Triacetin Research Articles

Neat lipase-catalysed kinetic resolution of racemic 1-phenylethanol and a straightforward modelling of the reaction

Enzymatic kinetic resolution of racemic 1-phenylethanol catalysed by immobilized Candida antarctica lipase B was investigated in a neat system at the temperature range of 30–70 °C. Synthetic triglycerides, namely glycerol triacetate and glycerol tributyrate, were applied as the esterification agents. Both esterification agents were efficient regarding to the enantioselectivity (>1000). Initial rate of reaction and the kinetic constants were influenced by the applied esterification agent significantly. A detailed modelling approach is presented and verified in the temperature range on 30–60 °C for the tributyrin system.

Increasing acetyl-CoA metabolism attenuates injury and alters spinal cord lipid content in mice subjected to experimental autoimmune encephalomyelitis.

Acetate supplementation increases brain acetyl-CoA metabolism, alters histone and non-histone protein acetylation, increases brain energy reserves, and is anti-inflammatory and neuroprotective in rat models of neuroinflammation and neuroborreliosis. To determine the impact acetate supplementation has on a mouse model of multiple sclerosis, we quantified the effect treatment had on injury progression, spinal cord lipid content, phospholipase levels, and myelin structure in mice subjected to experimental autoimmune encephalomyelitis (EAE). EAE was induced by inoculating mice with a myelin oligodendrocyte glycoprotein peptide fragment (MOG35-55 ), and acetate supplementation was maintained with 4g/kg glyceryl triacetate by a daily oral gavage. Acetate supplementation prevented the onset of clinical signs in mice subject to EAE compared to control-treated mice. Furthermore, acetate supplementation prevented the loss of spinal cord ethanolamine and choline glycerophospholipid and phosphatidylserine in mice subjected to EAE compared to EAE animals treated with water. Treatment increased saturated and monounsaturated fatty acid levels in phosphatidylserine compared to controls suggesting that acetate was utilized to increase spinal cord fatty acid content. Also, acetate supplementation prevented the loss of spinal cord cholesterol in EAE animals but did not change cholesteryl esters. Treatment significantly increased GD3 and GD1a ganglioside levels in EAE mice when compared to EAE mice treated with water. Treatment returned levels of phosphorylated and non-phosphorylated cytosolic phospholipase A2 (cPLA2 ) levels back to baseline and based on FluoroMyelin™ histochemistry maintained myelin structural characteristics. Overall, these data suggest that acetate supplementation may modulate lipid metabolism in mice subjected to EAE.

Synergistic effect of silver nanoparticle content on the optical and thermo-mechanical properties of poly(l-lactic acid)/glycerol triacetate blends

Monodispersed silver nanoparticles (Ag-NPs) were synthesized by chemical reduction in aqueous medium and transferred in chloroform to be redispersed in the plasticized matrix of poly(l-lactic acid) (PLA) by melt compounding. PLA nanocomposites were prepared using a combination of Ag-NPs in amounts of 0.01, 0.025, 0.05, 0.075 and 0.1% in weight, with 10 pph (parts per hundred) of glycerol triacetate (GTA) to be characterized by UV–Vis and Fourier transformed infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). Optical properties showed that PLA nanocomposites have monodispersed Ag-NPs due to the intense SPR (surface plasmon resonance) absorption band at 414 nm, with a calculated particle size of ~30 nm. The crystallinity is gradually raised at a maximum level (21.1%) compared to the pure PLA (2.3%) and Tg drastically decreased from 61 to 36.8 °C when Ag-NPs are incorporated in the plasticized PLA matrix. These results were consistent with the enhanced elastic modulus in DMA analysis, explained from the viewpoint of a good nanofiller dispersion and crystallization behavior, providing a stable and ordered crystal (α-form) in agreement with FTIR and DSC analysis. Finally, the outcomes indicate a synergistic effect between Ag-NPs and the plasticizer GTA, due to the nucleating effect of the monodispersed Ag-NPs and the mobility chain promoted by the plasticizer in the macromolecular arrangement of the PLA.

Interrogating ultrafast dynamics of a salicylideneaniline derivative within faujasite zeolites

We report on femtosecond (fs) studies of (E)-2-(2-hydroxybenzyliden) amino-4-nitrophenol (HBA-4NP) in dichloromethane (DCM) and triacetin (TAC) solutions, and within NaX and NaY zeolites. In solution, an ultrafast (≤80fs) excited-state intramolecular proton-transfer (ESIPT) reaction produces a keto (K) tautomer, which undergoes a rotational process in ∼4 (DCM) and ∼7ps (TAC) toward the formation of non-emitting structures. Within NaX and NaY, where monomers and aggregates are formed, host-guest and guest-guest interactions play an important role in the ultrafast behaviour of these complexes. These results clearly reflect how nanoconfinement and zeolite composition affect the encapsulated dye photodynamics.

Biodiesel fuel production from algal lipids using supercritical methyl acetate (glycerin-free) technology

Supercritical methyl acetate (SCMA) technology was demonstrated for converting total lipids from Nannochloropsis salina into fatty acid methyl esters (FAMEs) and triacetin (TA). In this non-catalytic process, triacetin is produced instead of glycerin as a side-product during transesterification which is miscible with FAME and can be readily used as biodiesel fuel (BDF). Supercritical carbon-dioxide (SC-CO2), clean and green technology was employed to extract total lipids from algal biomass. The process parameters such as lipid to methyl acetate molar ratio, reaction temperature and reaction time were studied to evaluate their effects on the FAME yield and algal biodiesel fuel yield. Algal lipid characterization and algal biodiesel fuel analysis were carried out using analytical instruments such as FTIR and GC–MS. Thermogravimetric analysis under nitrogen and oxygen environments was performed to examine the thermal and oxidative stability of the algal biodiesel fuel. A micro-elemental analysis (CHNOS) of total algal lipid and biodiesel fuel was performed according to ASTM methods. The fuel properties of algal biodiesel fuel produced were compared with those of the regular diesel and biodiesel American Society for Testing and Materials (ASTM) standards.

Influence of the scale and type of processing tool on plasticization of cellulose acetate

Four processing tools (two twin-screw extruders, one being a mini-extruder, and two mixers) were used to prepare plasticized cellulose acetate with 20 wt% of glycerol triacetate. The goal was to deduce if the scale of the processing tool influences the dispersion of the plasticizer as estimated by the thermal, rheological, and mechanical properties of the obtained materials. The amount of polymer used ranged from 5 g for mini-extruder to a 10 kg/h for pilot-scale extruder. The specific mechanical energy was used to compare the thermal, rheological, and mechanical properties of cellulose acetate obtained with the four processing tools using different processing conditions. The measurement of the glass transition temperature was not able to discriminate the four tools used. Rheology shows differences, not as a function of small or large tools, but in terms of specific mechanical energy. The larger was the tool, the higher were the Young's moduli. This was ascribed to an overall better distribution and dispersion of the plasticizer. However, all variations were small, showing that small laboratory processing machines can prepare thermoplastic compounds with similar properties as pilot scale extruders, at least in what concerns cellulose acetate. POLYM. ENG. SCI., 2016. © 2016 Society of Plastics Engineers

Solubilities and Thermodynamic Properties of Carbon Dioxide in Some Biobased Solvents

Using the isochoric saturation method, solubilities of CO2 in five biobased solvents (BBSs) have been determined at temperatures between 293.15 and 323.15 K with 10 K intervals and pressure scope of (0–600.0) kPa. The BBSs were selected from glyceryl triacetate (GT), glycerol formal (GF), dl-1,2-isopropyli-deneglycerol (GAK), triethyl citrate (TEC), and acetyl triethyl citrate (ATEC). Henry’s constants and thermodynamic properties such as Gibbs free energy, enthalpy, and entropy of dissolution were derived from the solubility data. The gravimetric solubilities of CO2 in BBSs changed with the sequence of GT > ATEC > TEC ≈ GAK > GF. All the dissolution enthalpies were negative at each condition. The dissolution capacities of BBSs for CO2 were further compared with those of several common absorbents as well as ionic liquids. It was shown that they were similar to polyethylene glycol dimethyl ether (NHD) which is an industrial CO2 absorbent.

Immobilization of lipase onto functional cyclomatrix polyphosphazene microspheres

Functional polyphosphazene cyclomatrix microspheres (PMS) containing glucose and dodecyl moieties were utilized for physical adsorption of lipase. In this regard, Candia Rugosa lipase was immobilized onto the above microspheres through physical adsorption, which exhibited catalytic hydrolysis of glycerol triacetate as the model reaction. As observed under transmission electron microscope (TEM) and scanning electron microscope (SEM), the size of all the microspheres ranged from 400nm to 1μm with a mean diameter of 680nm. Zeta potential analysis demonstrated that the microspheres were negatively charged. The influences of buffer pH, substrate concentration and temperature were also studied along with reusability. The obtained results demonstrated that the immobilized lipase on deprotected glycosylated PMS (D-GPMS) showed the best performance and possessed the highest enzymatic loading activity around 1.0884mmolL−1min−1g−1, and retained nearly 50% of its initial activity even after 10 cycles of application. Moreover, the lipase-microsphere complex displayed high pH adaptability from 7 to 9 and temperature stability above 40°C. From the viewpoint of biocompatible PMS support, the GPMS-lipase conjugate have potential applications in field such as food, medicine and environment.

Application conditions for ester cured alkaline phenolic resin sand

Five organic esters with different curing speeds: propylene carbonate (i.e. high-speed ester A); 1, 4-butyrolactone; glycerol triacetate (i.e. medium-speed ester B); glycerol diacetate; dibasic ester (DBE) (i.e. low-speed ester C), were chosen to react with alkaline phenolic resin to analyze the application conditions of ester cured alkaline phenolic resin. The relationships between the curing performances of the resin (including pH value, gel pH value, gel time of resin solution, heat release rate of the curing reaction and tensile strength of the resin sand) and the amount of added organic ester and curing temperature were investigated. The results indicated the following: (1) The optimal added amount of organic ester should be 25wt.%-30wt.% of alkaline phenolic resin and it must be above 20wt.%-50 wt.% of the organic ester hydrolysis amount. (2) High-speed ester A (propylene carbonate) has a higher curing speed than 1, 4-butyrolactone, and they were both used as high-speed esters. Glycerol diacetate is not a high-speed ester in alkaline phenolic resin although it was used as a high-speed ester in ester cured sodium silicate sand; glycerol diacetate and glycerol triacetate can be used as medium-speed esters in alkaline phenolic resin. (3) High-speed ester A, medium-speed ester B (glycerol triacetate) and low-speed ester C (dibasic ester, i.e., DBE) should be used below 15 oC, 35 oC and 50 oC, respectively. High-speed ester A or lowspeed ester C should not be used alone but mixed with medium-speed ester B to improve the strength of the resin sand. (4) There should be a suitable solid content (generally 45wt.%-65wt.% of resin), alkali content (generally 10wt.%-15wt.% of resin) and viscosity of alkaline phenolic resin (generally 50-300 mPa∙s) in the preparation of alkaline phenolic resin. Finally, the technique conditions of alkaline phenolic resin preparation and the application principles of organic ester were discussed.

Plasticizing effect of glyceryl tribenzoate, dipropylene glycol dibenzoate, and glyceryl triacetate on poly(lactic acid)

The aim of this article is to compare the plasticizing effect of different plasticizers on poly(lactic acid) (PLA) including glyceryl tribenzoate (GTB), dipropylene glycol dibenzoate (DPGDB), and glyceryl triacetate (GTA). The chemical structures of plasticizers are characterized by 1H‐nuclear magnetic resonance. PLA is blended with GTA, DPGDB, and GTB at various contents by using a twin screw extruder. Plasticizing effect of three plasticizers are evaluated by comparison of thermal property, storage stability, melt plasticizing coefficient, thermal degradation, and water vapor permeability. This study reveals that PLA/DPGDB exhibits better physical properties than the others do. DPGDB containing ether and ester groups may therefore render good compatibility with PLA. POLYM. ENG. SCI., 56:1399–1406, 2016. © 2016 Society of Plastics Engineers

Effect of glyceryl triacetate on properties of PLA/PBAT blends

Poly lactic acid (PLA)/Poly (butyleneadipate-co-terephthalate)(PBAT) and glyceryl triacetate (GTA) blend were prepared by torque rheometer, and the effect of GTA on thermodynamical performance, mechanical properties and microstructure of PLA/PBAT composites were studied using differential scanning calorimeter(DSC), dynamic mechanical analysis(DMA), universal testing machine, impact testing machine and scanning electron microscope(SEM). After adding GTA, Tg values of the two phases gradually became closer, blends cold crystallization temperature and melting temperature decreased. When with 3 phr GTA, the dispersed phase particle size of PLA/PBAT blend decreased. Mechanics performance test showed that the elongation at break and impact strength of the PLA/PBAT blend was greatly increased with 3 phr GTA, and the elongation at break increased 2.6 times, improved from 17.7% to 64.1%.

Organic/organic mixture separation by using novel ECTFE polymeric pervaporation membranes

Abstract ECTFE polymeric membranes were prepared via thermally induced phase separation (TIPS) technique using N-methyl-2-pyrrolidone as latent solvent and glycerol triacetate, triethyl citrate and adipic acid as plasticizers in order to improve polymer processability. The membranes were characterized by scanning electron microscopy, mechanical and contact angle tests for better evaluate their morphological and surface properties. The affinity and the resistance of the membranes with respect to different organic solvents (i.e. ethanol, methanol, methyl tert-butyl ether, ethyl tert-butyl ether and cyclohexane) were evaluated by means of swelling tests. All the membranes showed excellent solvent resistance (after 72 h) and high affinity to polar solvents, in particular to ethanol, whereas a low affinity to non polar solvents as cyclohexane was observed. Pervaporation (PV) tests by using a binary azeotropic mixture of ethanol and cyclohexane (30.5% w/w and 69.5% w/w) were carried out at different temperatures (30, 40 and 50 °C) and permeate pressures (2, 25 and 45 mbar). In all cases an improvement of the membrane performances, in terms of total flux, was observed by increasing the temperature and/or decreasing the permeate pressure. An improvement of the selectivity was, instead, obtained when both the temperature and the permeate pressure increased. The membranes with triethyl citrate and glycerol triacetate showed higher total flux, 1.7 kg m−2 h−1 and 1.5 kg m−2 h−1, with an ethanol/cyclohexane selectivity of 15 and 16, respectively. The membrane with adipic acid showed lower total flux, 0.45 kg m−2 h−1 of, but exhibited a much higher ethanol/cyclohexane selectivity, 31.

Effect of composite edible coating from gelatin and glycerol triacetate on prolonging shelf life of refrigerated strawberry

Postharvest treatments of strawberries are necessary to maintain high quality of the product for longer periods, to reduce postharvest losses and to add quality value .The ability of three solution of edible films (6%gelatin-6%gelatin with 10% glycerol triacetate - 6%gelatin with 20% glycerol triacetate), to extend the shelf-life of strawberry fruit over 12 days was studied. Strawberries were immersed in the films solutions for 1 minute and after coated were dried at 15 ºC for 24 hours. The strawberries were then kept under refrigeration .The quality of coated and non-coated strawberries was evaluated by weight loss , titratable acidity, total soluble solids and total sugar concentration ,vitamin C and visible decay during over a 12-day storage period. Results showed that the merge of fat material with gelatin films extend shelf-life of strawberries and keep the quality of the strawberries during storage, when compared with control fruits, but it did not delay of visible decay during refrigerated storage.

Preparation and characterization of ECTFE hollow fiber membranes via thermally induced phase separation (TIPS)

Abstract A porous poly (ethylene-chlorotrifluoroethylene) (ECTFE) membrane was prepared and evaluated in this study. Initially, solvent screening revealed diethyl phthalate (DEP) and glycerol triacetate (GTA) as proper solvents for the preparation of homogenous ECTFE solutions with the required properties for fabricating a hollow fiber membrane. The thermodynamic phase diagrams for both systems (ECTFE/DEP and ECTFE/GTA) showed a liquid–liquid (L-L) phase separation region, which is needed for a bicontinuous structure, prior to solid–liquid (S-L) phase separation (polymer crystallization). The ECTFE hollow fiber membranes were prepared by a thermally induced phase separation (TIPS) method using a unary solvent (DEP or GTA). The morphologies of hollow fiber membranes were observed by scanning electron microscopy (SEM) and it was observed that a bicontinuous structure was formed through L-L phase separation. The effect of the solvent types on properties of the prepared membrane such as water permeability and mechanical strength was discussed in detail. Moreover, the spherulite growth rate and crystallization degree were measured to assess the differences in the mechanical properties of the membranes prepared using DEP and GTA. In this study, with a polymer concentration of 20 wt%, the membrane showed a superior water flux and comparable mechanical properties with the ECTFE membranes already reported in published papers. Furthermore, the chemical resistance properties of ECTFE hollow fiber membranes were evaluated using the harsh treatments.

Lipase catalysed conversion of triglycerides to amides in liquid ammonia

AbstractImmobilised lipase B (Candida antarctica lipase B) is, perhaps unexpectedly, catalytically active in liquid ammonia and exhibits chain length selectivity in the ammonolysis of triglycerides. Using glycerol triacetate as the substrate, the ammonolysis of only the first ester linkage is catalysed by the enzyme, whereas for glycerol tributyrate, the cleavage of all three ester groups is catalysed and converted to the corresponding amide. These observations represent the first example of the use of enzymes in pure liquid ammonia, exemplifying both catalysis and selectivity. Glycerol trioleate is relatively stable in liquid ammonia but, with Candida antarctica lipase B present, readily undergoes ammonolysis to give oleamide and glycerol even at 25 °C. There is no enzyme‐catalysed ammonolysis with the native lipase as it is insoluble in liquid ammonia. The solvolysis of triglycerides in liquid ammonia occurs by a stepwise conversion of the triester to diester to monoester to glycerol with one equivalent of carboxylic acid amide produced at each stage. The pseudo first‐order rate constants for each of the three steps of the uncatalysed ammonolysis of triglycerides in liquid ammonia decrease with increasing alkyl chain length in the carboxyl residue as expected from a small steric effect. Copyright © 2016 John Wiley & Sons, Ltd.

Structure and properties of poly(acrylonitrile‐co‐methyl acrylate) membranes prepared via thermally induced phase separation

ABSTRACTPoly(acrylonitrile‐co‐methyl acrylate) [(P(AN‐MA)] microporous membranes were prepared via a thermally induced phase separation (TIPS) process by using γ‐butyrolactone (γ‐BA) and glyceryl triacetate (GTA) as the mixed diluent. The purpose of this work is to investigate the effects of the γ‐BA content, P(AN‐MA) concentration, and cooling rate on the structure and properties of P(AN‐MA) membranes. A lacy structure with high connectivity was formed with 50 wt % γ‐BA, and 50 wt % GTA comprising the mixed diluent. With an increase in the γ‐BA content, the pore structure acquires semi‐closed or completely closed cell‐like morphologies. The different phase separation mechanisms greatly influence the mechanical properties of the P(AN‐MA) membranes. P(AN‐MA) membranes with a lacy structure possess better tensile strength than those with semi‐closed or completely closed cell‐like structures. The membrane pore size grows larger when the TIPS process utilizes a higher γ‐BA content and a lower cooling rate. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43444.

Oral acetate supplementation attenuates N-methyl D-aspartate receptor hypofunction-induced behavioral phenotypes accompanied by restoration of acetyl-histone homeostasis.

Aberrations in cellular acetate-utilization processes leading to global histone hypoacetylation have been implicated in the etiology of neuropsychiatric disorders like schizophrenia. Here, we investigated the role of acetate supplementation in the form of glyceryl triacetate (GTA) for the ability to restore the N-methyl D-aspartate (NMDA) receptor-induced histone hypoacetylation and to ameliorate associated behavioral phenotypes in mice. Taking cues from the studies in SH-SY5Y cells, we monitored acetylation status of specific lysine residues of histones H3 and H4 (H3K9 and H4K8) to determine the impact of oral GTA supplementation in vivo. Mice treated chronically with MK-801 (10days; 0.15mg/kg daily) induced hypoacetylation of H3K9 and H4K8 in the hippocampus. Daily oral supplementation of GTA (2.9g/kg) was able to prevent this MK801-induced hypoacetylation significantly. Though MK-801-stimulated decreases in acetyl-H3K9 and acetyl-H4K8 were found to be associated with ERK1/2 activation, GTA seemed to act independent of this pathway. Simultaneously, GTA administration was able to attenuate the chronic MK-801-induced cognitive behavior phenotypes in elevated plus maze and novel object recognition tests. Not only MK-801, GTA also demonstrated protective effects against behavioral phenotypes generated by another NMDA receptor antagonist, ketamine. Acute (single injection) ketamine-mediated hyperactivity phenotype and chronic (10days treatment) ketamine-induced phenotype of exaggerated immobility in forced swim test were ameliorated by GTA. The signature behavioral phenotypes induced by acute and chronic regimen of NMDA receptor antagonists seemed to be attenuated by GTA. This study thus provides a therapeutic paradigm of using dietary acetate supplement in psychiatric disorders.

Techno-Economic Analysis of Different Plant Configuration for Thermoelectric Cogeneration from Biomass Boiler

Thermoelectric modules integration within biomass boiler for the direct conversion of heat into electricity is a possibility to increase efficiency and to realize a stand-alone biomass boiler. Due to the low conversion efficiency (up to 5%) of commercial thermoelectric modules, the aim of the integration shall not be the electricity production for external power supply, but the energy self-consumption of biomass boiler electric auxiliaries. The paper describes and analyses four different options for the integration of thermoelectric modules within a biomass boiler: in the combustion chamber, in the convective tubes, in the chimney and with a condensing fluid circuit to be realized outside the biomass boiler. Five quantitative and qualitative key performance indicators have been defined to assess how the integration strategy can influence the electric yield of thermoelectric modules, the ease of maintenance, the operation continuity, the need of auxiliaries systems to be added as well as the impact on biomass boiler redesign or retrofit. The analysis shows that the realization of a circuit with a condensing fluid allows reaching the best combination of key performance indicators. On the basis of this result, the paper also shows the preliminary design of a new test facility to test Glycerol Triacetate as condensing fluid to produce electricity by thermoelectric modules.

Functionalized blown films of plasticized polylactic acid/chitin nanocomposite: Preparation and characterization

Bionanocomposite films prepared with melt compounding and film blowing were evaluated for packaging applications. The nanocomposite masterbatch with 75wt.% polylactic acid (PLA), 5wt.% chitin nanocrystals (ChNCs) and 20wt.% glycerol triacetate plasticizer (GTA) was melt compounded and then diluted to 1wt.% ChNCs with PLA and polybutylene adipate-co-terephthalate (PBAT) prior to film blowing. The morphological, mechanical, optical, thermal and barrier properties of the blown nanocomposite films were studied and compared with the reference material without ChNCs. The addition of 1wt.% ChNCs increased the tear strength by 175% and the puncture strength by 300%. Additionally, the small amount of chitin nanocrystals affected the glass transition temperature (Tg), which increased 4°C compared with the reference material and slightly enhanced the films degree of crystallinity. The chitin nanocomposite also had lower fungal activity and lower electrostatic attraction between the film surfaces; leading to easy opening of the plastic bags. The barrier and optical properties as well as the thermal degradation of the films were not significantly influenced by the addition of chitin nanocrystals.

Acetylation of Glycerol over Sulfated Alumina: Reaction Parameter Study and Optimization Using Response Surface Methodology

A highly active and stable SO42–/γ-Al2O3 catalyst was developed, and the catalytic activity was evaluated for esterification of glycerol. The reactions were performed in a batch reactor under reflux conditions. The influence of reaction conditions, such as the reaction temperature, catalyst amount, and acetic acid/glycerol mole ratio, on the product distribution was investigated. The results demonstrated that the 2 M SO42–/γ-Al2O3 catalyst was very active and showed 100% glycerol conversion with 77.4% selectivity of higher esters [glycerol diacetate (DAG) + glycerol triacetate (TAG)] at 95 °C, after 5 h of reaction time in the presence of acetic acid/glycerol mole ratio of 12:1. Further, response surface methodology (RSM) was used for the development of the empirical process model, followed by the optimization of reaction parameters. The optimization process depicted that 76.1% combined selectivity to DAG and TAG can be achieved at complete conversion of glycerol at 108.8 °C in the presence of 0.36 g of c...