Sulfonated graphene as highly efficient and reusable acid carbocatalyst for the synthesis of ester plasticizers

Garg, Bhaskar; Bisht, Tanuja; Ling, Yong‐Chien

doi:10.1039/c4ra11205a

Cited by 52 publications

(38 citation statements)

References 60 publications

(33 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…59 Chemical shifts assigned to the ester and carboxylic acid carbonyl carbons of CNC citrate moieties are at 172.1 ppm and 174.3 ppm, respectively. 59,60 Methylene (C13) and methine (C14) 13 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 carbonyl carbons characteristically have long relaxation times, as well as chemical shift anisotropy (CSA) effects. 64 NMR also did not show the presence of anhydride peaks for citrate or malic CNCs, further providing evidence that cross-linking did not occur.…”

Section: Characterization Of Modificationmentioning

confidence: 99%

Concurrent Cellulose Hydrolysis and Esterification to Prepare a Surface-Modified Cellulose Nanocrystal Decorated with Carboxylic Acid Moieties

Spinella

Maiorana

Qian

et al. 2016

ACS Sustainable Chem. Eng.

168

110

View full text Add to dashboard Cite

Cellulose nanocrystals (CNCs) were modified with natural di-and tricarboxylic acids using two concurrent acid-catalyzed reactions including hydrolysis of amorphous cellulose segments and Fischer esterification, resulting in the introduction of free carboxylic acid functionality onto CNC surfaces. CNC esterification was characterized by Fourier Transform Infrared Spectroscopy, 13 C solid state magic-angle spinning (MAS) and conductometric titration experiments. Average degree of substitution values for malonate, malate, and citrate CNCs are 0.16, 0.22 and 0.18, respectively. Despite differences in organic acid pKa, optimal HCl cocatalyst concentrations were similar for malonic, malic and citric acids. After isolation of modified CNCs, residual cellulose co-products were identified that are similar to microcrystalline cellulose based on SEM and XRD analysis. As proof of concept, recycling experiments were carried to increase the yield of citrate CNCs. The by-product was then recycled by subsequent citric acid/HCl treatments that resulted in 55% total yield of citrate CNCs.The crystallinity, morphology, and substitution of citrate CNCs from recycled cellulose coproduct is similar to modified citrate CNCs formed in the first reaction cycle. Thermal stability of all modified CNCs under air and nitrogen resulted in T 10% and T 50% values above 256 °C and 323 °C, respectively. Thus, they can be used for melt-processing operations performed at moderately high temperatures without thermal decomposition. Nanocomposites of polyvinyl alcohol with modified CNCs (1 wt% malonate-, malate-, citrate and unmodified CNCs) wereprepared. An increase in the thermal decomposition temperature by almost 40 °C was obtained for PVOH-citrate modified CNC nanocomposites.Furthermore, since TGA determined weight loss up to 150°C is attributed to loss of bound water, this provides a tool to determine CNC water affinity. By 150°C, the weight loss of modified and non-modified CNCs is 6% and 2%, respectively. Consequently, modified CNCs with surface carboxylate groups have higher water affinity than non-modified CNCs. Moreover, significant differences in the thermal stability are observed as a function of the di-or triacid used for CNC modification. Based on the peaks of the derivative thermogravimetric curve (DTG, T 50% ), modified CNCs have the following thermal stability: malonate = HCl > malate > citrate CNCs.Corresponding values for T 50% are 366°C, 365°C, 350°C and 345°C, respectively. The amount of residual char at 600°C for HCl, malonate, malate and citrate CNCs is 8, 13, 16 and 20%, respectively. Hence, it follows that increasing the T 50% for di-and tri-acid modified CNCs results in correspondingly lower char formation. Increased char amounts is likely due to CNC functionalizations that lead to relatively larger number of cross-linking events at elevated temperatures.Since the exclusion of air during melt processing is generally not practical, the effect of CNC modification on thermal stability in air was also determined and the correspo...

show abstract

Section: Characterization Of Modificationmentioning

confidence: 99%

Concurrent Cellulose Hydrolysis and Esterification to Prepare a Surface-Modified Cellulose Nanocrystal Decorated with Carboxylic Acid Moieties

Spinella

Maiorana

Qian

et al. 2016

ACS Sustainable Chem. Eng.

168

110

View full text Add to dashboard Cite

show abstract

“…Moreover, petroleum shortages have encouraged research on chemical products obtained from renewable resources. As a result, there is growing interest in the use of natural‐based renewable plasticizers that have low toxicity for the replacement of petroleum‐based plasticizers . Hence, it is important to explore renewable plasticizers having good flame retardancy and thermal stability.…”

Section: Introductionmentioning

confidence: 99%

“…As a result, there is growing interest in the use of natural-based renewable plasticizers that have low toxicity for the replacement of petroleum-based plasticizers. [13][14][15][16][17][18][19] Hence, it is important to explore renewable plasticizers having good flame retardancy and thermal stability.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and application of a novel cardanol‐based plasticizer as secondary or main plasticizer for poly(vinyl chloride)

Chen

Nie

Jiang

2018

Polymer International

View full text Add to dashboard Cite

A novel plasticizer based on cardanol, hydrogenated cardanol glycidyl ether acetic ester containing phosphaphenanthrene group (HCGEP), was prepared and incorporated into poly(vinyl chloride) (PVC) for the first time. The molecular structure was characterized with Fourier transform infrared and 1H NMR spectroscopies. The thermal degradation behavior and flame retardant performance of PVC films with HCGEP as secondary or main plasticizer were investigated using thermogravimetric analysis, combustion tests, limiting oxygen index tests and morphological analysis of residues. Furthermore, the mechanical properties of PVC films were examined based on the results of tensile testing. The results were compared to those of the petroleum‐based plasticizer dioctyl phthalate. With the substitution of dioctyl phthalate with HCGEP, PVC films exhibited high thermal stability and better flame retardant performance. The tensile test results showed that the addition of HCGEP could endow PVC resin with well‐balanced properties of flexibility, strength and hardness. © 2017 Society of Chemical Industry

show abstract

“…Consequently, plasticizers have become the most consumable additives in PVC. [12][13][14][15][16] Currently, there is growing interest in the research and use of natural-based plasticizers which are characterized by low toxicity and low migration levels. 4 However, in recent years, phthalates have been criticized for their potentially toxic effects on human health and environmental impact.…”

Section: Introductionmentioning

confidence: 99%

“…During the last decade, the worldwide production of plasticizers was around 5 million tons per year, 3 among which phthalates play an important role and account for more than 80% due to their good performance and low cost. [17][18][19][20] As the plastics industry and environmental awareness continues to grow, there is an urgent and unmet need to develop new natural plasticizers with improved properties and cost competitiveness. [5][6][7][8][9][10] For this reason, some countries have implemented restrictive regulations regarding the use of phthalates in exible PVC products, especially the products used by children.…”

Section: Introductionmentioning

confidence: 99%

A novel biobased plasticizer of epoxidized cardanol glycidyl ether: synthesis and application in soft poly(vinyl chloride) films

et al. 2015

View full text Add to dashboard Cite

A novel plasticizer derived from cardanol, and epoxied cardanol glycidyl ether (ECGE), was synthesized and characterized by 1 H-NMR and 13 C-NMR. The effects of ECGE combined with the commercial plasticizer dioctyl phthalate (DOP), in soft poly(vinyl chloride) (PVC) films, were studied. The mechanical properties of PVC films showed both tensile strength and percent elongation increases with increasing ECGE content. Thermogravimetric analysis (TGA) was performed to characterize the thermal stabilities of the plasticized samples and showed the stability of films increased on increasing the content of ECGE. The properties of volatility, extraction, and exudation resistance of plasticizers were tested and analysis by means of solubility parameters as reported in the literature suggests the ECGE has similar or higher stability for these properties than DOP. FTIR analysis of the films also revealed that ECGE interacted with PVC. Due to its inherent chemical backbone and the modified epoxy groups, ECGE properly balanced the properties and improved the performance of PVC films compared with the neat DOP plasticizer.

show abstract

Sulfonated graphene as highly efficient and reusable acid carbocatalyst for the synthesis of ester plasticizers

Cited by 52 publications

References 60 publications

Concurrent Cellulose Hydrolysis and Esterification to Prepare a Surface-Modified Cellulose Nanocrystal Decorated with Carboxylic Acid Moieties

Concurrent Cellulose Hydrolysis and Esterification to Prepare a Surface-Modified Cellulose Nanocrystal Decorated with Carboxylic Acid Moieties

Synthesis and application of a novel cardanol‐based plasticizer as secondary or main plasticizer for poly(vinyl chloride)

A novel biobased plasticizer of epoxidized cardanol glycidyl ether: synthesis and application in soft poly(vinyl chloride) films

Contact Info

Product

Resources

About