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Lactide standard substance as well as preparation method and detecting method thereof
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A standard substance and detection method technology, which is applied in the preparation of test samples, measurement devices, color/spectral characteristic measurement, etc., can solve the problems that the purity cannot reach the standard substance level, complex process equipment, etc.
Inactive Publication Date: 2016-11-23
CENT SOUTH UNIV
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However, there is currently no legal reference material for lactide in China. Since lactide is widely used, in order to meet market demand and facilitate the confirmation and evaluation of analytical methods, instrument calibration, and quality control of relevant enterprises and institutions, a lactide reference material was developed. very necessary
[0004] In the prior art, there are a large number of processes and methods for lactide purification and refining. For example, the application number is 201010180379.0 "Lactide Continuous High Vacuum Distillation and Purification Method" discloses a lactide refining method, but the process of this method Equipment is all comparatively complicated; As application number is 200510094845.2 " a kind of method of lactide recrystallization ", application number is 200710302479.4 " purification method of lactide " discloses lactide purification method, the yield of product has had certain However, its purity has not reached the standard substance level. Therefore, there is still a need for a method that can prepare and mass-produce lactide standard substances through a simple method. Combined value detection
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Embodiment 1
[0077] Preparation of lactide standard substance:
[0078] (1) Dissolution method: Take 300g of lactide raw material, put it in a 1000mL three-necked flask, add 400ml of anhydrousethyl acetate, stir, heat in a 65°C water bath to dissolve completely, and keep warm for 30min.
[0079] (2) Crystallization method: the above solution was cooled at 4° C., and crystallized for 2 hours.
[0081] (4) Drying method: place the crystals in a vacuum oven, and dry under reduced pressure at 40°C and -0.085Mpa for 20 hours to obtain refined lactide.
[0082] (5) Mixing method: put the above-mentioned dried lactide sample in a glass beaker, stir and mix, and the finished product is about 240g.
[0083] (6) Uniformity pre-inspection: take the abo...
Embodiment 2
[0085] (1) Dissolving method: Take 300g of lactide raw material, put it in a 1000mL three-necked flask, add 600ml of absolute ethanol, stir, heat in a water bath at 50°C to dissolve completely, and keep warm for 20min.
[0086] (2) Crystallization method: the above solution was cooled at 10° C., and crystallized for 3 hours.
[0087] (3) Filtration method: Take the above crystallization liquid, filter it with a sand core funnel, rinse the crystals with 120ml of absolute ethanol in 4 times, put the crystals in a tray, and evaporate the solvent at room temperature.
[0088] (4) Drying method: place the crystals in a vacuum oven, and dry under reduced pressure at 30°C and -0.080Mpa for 24 hours to obtain refined lactide.
Embodiment 3
[0090] (1) Dissolution method: Take 300g of lactide raw material, put it in a 1000mL three-necked flask, add 300ml of anhydrousethyl acetate, stir, heat in a water bath at 80°C to dissolve completely, and keep warm for 40min.
[0091] (2) Crystallization method: cool the above solution at 3° C., and crystallize for 1 hour.
[0092] (3) Filtration method: Take the above crystallization liquid, filter it with a sand core funnel, rinse the crystals with 37.5ml of anhydrous ethyl acetate, put the crystals in a tray, and evaporate the solvent at room temperature.
[0093] (4) Drying method: place the crystals in a vacuum oven, and dry under reduced pressure at 60°C and -0.090Mpa for 10 hours to obtain refined lactide.
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Abstract
The invention provides a preparation method for a lactide standard substance. The preparation method comprises the following steps: lactide is heated under a heating condition, and a crystallized product is obtained through filtration after a solution is cooled and crystallized, and is dried under a reduced pressure, wherein the step of dissolution comprises: lactide serving as a raw material is put into a three-necked flask, one or more of heavy alcohol or ester solvents with the weight of one to two times of that of the raw material are added and heated in a water bath at the temperature of 50 to 80 DEG C, stirring is performed completely for dissolution, and standing is performed for preserving the temperature for 20 to 40 minutes; then the solution is cooled at the temperature of three to ten DEG C, and crystallized for one to three hours. The preparation method is simple in preparation process flow and convenient to operate; the purity of the lactide reaches up 90 percent, and meets the requirement on national standard substance. The prepared standard substance is good in uniformity and high in accuracy and stability, has the traceability and a quantity-value transferring function, and can be produced in batches.
Description
technical field [0001] The invention relates to the field of value transfer of metrological tests, in particular to lactide standard substances and the value transfer of metrological tests. Background technique [0002] Lactide is an intermediate for the synthesis of polylactic acid, mainly used in the production of medical high polylactic acid, and a cyclic esterification agent. It is a non-toxic polymer compound and biological material with the most development potential recognized at home and abroad. It has a good biological phaseCapacitance, degradation products can participate in the metabolism of the human body, etc., and are widely used in surgical sutures, drug sustained-release capsules, orthopedic internal fixation materials, etc., and are approved by the US Food and Drug Administration (FDA) for human use. To degrade polymer materials, lactide also has important application value as an intermediate for the synthesis of polylactic acid. Therefore, improving the p...
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