615-95-2Relevant academic research and scientific papers
A study on highly concentrated lactic acid and the synthesis of lactide from its solution
Liu, Lijuan,Xu, Xiaolong
, p. 856 - 864 (2021/06/16)
Lactic acid is an important platform compound used as raw material for the production of lactide and polylactic acid. However, its concentration and composition distribution are not as simple as those of common compounds. In this work, the mass concentration distribution of highly concentrated lactic acid is determined by back titration. The components of highly concentrated lactic acid, crude lactide, and polymer after the reaction are analyzed by HPLC. Different concentrations of lactic acid solution were prepared for the synthesis of lactide and its content in the product was determined by 1H NMR analysis. We found that lactide is more easily produced from high-concentration lactic acid solution with which the condensed water is easier to release. Hence, the removal of condensed water is crucial to the formation of lactide, although it is not directly formed by esterification of two molecules of lactic acid.
SYNTHESIS METHOD AND DEVICE FOR RAPIDLY PRODUCING LACTIDE AT HIGH YIELD
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Paragraph 0050-0114, (2021/06/26)
The invention discloses a synthesis method and device for rapidly producing lactide at high yield. The method comprises: adding a single component of lactic acid or two components of lactic acid and catalyst, passing the mixture through a mixer to enter an oligomer preparation system, increasing a residence time through bottom circulation, synthesizing oligomeric lactic acid, and passing a gas-phase component through a rectification system. With the adoption of the device, the lactide is capable of being efficiently synthesized, crude lactide with a yield of 94% to 98% is capable of being obtained.
Method for catalytically synthesizing lactide
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Paragraph 0056-0076; 0081-0084; 0095-0096; 0099-0100, (2021/01/29)
The invention discloses a method for catalytically synthesizing lactide. According to the method, a mixture of stannous lactate and a urea substance is used as a composite catalyst, L-lactic acid (orD-lactic acid) with the lactic acid content of 90% is used as a raw material, and a reduced pressure distillation technology is adopted to synthesize the L-lactide (or D-lactide). Compared with independent use of onecatalyst, by adopting the composite catalyst, the yield can be effectively increased, under the same experimental conditions, the crude yields of lactide synthesized by independently using stannous lactate or urea catalysts are 69%-72% and 23%-30% respectively, and the yield can be increased to 90% or above by using the composite catalyst of the two. Compared with a traditional tincatalyst or zinc catalyst and other composite catalytic components, the composite catalytic reaction system is low in reaction temperature (150-180 DEG C), short in reaction time (0.5-2 h), high in lactide yield (90% or above), capable of saving more energy and increasing the yield and beneficial to industrial production.
Chemical Recycling of End-of-Life Poly(lactide) via Zinc-Catalyzed Depolymerization and Polymerization
Cheung, Even,Alberti, Christoph,Enthaler, Stephan
, p. 1224 - 1228 (2020/11/03)
The chemical recycling of poly(lactide) was investigated based on depolymerization and polymerization processes. Using methanol as depolymerization reagent and zinc salts as catalyst, poly(lactide) was depolymerized to methyl lactate applying microwave heating. An excellent performance was observed for zinc(II) acetate with turnover frequencies of up to 45000 h?1. In a second step the monomer methyl lactate was converted to (pre)poly(lactide) in the presence of catalytic amounts of zinc salts. Here zinc(II) triflate revealed excellent performance for the polymerization process (yield: 91 %, Mn ～8970 g/mol). Moreover, the (pre)poly(lactide) was depolymerized to lactide, the industrial relevant molecule for accessing high molecular weight poly(lactide), using zinc(II) acetate as catalyst.
METHOD FOR SYNTHESIZING LACTIDE BY MEANS OF CATALYSIS OF LACTID ACID
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Paragraph 0028-0040, (2019/02/24)
The present invention relates to a method for the catalytic synthesis of lactide from lactic acid. The method relates to the synthesis of lactide from lactic acid under the catalysis of a zinc oxide nanoparticle aqueous dispersion as a catalyst. The present invention has four technical characteristics: I. the zinc oxide nanoparticle aqueous dispersion catalyst has a sufficient surface area, and the size of nanoparticles is merely 30-40 nm, providing a sufficient contact area between the substrate (lactic acid) and the catalyst; II. the new catalyst has a milder catalytic effect on polymerization, allowing the molecular weight distribution of a prepolymer within a range of 400-1500 g/mol, which is advantageous for depolymerization to proceed; III. the new catalyst is stable, thus avoiding oxidation or carbonization in a high temperature reaction; and IV. the new catalyst has a low toxicity and a small threat to human health.
Method for synthesizing rod-like long L-lactide crystal with high optical purity
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Paragraph 0017-0035, (2019/01/17)
The invention discloses a method for synthesizing a rod-like long L-lactide crystal with high optical purity, namely the method for synthesizing the rod-like long L-lactide crystal with the high optical purity by utilizing a decompression method with lactic acid as a raw material. A synthesis technology of the rod-like long L-lactide crystal with the high optical purity comprises the following conditions: the amount of a certain amount of the lactic acid is 10-50mL, the volume of a proper amount of catalyst stannous octoate is 1-10mL, the gradually rising temperature range from 90 to 190 DEG C, and the pressure of a reduced pressure distillation reaction is minus 0.10MPa to 0.10MPa, and a certain time is 1-10h. A synthesis method of the rod-like long L-lactide crystal with the high opticalpurity comprises the following steps: 1), taking a certain amount of the lactic acid, adding into a three-necked bottle of 250mL, then adding a proper amount of stannous octoate, gradually heating, and performing a reduced pressure distillation reaction for a certain time to obtain a white lactic acid oligomer; 2), gradually heating the white lactic acid oligomer in a device, and performing the reduced pressure distillation reaction for a certain time until no obvious distillate appears, and collecting the distillate, that is a lactide product, wherein the product is a mixture of D-type lactide and L-type lactide.
Investigation into the Anticancer Activity and Apoptosis Induction of Brevinin-2R and Brevinin-2R-Conjugated PLA–PEG–PLA Nanoparticles and Strong Cell Cycle Arrest in AGS, HepG2 and KYSE-30 Cell Lines
Hassanvand Jamadi, Robab,Asadi, Asadollah,Yaghoubi, Hashem,Goudarzi, Fariba
, p. 1225 - 1239 (2018/10/26)
Our study aims to establish a biocompatible nanostructure for the improved delivery of anticancer peptide, Brevinin-2R, to treat human gastric adenocarcinoma (AGS), human liver hepatocellular carcinoma (HepG2) and human squamous cell carcinoma (KYSE-30) cells. Poly(l-lactide)–poly(ethylene glycol)–poly(l-lactide) (PLA–PEG–PLA) nanoparticles were synthesized, obtained by a solvent evaporation method and characterized using scanning electron microscopy (SEM), FTIR and DLS; chemically-synthesized Brevinin-2R was encapsulated in micelles. In vitro release and cell uptake assay were conducted before cytotoxicity tests. Cell cycle analysis and apoptosis study were performed through flow cytometry and Annexin-V-FlOUS cell staining. PLA–PEG–PLA nanoparticles showed a narrow-size distribution with a zeta potential of ? 26.63 and a high cell internalization. Brevinin-2R-conjugated nanoparticles were spherical in shape with an increased surface charge of ? 21.90. For the first time, viability tests showed that Brevinin-2R-conjugated nanoparticles were more efficient than Brevinin-2R against cancer cells causing higher rates of cell cycle arrest and apoptosis induction. Our new findings demonstrate the potential of PLA–PEG–PLA nanoparticles to boost the anticancer effect and improve the delivery of Brevinin-2R. The study of Brevinin-2R-loaded nanoparticles indicated noticeable results in terms of novel cancer therapy. PLA–PEG–PLA nanoparticles can act as a biocompatible delivery platform to take the advantage of Brevinin-2R toward cancer cells. This is a novel study as the Brevinin-2R-conjugated nanoparticles and applied approaches have not been already reported.
PROCESS FOR PREPARING A CYCLIC DIESTER OR A CYCLIC DIAMIDE BY REACTING A HYDROXYCARBOXYLIC ACID OR AMIDE WITH AN ACIDIC BEA-TYPE (H-BETA POLYMORPH A) ZEOLITE
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Page/Page column 32-33, (2018/10/19)
A process for preparing a cyclic diester or a cyclic diamide by reacting a hydroxycarboxylic acid or amide with an acidic BEA (H-beta polymorph A) type zeolite. The process is characterised in that the total amount of acid sites is in the range of from 0.25 to 1.0 mmol/g and the amount of medium acid sites is at least 40% of the total amount of acid sites. The total amount of acid sites and the amount of medium acid sites are determined by NH3-TPD (temperature-programmed desorption of ammonia). Preferably, the process refers to the preparation of lactide from lactic acid. The framework structure of the zeolitic material comprises Si, Al, O, and H.
Continuous lactide synthesis process and apparatus
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Paragraph 0096; 0097; 0104; 0107; 0112, (2018/10/24)
Lock taken bath used for energy intensive processes the synthesis polylactic acid number are disclosed. In the present invention newly developed SnO2 - SiO2 Nano composite catalyst effect using won - based substrate. The catalyst is fast reaction rates (20 ms) and enabling a 94% yield (highest yield temporal) are used to lock taken number tank. Process of the present invention is rapid kinetics and high yield as well as, the commonly used contrast process has numerous advantages. In addition, the fast reaction rates, its processing amount significantly maxims. In addition, the process of the present invention carried out in atmospheric conditions, the high vacuum conditions (20 mmHg) is operated in a more energy efficient during processes currently used are disclosed. Thus, the process of the present invention can reduce costs associated with polylactic acid number tub. (by machine translation)
In Vitro Characterization and Evaluation of the Cytotoxicity Effects of Nisin and Nisin-Loaded PLA-PEG-PLA Nanoparticles on Gastrointestinal (AGS and KYSE-30), Hepatic (HepG2) and Blood (K562) Cancer Cell Lines
Goudarzi, Fariba,Asadi, Asadollah,Afsharpour, Maryam,Jamadi, Robab Hassanvand
, p. 1554 - 1566 (2018/02/28)
The aim of this study was an in vitro evaluation and comparison of the cytotoxic effects of free nisin and nisin-loaded PLA-PEG-PLA nanoparticles on gastrointestinal (AGS and KYSE-30), hepatic (HepG2), and blood (K562) cancer cell lines. To create this novel anti-cancer drug delivery system, the nanoparticles were synthesized and then loaded with nisin. Subsequently, their biocompatibility, ability to enter cells, and physicochemical properties, including formation, size, and shape, were studied using hemolysis, fluorescein isothiocyanate (FITC), Fourier transform infrared (FTIR) spectroscopy, dynamic light scattering (DLS), and scanning electron microscopy (SEM), respectively. Then, its loading efficiency and release kinetics were examined to assess the potential impact of this formulation for the nanoparticle carrier candidacy. The cytotoxicities of nisin and nisin-loaded nanoparticles were evaluated by using the MTT and Neutral Red (NR) uptake assays. Detections of the apoptotic cells were done via Ethidium Bromide (EB)/Acridine Orange (AO) staining. The FTIR spectra, SEM images, and DLS graph confirmed the formations of the nanoparticles and nisin-loaded nanoparticles with spherical, distinct, and smooth surfaces and average sizes of 100 and 200?nm, respectively. The loading efficiency of the latter nanoparticles was about 85–90%. The hemolysis test represented their non-cytotoxicities and the FITC images indicated their entrance inside the cells. An increase in the percentage of apoptotic cells was observed through EB/AO staining. These results demonstrated that nisin had a cytotoxic effect on AGS, KYSE-30, HepG2, and K562 cancer cell lines, while the cytotoxicity of nisin-loaded nanoparticles was more than that of the free nisin.
