cas 4511-42-6, L-Lactide | Articles data

Articles about 4511-42-6Total 35 be found

Article title
Article abstract
Author
Journal number and time
Download

SYNTHESIS METHOD AND DEVICE FOR RAPIDLY PRODUCING LACTIDE AT HIGH YIELD
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.
-
Paragraph 0050-0114

(2021/06/26)

Method for catalytically synthesizing lactide
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.
-
Paragraph 0023-0055; 0077-0080; 0085-0094; 0098-0100

(2021/01/29)

Method for synthesizing rod-like long L-lactide crystal with high optical purity
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.
-
Paragraph 0017-0035

(2019/01/17)

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
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.
Hassanvand Jamadi, Robab,Asadi, Asadollah,Yaghoubi, Hashem,Goudarzi, Fariba
p. 1225 - 1239
(2018/10/26)

Catalytic Gas-Phase Cyclization of Glycolate Esters: A Novel Route Toward Glycolide-Based Bioplastics
A catalytic process to produce glycolide, the cyclic dimer of glycolic acid (GA), is proposed. Glycolide is the key building block of the biodegradable plastic polyglycolic acid. Instead of the current industrial two-step route, which involves the polycondensation of GA and a subsequent backbiting reaction, a new route based on the gas-phase transesterification of methyl glycolate (MGA) over a fixed catalyst bed is presented. With specific supported TiO2 catalysts, a high glycolide selectivity of 75–78 % can be achieved at the thermodynamically-limited equilibrium conversion of MGA (54 % at 300 °C, 5.6 vol% MGA, 1 atm). The absence of solvent and the continuous nature of the process should allow for easy product separation and recycling of unconverted esters, while the few side-products, i. e. linear alkyl glycolate dimers and trimers seem recoverable via methanolysis. The reaction is compared to the cyclization of other α-hydroxy esters, such as methyl lactate to lactide, over the same catalysts, in terms of kinetics and thermodynamics. The absence of a methyl substitution on the α-carbon seems to lead to faster cyclization kinetics of MGA when compared to methyl lactate or the double-substituted methyl-2-hydroxy-isobutyrate. Contrarily, glycolide production is less favored thermodynamically compared to lactide. The absence of glycolide decomposition at temperatures up to 300 °C however allows to increase equilibrium conversion by taking the endergonic reaction to higher temperatures.
De Clercq, Rik,Makshina, Ekaterina,Sels, Bert F.,Dusselier, Michiel
p. 5649 - 5655
(2018/12/04)

Continuous lactide synthesis process and apparatus
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)
-
Paragraph 0096; 0097; 0104; 0107; 0112

(2018/10/24)

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
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.
Goudarzi, Fariba,Asadi, Asadollah,Afsharpour, Maryam,Jamadi, Robab Hassanvand
p. 1554 - 1566
(2018/02/28)

Catalytic Gas-Phase Production of Lactide from Renewable Alkyl Lactates
A new route to lactide, which is a key building block of the bioplastic polylactic acid, is proposed involving a continuous catalytic gas-phase transesterification of renewable alkyl lactates in a scalable fixed-bed setup. Supported TiO2/SiO2 catalysts are highly selective to lactide, with only minimal lactide racemization. The solvent-free process allows for easy product separation and recycling of unconverted alkyl lactates and recyclable lactyl intermediates. The catalytic activity of TiO2/SiO2 catalysts was strongly correlated to their optical properties by DR UV/Vis spectroscopy. Catalysts with high band-gap energy of the supported TiO2 phase, indicative of a high surface spreading of isolated Ti centers, show the highest turnover frequency per Ti site.
De Clercq, Rik,Dusselier, Michiel,Makshina, Ekaterina,Sels, Bert F.
supporting information
p. 3074 - 3078
(2018/03/13)

Production of lactide
Disclosed is a method for producing a lactide using a pyridinium-based catalyst, the method involving esterifying the carboxyl group of a lactic acid oligomer by means of a specific primary alcohol and heating the esterified product thus obtained under reduced pressure.
-
Paragraph 0080-0082

(2017/08/02)

Synthesis of lactide from lactic acid and its esters in the presence of rare-earth compounds
A procedure is described for the synthesis of lactide by dehydration of L-lactic acid and subsequent depolymerization of its oligomer mixture in the presence of yttrium(III) and praseodymium(III) oxides, as well as of cerium(III) chloride heptahydrate. The catalytic activity of yttrium and praseodymium sesquioxides was determined at different temperatures at the oligomerization and deoligomerization stages. Ethyl lactate was prepared in the presence of Purolite C100 MB cation exchange resin and subjected to oligomerization followed by thermal decomposition of oligoester and oligolactic acid mixture in the presence of yttrium(III) and praseodymium(III) oxides and aqueous cerium(III) chloride.
Poryvaeva,Egiazaryan,Makarov,Moskalev,Razborov,Fedyushkin
p. 344 - 350
(2017/05/10)

TECHNOLOGICAL METHOD FOR SYNTHESIS OF OPTICALLY PURE L-/D-LACTIDE CATALYZED BY BIOGENIC GUANIDINE
A technological method for synthesizing optically pure L-/D-lactide by using a biogenic guanidine catalysis method. The method of the present invention comprises: by using biogenic guanidine creatinine (CR) as a catalyst and L-/D-lactic acid (90% of mass content) as a raw material, synthesizing optically pure L-/D-lactide by using a reactive reduced pressure distillation catalysis method. The method of the present invention has advantages that the used catalyst is biogenic guanidine creatinine and free of toxicity, metal, and cytotoxicity; the synthesized lactide is high in optical purity (the specific rotation of the L-lactide [α]25 D=?276??280, and the specific rotation of the D-lactide [α]25 D=280), and does not contain any metal; the amount of the catalyst used in reaction is low, the technological process is simplified (a process for rectifying and purifying a crude lactide product by using a conventional method is avoided); and the technological method is simple and convenient to operate and easy in industrial implementation.
-
Paragraph 0019-0021

(2016/03/26)

Design of a heterogeneous catalytic process for the continuous and direct synthesis of lactide from lactic acid
We present a continuous one-step reaction pathway for optically pure lactide under atmospheric conditions based on a novel SnO2-SiO2 nanocomposite catalyst. The new heterogeneous catalytic system gave a record high lactide yield of 94% with almost 100% enantioselectivity and long-term stability (>2500 h) from l-lactic acid.
Upare, Pravin P.,Yoon, Ji Woong,Hwang, Dong Won,Lee, U-Hwang,Hwang, Young Kyu,Hong, Do-Young,Kim, Jin Chul,Lee, Jeong Hyeon,Kwak, Sang Kyu,Shin, Hyeyoung,Kim, Hyungjun,Chang, Jong-San
p. 5978 - 5983
(2018/06/06)

Preparing method of lactide stereisomer mixture
The invention provides a preparing method of a lactide stereisomer mixture, which comprises: taking an alkali metal compound as a catalyst, performing stereoisomerism reaction on a raw material lactide under a condition of 120-250 DEG C to obtain the stereisomer mixture containing D-, L- and meso- lactide, wherein the catalyst is selected from one or more from hydride, boron hydrogen compound, amide, chloride, bromide, monoiodide, sulfide, chlorate, bromate, iodate, chlorite, hypobromite, perchlorate, perbromate, periodate, sulfite, hydrosulphite, nitrate and nitrite of alkali metal. The specific alkali metal compound is taken as the catalyst for lactide isomerization reaction, the inversion of configuration of the lactide can be efficiently realized in an economic and environment-friendly manner, and the stereisomer mixture containing D-, L- and meso- lactide is prepared.
-
Paragraph 0044; 0045; 0046; 0047; 0048

(2017/01/26)

METHOD FOR PRODUCING LACTIDE DIRECTLY FROM LACTIC ACID AND A CATALYST USED THEREIN
The present invention provides a method for directly producing lactide by subjecting lactic acid to a dehydration reaction in the presence of a catalyst comprising a tin compound, preferably, a tin (IV) compound, wherein lactide can be produced directly or by one step from lactic acid, without going through the step of producing or separating lactic acid oligomer. The method of the present invention has advantages of causing no loss of lactic acid, having a high conversion ratio to lactic acid and a high selectivity to optically pure lactide, and maintaining a long life time of the catalyst. Further, since lactic acid oligomer is not or hardly generated and the selectivity of meso-lactide is low, the method also has an advantage that the cost for removing or purifying this can be saved.
-
Paragraph 0070; 0071

(2015/09/23)

PROCESS FOR PREPARING CYCLIC ESTERS AND CYCLIC AMIDES
The invention relates to a process for preparing a cyclic ester or a cyclic amide, comprising the step of: contacting at least one hydroxycarboxylic acid and/or at least one amino-carboxylic acid; or an ester, or salt thereof; wherein said hydroxycarboxylic acid is a 2-hydroxycarboxylic acid,or a 6–hydroxycarboxylic acid; and wherein said amino carboxylic acid is a 2-amino-carboxylic acid or a 6-amino-carboxylic acid; with at least one acidic zeolite comprising: - two or three interconnected and non-parallel channel systems, wherein at least one of said channel systems comprises 10-or more-membered ring channels; and a framework Si/X2 ratio of at least 24 as measured by NMR; or - three interconnected and non-parallel channel systems, wherein at least two of said channel systems comprise 10-or more-membered ring channels; and a framework Si/X2 ratio of at least 6 as measured by NMR; wherein each X is Al or B, and wherein the process is performed at a pressure between 0.5 and 20 bar.
-
Page/Page column 25-30

(2014/08/20)

Effect of block lengths on the association behavior of poly(l-lactic acid)/poly(ethylene glycol) (PLA-PEG-PLA) micelles in aqueous solution
A series of poly(l-lactic acid)/poly(ethylene glycol) triblock copolymers with a PLA-PEG-PLA architecture were synthesized by a ring-opening polymerization (ROP) process. The copolymers were characterized by 1H NMR and GPC. The total number average molecular weights were in the range of 4,700-50,000, whereas the degrees of polymerization of the PLA and PEG blocks varied from 15 to 359 and from 68 to 136, respectively. The self-association of these copolymers in aqueous environment was studied by emission fluorescence spectroscopy of anilinonaphthalene probe and the critical association concentration (CAC) of the copolymers was measured. It was found that the micellization process of these copolymers was mainly determined by the length of the hydrophobic LA block, while the length of the hydrophilic PEG block had little effect. Furthermore, the low CAC values of the copolymers suggest that the copolymers form stable supramolecular structures in aqueous solutions.
Pourhosseini, Pouneh S.,Amani, Reza,Saboury, Ali A.,Najafi, Farhood,Imani, Mohammad
p. 467 - 470
(2014/04/03)

Process For The Preparation Of L-Lactide Of High Chemical Yield And Optical Purity
A process for the synthesis of 100% optically pure L(+)-lactide catalyzed by zinc and tin metal catalysts of less than 150 micron particle size is disclosed. The L-lactide obtained was further purified to obtain lactide of 100% optical purity and acid impurities less than 10 meq/kg.
-
Paragraph 0064; 0065; 0066; 0067

(2013/03/26)

Method for obtaining lactide
Processes for producing lactide from lactic acid oligomers are described herein. The processes generally include heating a lactic acid oligomer in the presence of a catalyst at a temperature of between 150° C. and 300° C. under a pressure of less than 0.01 MPa to form a lactide; distilling the lactide; and condensing and recovering the lactide, wherein the catalyst is a metal salt of the phosphite anion PO33? in which the metal is selected from the group consisting of tin, aluminum, zinc, titanium and zirconium.
-
Page/Page column 3; 4; 5

(2013/12/03)

Racemization-free synthesis of lactide using an onium salt catalyst
Synthesis of LL-lactide with high chemical, diastereomeric, and enantiomeric purities was achieved by depolymerization of oligo(lactic acid) in the presence of an onium salt catalyst.
Ishijima, Yuuki,Maruta, Yasumi,Abiko, Atsushi
supporting information
p. 1456 - 1458
(2013/01/16)

RECOVERY METHOD OF HIGHLY PURE LACTIC ACID AND ALKYL LACTATE
A method for recovery of highly pure alkyl lactate and lactic acid is provided, which includes a step 1 for producing source liquid comprising lactic acid or ammonium lactate; a step 2 for dehydrating the source liquid product of step 1; a step 3 for producing liquid mixture by sequentially adding and stirring alcohol and acid solution to the dehydrated source liquid; a step 4 for separating and removing ammonium salt precipitation from the liquid mixture of step 3; a step 5 for producing alkyl lactate from ammonium salt-free liquid mixture by esterification reaction; and a step 6 for separating alcohol and alkyl lactate by distillation from the mixture of step 5.
-
Page/Page column 6

(2012/06/16)

Method for the production of a mixture of lactide derivatives
A mixture of cyclic diesters derived from lactic acid and in cases a mixture of a racemate of dilactide may be produced in several different processes. In some instances, the process can thereby start from the corresponding alpha-hydroxycarboxylic acids, the corresponding cyclic diesters or oligomers of the corresponding alpha-hydroxycarboxylic acids.
-
Page/Page column 7

(2012/06/18)

Studies on the epimerization of diastereomeric lactides
The epimerization of chiral lactides was studied in the presence of various homogeneous and heterogeneous bases. Some solvent/base systems were found to promote epimerization at room temperature efficiently. Side reactions such as polymerization were not observed or occurred only slowly. This new protocol offers the opportunity of the transformation of meso-lactide into rac-lactide. Therefore it can reduce the overall manufacturing costs of polylactides, a problem which currently hampers the broad application of those environmentally friendly polymers in a large scale.
Shuklov, Ivan A.,Jiao, Haijun,Schulze, Joachim,Tietz, Wolfgang,Kühlein, Klaus,B?rner, Armin
scheme or table
p. 1027 - 1030
(2011/03/20)

Catalyst for direct conversion of esters of lactic acid to lactide and the method for producing lactide using the same
The present disclosure discloses a catalyst for directly producing a lactide which is a cyclic ester used as a monomer for polylactides, and a method for directly producing a lactide using the catalyst, the method including the transesterification reaction between two molecules of an ester of lactic acid or a mixture containing the ester of lactic acid with a small amount of lactic acid and oligomer of lactic acid under an inert environment in the presence of a titanium-based catalyst or a catalyst mixture containing the titanium-based catalyst so as to produce lactide while simultaneously removing an alcohol (ROH) generated as a by-product. As compared to a conventional commercialized process, since the method for producing a lactide in accordance with the present disclosure is a novel process capable of directly producing the lactide from the ester of lactic acid, energy consumption is low and the lactide can be produced through a simple process showing a high yield while maintaining optical property (D-form or L-form optical isomer).
-
Page/Page column 8; 9

(2011/01/11)

Catalyst For Direct Conversion Of Esters Of Lactic Acid To Lactide And The Method For Producing Lactide Using The Same
The present disclosure discloses a catalyst for directly producing a lactide which is a cyclic ester used as a monomer for polylactides, and a method for directly producing a lactide using the catalyst, the method including the transesterification reaction between two molecules of an ester of lactic acid or a mixture containing the ester of lactic acid with a small amount of lactic acid and oligomer of lactic acid under an inert environment in the presence of a titanium-based catalyst or a catalyst mixture containing the titanium-based catalyst so as to produce lactide while simultaneously removing an alcohol (ROH) generated as a by-product. As compared to a conventional commercialized process, since the method for producing a lactide in accordance with the present disclosure is a novel process capable of directly producing the lactide from the ester of lactic acid, energy consumption is low and the lactide can be produced through a simple process showing a high yield while maintaining optical property (D-form or L-form optical isomer).
-
Page/Page column 6-7

(2010/12/29)

METHODS FOR PRODUCING LACTIDE WITH RECYCLE OF MESO-LACTIDE
An S, S- and R,R-lactide stream suitable for polymerization is prepared by producing a low molecular weight poly(lactic acid), depolymerizing the low molecular weight poly(lactic acid) to form a mixture of S, S-, R,R- and meso- lactide, and separating meso-lactide from this mixture to form an S, S- and R,R- lactide stream. Meso-lactide is recycled into the process, and shifts the mole fractions of the lactides in the lactide mixture that is produced.
-
Page/Page column 32-35

(2010/10/03)

RECOVERY OF LACTIC ACID VALUES FROM A MESO-LACTIDE STREAM
Lactic acid equivalents are recovered from a starting lactide stream by catalytically racemizing a portion of the lactide in the stream at a temperature of 18O°C or below. This increases the proportion of two species of lactide (i.e., at least two of S, S-, R,R- or meso-lactide) at the expense of the third species. The racemized mixture so obtained can be separated to recover some or all of one or more of the lactide species from the remaining lactide species, by a process such as melt crystallization or distillation. Impurities in the starting lactide stream usually are retained mostly in the remaining meso-lactide, so a highly purified S, S- and/or R,R-lactide stream can be produced in this manner. Such a purified S, S- and R,R-lactide stream is suitable for polymerization to form a polylactide.
-
Page/Page column 23; 24

(2010/10/03)

A bifunctional monomer derived from lactide for toughening polylactide
(6S)-3-Methylene-6-methyl-1,4-dioxane-2,5-dione was synthesized from l-lactide and used as the dienophile to prepare spiro[6-methyl-1,4-dioxane-2,5-dione-3,2′-bicyclo[2.2.1]hept[5]ene] via an exoselective and diastereofacial-selective Diels-Alder reaction. Polymerizations of this bifunctional lactide derivative were successfully carried out under ring-opening and ring-opening metathesis polymerization conditions to yield high molecular weight and high Tg polymers. We further demonstrated that by incorporating a small percentage of spiro[6-methyl-1,4-dioxane-2,5-dione-3,2-bicyclo[2.2.1]hept[5]ene] into poly(1,5-cyclooctadiene) and copolymerizing it with dl-lactide, novel polymeric alloys of PLA can be created that have tremendous improvements in toughness over PLA and the corresponding binary blend of PLA and poly(1,5-cyclooctadiene). Copyright
Jing, Feng,Hillmyer, Marc A.
supporting information; experimental part
p. 13826 - 13827
(2009/02/07)

Menthyl lactate process
A simple, high-yield process for making menthyl lactate (ML) is disclosed. Menthol and lactic acid react to produce a mixture comprising menthyl lactate and one or more higher lactoyl esters of ML. Hydrolysis of the esterification mixture follows in the presence of aqueous base under conditions effective to convert the higher lactoyl esters to menthyl lactate. Coincidentally, the conditions minimize hydrolysis of menthyl lactate to menthol, thereby maximizing the overall yield of ML.
-
Page/Page column 5-6

(2008/06/13)

METHOD OF RECOVERING LACTIDE FROM POLYLACTIC ACID OR DERIVATIVE THEREOF
To provide an efficient method for recovering and producing lactide having high optical purity by depolymerizing a polylactic acid or derivative thereof in order to carry out chemical recycling of the polylactic acid or derivative thereof or of a resin composition comprising same, wherein a mixture of a polylactic acid or derivative thereof and aluminum hydroxide is thermally decomposed at a temperature in a range from at least the melting temperature of the polylactic acid or derivative thereof to no greater than 320°C, thus recovering lactide.
-
Page/Page column 8

(2008/06/13)

Method for the productiion of polylactide from a solution of lactic acid or one of the derivatives thereof
A process for the production of polylactide, the stages of which for the production and purification of lactide, starting from an aqueous solution of lactic acid or of its derivatives, includes evaporation of water with formation of oligomers, depolymerization to give lactide, condensation and then crystallization of the crude lactide product to give purified lactide, aqueous treatment of the residual fractions from the crystallization and polymerization of purified and/or prepurified lactide to give polylactide in an extruder and in the presence of catalysts. An alternative process includes carrying out the aqueous treatment before the crystallization.
-
Page/Page column 9-12

(2010/02/15)

PURIFICATION PROCESS FOR LACTIDE
The present case relates to a process for the purification of lactide from a crude lactide vapour product stream which process comprises a rectification/condensation step leading to a lactide-enriched condensate.
-
Page/Page column 17-18

(2010/02/12)

Melt Chain Dimensions of Polylactide
Melt chain dimensions of two polylactide samples were measured using small-angle neutron scattering, Three polylactides were synthesized: a deuterated polylactide containing 26% R-stereocenters (d-PLA-26), a hydrogenous polylactide with an R-content similar to the deuterated polylactide (PLA-28), and a hydrogenous polylactide that contained no R-stereocenters (PLA-0). The hydrogenous polylactides were each solution blended with the d-PLA-26 at a volume fraction of 0.2 for the deuterated polymer, and the melt chain dimensions of these polymers were determined. Small-angle neutron scattering experiments were performed at 30°C for the d-PLA-26/PLA-28 blend and at 200°C for both the d-PLA-26/PLA-28 and d-PLA-26/PLA-0 blends. Using three analysis methods, the average values for the statistical segment lengths, based on a C6 repeat unit, were found to be 10.0 ± 0.2 A for the PLA-28 at 30°C, 8.9 ± 0.2 A for the PLA-28 at 200°C, and 9.9 ± 0.4 A for the PLA-0 at 200°C.
Anderson, Kelly S.,Hillmyer, Marc A.
p. 1857 - 1862
(2007/10/03)

A versatile route to functionalized dilactones as monomers for the synthesis of poly(α-hydroxy) acids
A synthetic pathway to functionalized six-membered dilactones structurally analogous to lactide is described. Through the use of orthogonal protecting groups, the synthesis of functionalized dilactones was performed in a straightforward way by cyanuric chloride-mediated cyclization of the corresponding linear α-hydroxy acid dimers. The synthesis of three different dilactones - methylglycolide, benzyloxymethylglycolide, and 2-benzyloxymethyl-5-methylglycolide - by the same procedure demonstrated the versatility of this route. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003.
Leemhuis, Mark,Van Steenis, Jan Hein,Van Uxem, Michelle J.,Van Nostrum, Cornelus F.,Hennink, Wim E.
p. 3344 - 3349
(2007/10/03)

PROCESS FOR PRODUCING LACTIDE AND PROCESS FOR PRODUCING POLYLACTIC ACID STARTING WITH FERMENTED LACTIC ACID
According to the present invention, a process for consistently producing lactide from ammonium lactate obtained by lactic fermentation, and a process for consistently producing polylactic acid from ammonium lactate obtained by lactic fermentation, are provided. A process for producing lactide, which comprises the steps of: (1) synthesizing lactate ester from ammonium lactate obtained by lactic fermentation; (2) polycondensing the lactate ester in the presence of a catalyst other than monobutyltin, whereby polylactic acid with a weight-average molecular weight of less than 15,000 (lactic acid prepolymer) is synthesized; and (3) depolymerizing the polylactic, whereby lactide is produced. A process for producing polylactic acid, which comprises the additional step of (4) ring-opening polymerizing said lactide, whereby polylactic acid is obtained. A process for producing lactate ester from ammonium lactate obtained by lactic fermentation.
-
Page/Page column 8

(2010/01/31)

Continuous process for the manufacture of lactide and lactide polymers
A process for the continuous production of substantially purified lactide and lactide polymers from lactic acid or an ester of lactic acid including the steps of forming crude polylactic acid, prefereably in the presence of a catalyst means in the case of the ester of lactic acid, to form a condensation reaction by-product and polylactic acid, and depolymerizing the polylactic acid in a lactide reactor to form crude lactide, followed by subsequent purification of the crude lactide in a distillation system. A purified lactide is then polymerized to form lactide polymers.
-
Page 20

(2010/02/05)