Lipase Catalysed Synthesis of Bio-based Reactive Polyester

Lipase Catalysed Synthesis of Bio- found Reactive Polyester act OF THE RESEARCH makeup jet polymer chemistry lipase catalysed price reduction of bio-based antiphonal polyester employing itaconic anhydride as re cleanable monomer. diary Polymer Journal (2014) 46, 213INTRODUCTIONSUMMARYThis makeup is several(prenominal) the lipase catalysed tax write-off of reactive polyester. In this synthesis lipase utilize as essential accelerator pedal. The synthesis of reactive polyester was do by isthmus opening sum condensation polymerisation (ROACP) response with vapor. Cyclic anhydride and ethanediol were customd. Itaconic anhydride (IAn) is renewable bio draw visible so it was ideal monomer for synthesis of reactive polyester. IAn is five membered cyclical anhydride. ROACP did not executable in the midst of IAn and diol so the monomer succinic anhydride (SAn) or glutaric anhydride (GAn) were used with IAn and diol. The diol used were 1, 4- howeveranediol (BD), 1, 6-he xanediol (HD), 1, 8-octanediol (OD) and 1, 10-de give the axeediol (DD). ROACP answer of IAn with the diols in the ratios of IAn diol with lipase as a catalyst in presence of molecular sieves were studied at 25C in toluene for 120h. From the GPC depth psychology it is observed that every last(predicate) the response re principal(prenominal)ed inhomogenous du isthmus the reply and gave sole(prenominal) depression-molecular freight product with Mn amongst 150 and 390. The proton magnetic resonance case instal that starting IAn completely consumed in ring opening reply so IAn whole does not video display RCACP so the addition of other component or changing reaction condition necessary. For these regioselectivity and substrate selectivity examination of IAn done by use determine reaction of IAn and n-octyl inebriant. For regioselectivity observation ROA reaction was performed with Novoenzyme 435 catalyst without molecular sieve in toluene at 25C with stirring. The -sele ctivity assess without lipase was 90% and with lipase contact action was 49%. It was because the -carbonyl group is steric all in ally more favourable than -carbonyl group group beside to the vinylidene group so it confirmed that reaction catalysed by lipase. In ROACP reaction first ring opening addition (ROA) reaction between cyclic anhydride and diol and after that dehydration condensation reaction between alcoholic beverage group and carboxylic time period group legislate. let out of four diol OD gives redeeming(prenominal) result in hurt of yield, molecular weight and number of unit per molecule. ROACP exploitation IAn, SAn or GAn and diol produced polyester in good yield. From the SAn polyester with Mn value of 650-3510 with 1.3-2.6 units per molecule were obtained and from GAn these value were 560-3690 and 1.2-3.1 respectively. The polymer synthesized engage application as macromonomer, telechelic or crosslinking reagent.2. LITERATURE SURVEYThe review of this manusc ript and presentation of perspectives has been conducted based on an extensive survey of the manuscripts describing similar or relate research.renewable biobased polymeric sensibles facile synthesis of itaconic anhydride-based copolymers with poly(L-lactic acid) grafts (Okuda et.al, 2012)Biobased material are environmental affectionate so these material now a days used in general for synthesis organic compound. Current opus used itaconic anhydride (IAn) and lactic acid (LA) as a renewable starting material for synthesis of biobased polymeric material of poly (lactic acid) (PLA)-graft copolymer. Synthesis of Poly (lactic acid) (PLA) was done by two way ring-opening polymerization of lactide with a variety of metal or nonmetal catalysts and direct polycondensation of lactic acid (LA) with acid catalysts. Poly (lactic acid) (PLA)-graft copolymer were synthesized by two way macromonomer approach and copolymer approach. get-go the utilise IAn the methacryloyl-type polymerizable PLA macromonomer (IAn-PLA Macro) were formed and then its copolymerization with n-butyl methacrylate (BMA), n-butyl acrylate (BA), methyl methacrylate (MMA) or ethyl methacrylate (EMA) to give graft copolymer with molecular weight Mn up to 1.61105and biomass sate more than 34wt%. When copolymer approached employing IAn as comonomer for radical polymerization with BMA used then IAn-BMA copolymer with Mn 5.76104 obtained. These two approaches are used for synthesis of PLA-graft copolymer as biomass plastic having respective(a) application.2).enzymatic Polymerization A New Method of Polymer Synthesis (kobayashi 1999)enzymatic polymerization refers to polymerization utilise an isolated enzyme outside the bio tenacious system finished non-biosynthetic pathways. The present article gives idea about development of enzymatic polymerization technique. Hydrolases and oxidoreductase types of enzyme were used for polymerization. By using these enzymatic polymerization method miscellaneous material synthesized including polysaccharide like chitin, cellulose, xylan and amylose and un-natural polysaccharide by glycosidase through unhomogeneous monomer. Oxidoreductase initiated vinyl polymerization. The polymerizability was depend on ring size, opposing to chemical contact action where ring strain is operative. Enzymatic polymerization has advantages of high selectivity, ability to plump under around the bend condition, catalyst recyclability, and biocompatibility.3. Dehydration polycondensation in water for synthesis of polyesters by lipase catalyst. (Suda et al., 1999)Lipase is natural catalyst used for synthesis of polyester .In the present paper aliphatic polyester was synthesized by dehydration polycondensation in water by using lipase as catalyst. Polymerization was carried out at 45C for 24 h .size exclusion chromatography (SEC) was used for molecular weight determination. Methanol was used for isolation by reprecipitation. Effect of reaction parameter and t he lipase origin on the molecular weight and the polymer yield have been systematically peckerd in the combining of sebacic acid and 1,8-octanediol. When the experiment was carried without the lipase (control experiment) then the polymerization did not occur indicating that polymerization takes place due to lipase as catalyst. The effect of temperature, solvent and fare of enzyme and monomer were systematically measured. When enzyme concentration increased it was observed that the yield was increased. It was seen that monomer amount in any case affected polymerization behaviour .The polymerization behaviour depend on cooking stove distance of the monomer in the polymerization of a co-dicaboxylic acid and glycol. NMR and MALDI-TOF mass spectrometry was used for terminal structure analysis.4 .Enzymatic polymerization towards perishable polyester nanoparticles (Taden et al., 2003)Biodegradable polymer nanoparticles synthesized from the direct enzymatic polymerization of miniemuls ion consisting of lactone nanodroplets. For polymerization of lactone lipase as catalyst was very efficient. Lipases were ampiphilic molecule and they adsorb onto the hydro-phobic lactone nanodroplets. Ultrasonication was used for the miniemulsification until reaching equilibrium and measure by turbidity measurement. When DSC measurements was done it was observed that the dynamic crystallisation take aim of the synthesized polyester were shifted much down that crystallization inside the droplets was supressed when polymerization condition applied. The thawing point of dried polymer was determined by DSC method. Non-spherical aggregate was formed when crystallization carried out at low temperature. The pH of the minemulsion shifted to 5-6 after polymerization from 7.5. Green Polymer Chemistry Using Natures Catalysts, Enzymes (Pukas et.al, 2009)Enzyme are the natural catalyst. The use of enzyme as a catalyst increases as substitute to chemical catalysis method of organic synthesis. The advantage of enzyme were ability to operate under mild condition, high selectivity, biocompatibility and recyclability. The polymer synthesis was done by enzyme and the most common modelling are polycondensation, oxidative polymerisation and ring opening polymerization. The use of enzyme as a catalyst in polymer science is important methodology for the synthesis of novel polymeric structure, which are impossible or difficult to prepare.3. hypercritical REVIEW3.1 ORIGINALITYThe present paper is about the lipase catalysed synthesis of bio-based reactive polyester employing itaconic anhydride as a renewable monomer. For reducing carbon dioxide emission polymeric material was produced from biobased renewable material. Thus poly-lactic acid has been produced using biobased renewable material. Work on the ring opening polymerization using enzyme catalyst was already done. The elaborate on the lipase catalysed ring opening polymerization of dicarboxlyic acid was first done in 1993 f or the ring opening addition condensation polymerization (ROACP) involving dehydration already carried out. The work on the dehydration in water using lipase catalysed polymerization to formed polyester in water was also done. From the extension of an all these studies the current paper include lipase catalysed synthesis reactive polyester employing itaconic anhydride (IAn), succinic anhydride (SAn) or glutaric anhydride as starting monomer with for diol. Even though the concept was not new but the work done was novel. The author done the work with using new monomer IAn and four diol. ROACP between two monomer itaconic anhydride and diol was not possible so the author added one extra polymer so that reaction completed. root carried out model reaction for getting training about the regioselectivity and substrate selectivity of itaconic anhydride using n-octyl alcohol.3.2 TECHNICAL CORRECTNESSTechnically, this paper is almost correct. All the obtained results have been represented t hrough lucid graphs.DATA REPRESENTATIONAll the employed methods have been soundly-described by the authors. This enabled easy and correct interpretation of some of the related plots and enabled the understanding of the associated concepts. The spectra include in the manuscript clearly represent the results obtained via various experiments and the theoretical discussion supports the results represented in these spectra which enabled better understanding of the experiments and the concepts. liquify OF EXPERIMENTThe flow of the experiments conducted is logical. In the initial part of this paper, the scientists have prone a brief introduction about biobased renewable material. The authors used some references to state the method for poly lactide synthesis using two method ring opening polymerization of lactide and direct polycondensation of lactic. Lipase catalysed ring opening polymerization of dicarboxylic acid anhydride involving dehydration. The reference also included the dehydr ation in water and have conducted green polymer chemistry. To the extension of these work done current paper utilised the itaconic anhydride as a starting biobased monomer to produce a poly (lactic acid) macromonomer.The strategy of synthesis of biobased reactive polyester from itaconic anhydride was like that itaconic anhydride does not react with diol alone so it is necessary that the monomer added so that the reaction was completed therefore succinic anhydride or glutaric anhydride was used in combination. During the synthesis all reaction were remained inhomogenous and gave only low molecular weight product with Mn values between 150 and 390 as determined by GPC analysis. The H NMR studies show that the itaconic anhydride was completely consumed during ring opening reaction. In addition to these EIS-TOF MS analysis show that reaction of itaconic anhydride with diol reaction gives mixture of 11 and 21 adduct of IAn diol. From these it was conclude that in addition to main ROA re action small extent of condensation and dehydration occurred.After these aim the author pointed out why the itaconic anhydride alone does not initialised expected ring opening addition condensation polymerization reaction. The reason behind these was that itaconic anhydride is less(prenominal) reactive than succinic anhydride in dehydration step. The author gives the information from result that ROACP involves two different types of reaction a ROA between diol and cyclic anhydride and dehydration condensation between carboxylic acid group and alcohol group.Author carried out model reaction before the study of the ROACP reaction to obtain valuable information about the product polyester structure and natural aspects of itaconic anhydride. The model reaction carried out using n-octanol instead of a diol. The regioselectivity information obtained from reaction carried out with novoenzyme 435 catalyst without molecular sieve in toluene at 25C. The author interpreted from result that w as obtained from H NMR. The -selectivity value with lipase catalysis was 49% and without lipase catalysis was 90% and thus demonstrate that reaction was governed by lipase catalysis. Author also focus on the substrate selectivity in the reactant in order to prepare reactive polyester. The result from H NMR studies show that after 3h the IAn and SAn were 13% and 27% consumed respectively and without lipase catalyst these reaction did not occur.Author carried ROACP reaction under different condition using IAn, SAn and diol. IAn SAn diol were 2.52.55.0 and 1.4.05.0 taken for synthesis of polyester. When reaction carried out in without novoenzyme 435 no product was formed which insoluble in n-hexane. When the reaction carried out with the lipase but without the molecular sieve, reaction system becomes homogenous to synthesized polymeric product with low Mn .When the molecular sieve were added ROACP was increased and gave the polyester with higher Mn values. Out four diol 1,8-octanediol was the most favourable diol in terms of molecular weight , yield and number of units per molecule. Then paper ended with a detailed discussion on various parameters studied and results observed, which was followed by an appropriate conclusion.3.3 CLARITYIn this paper, the authors have lucidly explained the background of the topic, which gives a clear dogma of the researched topic. Explanation of some concepts enables better understanding of the experiments and reveals the authors logical approach towards the work conducted. Each of the sub-topics well describe the basic concepts cover within them. There is no repetition of matter. Therefore paper is jolly easy to follow and understand.3.4 BIBLIOGRAPHYAuthors have provided 38 references all the references have been cited in course of the discussion. All references are formatted as per guidelines mentioned for authors by the publishers of this scientific journal. Statements in paper can be correctly interpreted by referring to the ci ted references.3.5 TITLE AND ABSTRACTTitle of the paper is Green polymer chemistry lipase catalysed synthesis of bio-based reactive polyester employing itaconic anhydride as renewable monomer. It is self-explanatory. By looking at the title we can get clear idea that the experiment includes synthesis of biobased reactive polyester using itaconic anhydride as a renewable monomer and lipase as a natural catalyst.The pluck of the paper presents an overview of the various studies conducted in the manuscript and briefly presents experimental example and the most important results obtained by the authors. The soak of paper is of appropriate length and sufficient to give clear idea about what work has been done. The abstract brings out all the main points of paper.3.6 ILLUSTRATION AND TABLESThe spectra and graphical representations as well as the table represented in the paper are appropriate. The results discussed in the text are accurately represented in the graphs and spectra. They a re self-explanatory and simple to understand. There searchers have provided the analytical data of material synthesized during their research. This included Mass spectra, proton NMR spectra and IR spectra of precursor material and intermediate synthesized to point out the differences between the various polymer synthesized during the work using different combination of a monomer in different ratio using different diol and different reaction condition as a proof of the polymer being synthesized varies according to a reaction condition and monomer and its concentration.3.7 ALTERNATIVE INTERPRETATIONNo alternative interpretation can be make from the obtained results. All the conclusions made by the author are correct and justify the results obtained.REFERENCES 17 Kobayashi, S. (1999). Enzymatic polymerization a new method of polymer synthesis. J. Polym. Sci. Part a 37, 30413056.26 Suda, S., Uyama, H. Kobayashi, S. (1999). Dehydration polycondensation in water for synthesis of polyest ers by lipase catalyst. Proc. Jpn Acad. B. 75, 201206.29 Taden, A., Antonietti, M. Landfester, K. (2003). Enzymatic polymerization towards biodegradable polyester nanoparticles. Macromol. Rapid Commun. 24, 512516.34 Puskas, J. E., Sen, M. Y. Seo, K. S. (2009). Green polymer chemistry using natures catalyst, enzymes. J. Polym. Sci. Part a 47, 29592976.15 Okuda, T., Ishimoto, K., Ohara, H. Kobayashi, S. (2012). Renewable biobased polymeric materials facile synthesis of itaconic anhydride-based copolymers with poly (L-lactic acid) grafts. Macromolecules 45, 41664174.