactic acid oligomer arrives 190 ℃ of temperature, and the lactic acid oligomer major part is cracked into liquid rac-Lactide; Again the liquid mixture of aforementioned lactic acid oligomer and rac-Lactide is sent in the rotating disk of hypergravity device rotating disk rotating speed 1300rpm, aforementioned liquids volumetric flow rate 0.7 (L/min); In addition, one current-carrying gas (nitrogen) flows into from hypergravity device portal place, current-carrying gas volumetric flow rate 35 (L/min), the ratio of 50 ℃ of gas-liquid volumetric flow rates of current-carrying gas temperature (current-carrying gas volumetric flow rate (L/min)/liquor charging body volumetric flow rate (L/min)) is 50, on the process, cellular structure thing (charges) between lower rotating disc, current-carrying gas and lactic acid oligomer and rac-Lactide liquid carry out the gas-liquid quality and transmit in this zone, current-carrying gas is taken with the fastest speed the cracked rac-Lactide out of from pipe core, by obtaining alpha-hydroxy organic acid cyclic ester crude product 622 grams after the absorption cell washing that the acetone agent is housed, the content of rac-Lactide is 87.2 weight % in the crude product.Remaining alpha-hydroxy organic acid and a small amount of oligomer then pump in the aforesaid liquid feed chute and recycle, to constitute a round-robin cracking system, the treatment time of hypergravity device is 3.5 hours, and current-carrying gas is then sent back in the system with recycle pump again after condenser condenses again and recycled.The operational condition of embodiment 3 and last yield are listed in table one; The yield of the rac-Lactide of embodiment 3 is calculated and is got by following formula: (lactic acid of 880 grams can make 703 gram rac-Lactides in theory)
622 gram * 87.2%=542 gram
542/703＝77.1％
Embodiment 4-11
Lactic acid oligomer cracking operation method is as embodiment 3, and carries out continous way hypergravity cracking system according to the operational condition of table one and table two, obtains the rac-Lactide crude product, and the yield that calculates rac-Lactide is shown in table one and table two.
Use vacuum hypergravity cracking system as shown in Figure 4, undertaken by the batch cleavage method.Preparation example 1 prepared lactic acid oligomer is added in the liquid circulation groove, bleed with high-vacuum pump system pressure is reduced to 10mmHg, with liquid circulating pump lactic acid oligomer is carried the heater via heating with batch again, the lactic acid oligomer temperature after heating reaches 192 ℃ in the well heater, the lactic acid oligomer major part is cracked into liquid rac-Lactide compound, again the liquid mixture of aforementioned lactic acid oligomer and rac-Lactide is sent in the rotating disk of hypergravity device and entered, operational condition according to table two obtains rac-Lactide crude product 605 grams, the content of rac-Lactide is 87.4 weight % in the crude product, and the yield of rac-Lactide is:
605 gram * 87.4%=528.8 gram
528.8/703＝75.2％
Hypergravity cracking system operational condition according to embodiment 1, but changing preparation example 2 prepared oxyacetic acid oligomers into adds in the liquid circulation groove, and carry out batch hypergravity cracking system according to the operational condition of table two, obtain glycollide crude product 491 grams, the content of glycollide is 71.4 weight % in the crude product, and the yield that calculates glycollide is: (oxyacetic acid of 700 grams can make 534 gram glycollide in theory)
491 gram * 71.4%=350 gram
350/534＝65.6％
The subordinate list explanation:
Table one is operational condition and the last yield of embodiment of the invention 1-7.
Table two is operational condition and the last yield of embodiment of the invention 8-13.
Table one: the operational condition of the embodiment of the invention 1～7 and last yield
| Embodiment 1 | Embodiment 2 | Embodiment 3 | Embodiment 4 | Embodiment 5 | Embodiment 6 | Embodiment 7 | |
| The mode of production | Batch | Batch | Continuously | Continuously | Continuously | Continuously | Continuously |
| Lactic acid (weight in grams) | 880 | 880 | 880 | 880 | 880 | 880 | 880 |
| Lactic acid oligomer temperature in the well heater (℃) | 190 | 193 | 190 | 193 | 197 | 225 | 192 |
| Rotating disk rotating speed (rpm) | 1300 | 1300 | 1300 | 1300 | 1300 | 1300 | 1300 |
| Liquid volume flow (L/min) | 0.35 | 0.2 | 0.7 | 0.35 | 0.35 | 0.7 | 0.7 |
| Current-carrying gas volumetric flow rate (L/min) | 35 | 20 | 35 | 35 | 70 | 35 | 35 |
| The current-carrying gas temperature (℃) | 63 | 83 | 50 | 60 | 47 | 85 | 127 |
| The solution-air volume flow ratio | 100 | 100 | 50 | 100 | 200 | 50 | 50 |
| Treatment time (hour) | 3.5 | 6 | 3.5 | 4 | 4 | 1.5 | 3.5 |
| Weight of crude product (gram) | 648 | 626 | 622 | 678 | 597 | 677 | 583 |
| Lactide content in the crude product (weight %) | 84.9 | 83.4 | 87.2 | 87.4 | 87.7 | 97.4 | 93.6 |
| The yield of rac-Lactide (%) | 78.3 | 74.3 | 77.1 | 84.3 | 74.5 | 90.6 | 77.6 |
Table two: the operational condition of the embodiment of the invention 8～13 and last yield
| Embodiment 8 | Embodiment 9 | |
|
|
Embodiment 13 (*) | |
| The mode of production | Continuously | Continuously | Continuously | Continuously | Batch | Batch |
| Lactic acid (weight in grams) | 880 | 880 | 880 | 880 | 880 | 700 (oxyacetic acids) |
| Lactic acid oligomer temperature in the well heater (℃) | 192 | 193 | 275 | 192 | 192 | 255 |
| Rotating disk rotating speed (rpm) | 2000 | 600 | 1300 | 1300 | 1300 | 1300 |
| Liquid volume flow (L/min) | 0.7 | 0.7 | 0.7 | 0.7 | 0.7 | 0.7 |
| Current-carrying gas volumetric flow rate (L/min) | 35 | 35 | 35 | 35 | - | 35 |
| The current-carrying gas temperature (℃) | 63 | 68 | 50 | 73 | - | 45 |
| The solution-air volume flow ratio | 50 | 50 | 50 | 50 | - | 50 |
| Treatment time (hour) | 4.5 | 4 | 1.5 | 4 | 4.5 | 3.5 |
| Weight of crude product (gram) | 674 | 633 | 643 | 685 | 605 | 491 |
| Lactide content in the crude product (weight %) | 93.1 | 88.5 | 90 | 89.3 | 87.4 | (71.4 glycollide) |
| The yield of rac-Lactide (%) | 89.2 | 79.7 | 82.3 | 87 | 75.2 | (65.6 glycollide) |
* embodiment
13: glycollide
Manufacturing side
Method
Claims (9)
1. manufacture method with following formula alpha-hydroxy organic acid cyclic ester:
Wherein, R
1With R
2Be respectively hydrogen atom or contain the alkyl that carbon number is 1-6;
It is with alpha-hydroxy organic acid or the formed oligomer of its ester class, become under temperature 150-350 ℃ of alpha-hydroxy organic acid cyclic ester in decomposing oligomer effectively, handle obtaining aforementioned alpha-hydroxy organic acid cyclic ester with the hypergravity device.
2. according to the manufacture method of the described alpha-hydroxy organic acid cyclic ester of claim 1, it is characterized in that wherein the chemical formula of alpha-hydroxy organic acid is HOCR
1R
2COOH, and R
1, R
2Be respectively hydrogen atom or contain the alkyl that carbon number is 1-6.
3. according to the manufacture method of the described alpha-hydroxy organic acid cyclic ester of claim 2, it is characterized in that wherein alpha-hydroxy organic acid is a lactic acid.
4. according to the manufacture method of the described alpha-hydroxy organic acid cyclic ester of claim 1, it is characterized in that wherein alpha-hydroxy organic acid cyclic ester is a rac-Lactide.
5. according to the manufacture method of the described alpha-hydroxy organic acid cyclic ester of claim 1, it is characterized in that wherein the hypergravity device has a high speed rotating mechanism.
6. according to the manufacture method of the described alpha-hydroxy organic acid cyclic ester of claim 5, it is characterized in that wherein the high speed rotating mechanism of hypergravity device has a cellular structure.
7. according to the manufacture method of the described alpha-hydroxy organic acid cyclic ester of claim 1, it is characterized in that wherein the hypergravity device imports current-carrying gas.
8. according to the manufacture method of the described alpha-hydroxy organic acid cyclic ester of claim 7, it is characterized in that wherein current-carrying gas is a rare gas element.
9. according to the manufacture method of the described alpha-hydroxy organic acid cyclic ester of claim 1, it is characterized in that wherein the hypergravity device is to carry out under vacuum state.
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| CNB2005101377415A CN100545159C (en) | 2005-12-19 | 2005-12-19 | The manufacture method of alpha-hydroxy organic acid cyclic ester |
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| CN100545159C true CN100545159C (en) | 2009-09-30 |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN106749160A (en) * | 2016-11-23 | 2017-05-31 | 南京工业大学 | A kind of method that lactide is prepared by high-gravity technology |
| CN107824342B (en) * | 2017-12-04 | 2024-02-06 | 中国恩菲工程技术有限公司 | Supergravity grading process system |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1056877A (en) * | 1990-05-03 | 1991-12-11 | 纳幕尔杜邦公司 | The method of improved quick production cyclic ester class |
| CN1061222A (en) * | 1990-09-18 | 1992-05-20 | 巴特尔纪念研究院 | Produce rac-Lactide by dehydration of aqueous lactic acid feed |
| CN1136309A (en) * | 1993-09-29 | 1996-11-20 | 拜奥帕克技术有限公司 | Method to produce cyclic esters |
| US6187901B1 (en) * | 1997-02-14 | 2001-02-13 | Fortum Oil And Gas Oy | Method for the removal and recovery of lactide from polylactide |
| CN1498237A (en) * | 2001-03-19 | 2004-05-19 | 天藤制药株式会社 | Process for preparing lactic acid oligomer |
-
2005
- 2005-12-19 CN CNB2005101377415A patent/CN100545159C/en not_active Expired - Fee Related
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1056877A (en) * | 1990-05-03 | 1991-12-11 | 纳幕尔杜邦公司 | The method of improved quick production cyclic ester class |
| CN1061222A (en) * | 1990-09-18 | 1992-05-20 | 巴特尔纪念研究院 | Produce rac-Lactide by dehydration of aqueous lactic acid feed |
| CN1136309A (en) * | 1993-09-29 | 1996-11-20 | 拜奥帕克技术有限公司 | Method to produce cyclic esters |
| US6187901B1 (en) * | 1997-02-14 | 2001-02-13 | Fortum Oil And Gas Oy | Method for the removal and recovery of lactide from polylactide |
| TW555791B (en) * | 1997-02-14 | 2003-10-01 | Fortum Oil & Gas Oy | Method for the removal and recovery of lactide from polylactide |
| CN1498237A (en) * | 2001-03-19 | 2004-05-19 | 天藤制药株式会社 | Process for preparing lactic acid oligomer |
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