Synthesis of poly(lactic acid) by heterogeneous acid catalysis from d,l-lactic acid

Chafran, Liana S.; Campos, Jonas M. C.; Santos, Joicy Santamalvina dos; Sales, Maria J. A.; Dias, Sílvia C.L.; Dias, José A.

doi:10.1007/s10965-016-0976-7

Cited by 19 publications

(23 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The good results obtained with 20 wt.% H 3 PW/C in the polycondensation of D,L-lactic acid [16] prompted us to study other supported H 3 PW systems. The choices of silica and alumina supports were based on the following: i) their wide availability and low cost, and ii) they are catalysts with loadings of 20 wt.% H 3 PW on silica or alumina that have been studied and characterized by our group [24, 25, 26].…”

Section: Resultsmentioning

confidence: 99%

“…Solutions of H 3 PW (H 3 PW 12 O 40 nH 2 O, 99.9%, obtained from Sigma, USA) in 0.1 mol L -1 hydrochloric acid (HCl, acquired from Vetec, Brazil) were prepared to attain 20, 30, and 40 wt.% H 3 PW on the supports (activated carbon, silica, and alumina, purchased from Aldrich, USA). The detailed procedure can be found elsewhere [16]. The prepared catalysts were subjected to different calcination temperatures (200, 300, and 400 °C) in a muffle furnace (EDG model 3P–S, Brazil) for 4 h. The supported catalysts were analyzed by elemental analyses (EDXRF spectrometer from Shimadzu, model EDX 720, Japan) according to a method that has already been described in the literature [22, 23].…”

Section: Methodsmentioning

confidence: 99%

“…The average yield was approximately 60% as calculated gravimetrically. Additional details of the procedure can be found elsewhere [16].…”

Section: Methodsmentioning

confidence: 99%

“…Recently, we found that carbon-supported H 3 PW 12 O 40 could be used as a catalyst in the conversion of D,L-lactic acid to enantioselective blends of PLA [16]. Keggin heteropolyacid (HPA) is an important class of solid acids among which 12-tungstophosphoric acid (H 3 PW 12 O 40 , H 3 PW) is particularly important because it can be used in acid catalysis for greener processes [17, 18, 19, 20, 21].…”

Section: Introductionmentioning

confidence: 99%

“…Different loadings of H 3 PW/C and calcination temperatures have been studied to optimize PLA formation. Precise experimental conditions have been developed and have resulted in the formation of PLA blends with a high level of enantiomeric excess (85%) [16].…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Preparation of PLA blends by polycondensation of D,L-lactic acid using supported 12-tungstophosphoric acid as a heterogeneous catalyst

Chafran

Paiva

França

et al. 2019

Heliyon

Self Cite

View full text Add to dashboard Cite

Poly(lactic acid) (PLA) is a significant polymer that is based on renewable biomass resources. The production of PLA by polycondensation using heterogeneous catalysis is a focus for sustainable and economical processes. A series of samples comprising 12-tungstophosphoric acid (H 3 PW) supported on activated carbon, silica, and alumina induced the catalytic polymerization of D,L-lactic acid to form blends of PLA. The catalysts were characterized by multiple techniques to confirm the integrity of the Keggin anion as well as the acidity, which is the key property for relating structure to activity. The best reaction conditions were established for H 3 PW/C and tested for the other supported catalysts. The obtained polymer was a blend that was characterized as an enantiomeric excess (ee) of as much as 95% L-PLA (PLLA) with a mass average molar mass ( M w ) of approximately 14,900 daltons. The role of H 3 PW in these polymerizations was demonstrated, i.e., without the Keggin acid, only oligomeric units ( M w < 10,000 daltons) could be obtained. Additionally, inverse relationships between the M w of PLA and the enthalpy (–Δ H ) of the strongest sites of the catalysts were distinguished, i.e., PLA Mw-H3PW/C > PLA Mw-H3PW/Al2O3 > PLA Mw-H3PW/SiO2 , whereas the acidity (–Δ H ) order was as follows: H 3 PW/SiO 2 > H 3 PW/Al 2 O 3 > H 3 PW/C. These findings could be attributed to the correct tuning of strength and the accessibility of the sites to produce longer polymeric chains.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

“…The average yield was approximately 60% as calculated gravimetrically. Additional details of the procedure can be found elsewhere [16].…”

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Preparation of PLA blends by polycondensation of D,L-lactic acid using supported 12-tungstophosphoric acid as a heterogeneous catalyst

Chafran

Paiva

França

et al. 2019

Heliyon

Self Cite

View full text Add to dashboard Cite

show abstract

Evaluation of polyaniline protonation onPLGApolycondensation viaSty‐DVB/Pani catalyst

Gomes

Moura

Chaves

et al. 2023

Polymer Engineering & Sci

View full text Add to dashboard Cite

This study presents a method to polymerize aniline in styrene‐divinylbenzene copolymer pores using benzoyl peroxide as an initiator. The composites are sulfonated, impregnated with tin oxide (IV) and used as heterogeneous catalysts in the direct polycondensation synthesis of PLGA. Evaluation of parameters such as molar proportion, temperature, time, quantity and type of catalyst were carried out. The characterization of composites and PLGA's were performed by: elemental analysis, DRX, FTIR, nitrogen adsorption–desorption, Brønsted acid site determination, SEM, ICP/OES, and inherent viscosity. The polyaniline deprotonation before thermal treatment enhances crosslinking, increasing surface area and stability of the porous structure. The composite acts as a catalyst, increasing PLGA molar mass, reducing oxidation and tin contamination. The process has several advantages like PLGA production without solvent contamination, lower tin content, and no high‐cost cyclic dimmers use. So far, the results show promising catalytic performance of the developed composite.

show abstract

Green Catalysts in the Synthesis of Biopolymers and Biomaterials

2022

View full text Add to dashboard Cite

The modernization processes of the chemical industry over the last few years reinforce concerns about the sustainable use of natural resources and the synthesis of solvent‐free and low toxicity products. Additionally, the development of new catalysts capable of minimizing or even eliminating hazardous substances commonly used in the chemical industry has received increasing attention in the academic and industrial environments within the context of Green Chemistry, based on the search for products and processes capable of reducing or even eliminating the use of hazardous substances. This need becomes even greater when it comes to the synthesis and modification of biopolymers with great applicability in the biomedical field such as poly(lactic acid) (PLA), poly(glycolic acid) (PGA), poly(caprolactone) (PCL) in addition to acrylate‐based polymers. The present review aims to discuss the major classes of green catalysts and biocatalysts, their main characteristics, and different synthetic routes. To emphasize the importance of green catalysts in the biomedical industry, different synthetic routes are discussed to obtain biopolymers and biomaterials whose different degradation products have low or no environmental impact, and whose yield rate, degradability, and selectivity are controlled by presence of a catalyst.

show abstract

Synthesis of poly(lactic acid) by heterogeneous acid catalysis from d,l-lactic acid

Cited by 19 publications

References 40 publications

Preparation of PLA blends by polycondensation of D,L-lactic acid using supported 12-tungstophosphoric acid as a heterogeneous catalyst

Preparation of PLA blends by polycondensation of D,L-lactic acid using supported 12-tungstophosphoric acid as a heterogeneous catalyst

Evaluation of polyaniline protonation onPLGApolycondensation viaSty‐DVB/Pani catalyst

Green Catalysts in the Synthesis of Biopolymers and Biomaterials

Contact Info

Product

Resources

About