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Background: Isoamyl hexanoate is a widely used edible spice. In this paper, the process and kinetics of the esterification of hexanoic acid and isoamyl alcohol to isoamyl hexanoate catalyzed by deep eutectic solvents (DESs) were studied. Several kinds of DESs (BTMAC‐zPTSA) were prepared from benzyltrimethylammonium chloride (BTMAC) and p‐toluenesulfonic acid monohydrate (PTSA) with a molar ratio of z. The synthesis process of isoamyl hexanoate was optimized by response surface methodology and artificial neural network. The effects of process conditions such as the kind and load of catalyst, alcohol/acid ratio and reaction temperature were studied. In the temperature range of 338.15 to 368.15 K, BTMAC‐1.2PTSA was selected as the catalyst, and then the kinetic data and chemical equilibrium composition of the esterification of hexanoic acid with isoamyl alcohol were determined. Results: After optimizing the synthesis process of isoamyl hexanoate using response surface methodology and artificial neural network, the conversion rate of hexanoic acid increased to 92.15%. The esterification reaction kinetics were described using a pseudo‐homogeneous model based on activity, with an average relative deviation of 1.9% and activation energy of 25.79 kJ mol−1. The catalytic performance of catalyst BTMAC‐1.2PTSA remains good after five cycles of use. Conclusion: The established kinetic model has a good predictive effect on the kinetic data for the synthesis of isoamyl hexanoate. The catalyst BTMAC‐1.2PTSA has good stability and recyclability, and has the potential to replace traditional catalysts in the production of isoamyl hexanoate. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

In this work, the kinetics of the polyvinyl butyral (PVB) synthesis reaction catalyzed by the deep eutectic solvents (DESs) at the low‐temperature stage was studied to control the particle size of PVB resin and optimize its synthesis process. The effects of stirring speed, the concentration of polyvinyl alcohol (PVA), catalyst dosage, and temperature on the synthesis reaction of PVB were investigated. The data obtained from kinetic experiments at 283.15–298.15 K were fitted with the shrinking core models, and the results showed that the model controlled by internal diffusion fitted well with the experimental data. The internal diffusion coefficient, DA, of n‐butanal in the product layer was further calculated by the obtained model parameters, and it was applied to predict the synthesis reaction of PVB at different concentrations of n‐butanal. The results indicated that the shrinking core model controlled by internal diffusion is suitable to describe the kinetics of the PVB synthesis reaction. DES played a dual role in catalysis and dispersion in the synthesis of PVB, and it was a green catalyst with good potential for PVB industrial applications. [ABSTRACT FROM AUTHOR]

Reactive polyurethane hot melt adhesives (HMPURs) containing a blend of polyester and polycarbonate diols can typically exhibit balanced performance, such as bonding properties, tensile strength, and heat resistance. Two series of HMPURs made from poly 1,4-butylene adipate or sebacic acid (SeA)-based polyester diols with different molecular weights were prepared and investigated. Increasing the molecular weight of the SeA-based polyester diols was found to significantly improve their mechanical properties and lap shear strengths. Moreover, the HMPURs made from SeA-based polyester diol exhibited better performances than those made from poly 1,4-butylene adipate. Also, the HMPURs were more suitable for bonding on PC substrate. [ABSTRACT FROM AUTHOR]

This work studied the physical properties of three deep eutectic solvents (DESs) and their catalytic activity in the esterification of palmitic acid and ethanol. Three types of deep eutectic solvents (DESs) were successfully prepared using p-toluene sulfonic acid monohydrate (PTSA) as hydrogen bond donor (HBD) with dodecyl trimethyl ammonium chloride (DTAC), tetradecyl trimethyl ammonium chloride (TTAC) and octadecyl trimethyl ammonium chloride (OTAC) as hydrogen bond acceptor (HBA). The freezing points of DESs were measured in the range of 50%–80% HBD mole percentage, and the composition of DTAC-PTSA, TTAC-PTSA and OTAC-PTSA at the eutectic point (the lowest freezing points) was determined respectively (DES1, DES2 and DES3). The physical properties (density, refractive index, dynamic viscosity, conductivity and pH value) of DES1∼DES3 were studied respectively in the temperature range of 298.15 K to 343.15 K. The results showed that dynamic viscosity, conductivity, density and refractive index all change approximately regularly with the increase of temperature, while pH value remains almost constant when the temperature exceeds 325 K. The catalytic ability of the three DESs in the esterification reaction of palmitic acid and ethanol was investigated, and DES2 was selected as the catalyst for subsequent experiments. The effects of temperature, acid-ethanol molar ratio, catalyst dosage and reaction time on esterification reaction were further studied, and DES' recyclability was also tested. The results obtained showed the great potential of DES in catalytic applications. [ABSTRACT FROM AUTHOR]

The kinetics for hydrolysis of isoamyl DL‐lactate over cation‐exchange resin NKC‐9 was investigated in this paper, which was the prerequisite for a proper design of reactive distillation processes. The effects of mass transfer resistance, temperature, catalyst dosage, and the molar ratio of water to isoamyl DL‐lactate on conversion of isoamyl DL‐lactate were evaluated. The pseudo‐homogeneous (PH), Eley‐Rideal (ER), and Langmuir‐Hinshelwood (LH) models were then utilized to correlate the data obtained from experiments. Activities were used in the kinetics instead of the mole fractions because the reactants and products were not ideal. The activity coefficients were estimated by UNIFAC. It was demonstrated that the PH model was the best one to describe the hydrolysis of isoamyl DL‐lactate. The standard enthalpy was 5.46 kJ · mol−1 and the activation energy was 59.71 kJ · mol−1. Finally, the thermal stability and reusability of NKC‐9 were also tested. [ABSTRACT FROM AUTHOR]

The isothermal crystallization kinetics and melting behaviors after isothermal crystallization of poly(buty-lene terephthalate) (PBT) and poly(butylene terephtha-late-co-fumarate) (PBTF) containing 95/5, 90/10, and 80/20 molar ratios of terephthalic acid/fumaric acid were investigated by differential scanning calorimetry. The equilibrium melting temperatures of these polymers were estimated by Hoffman-Weeks equation. So far as the crystallization kinetics was concerned, the Avrami equation was applied and the values of the exponent n for all these polymers are in the range of 2.50-2.96, indicating that the addition of fumarate does not affect the geometric dimension of PBT crystal growth. Crystallization activation energy (ΔE) and nucleation constant ([K.sub.g]) of PBTF copolymers are higher than that of PBT homopolymer, suggesting that the introduction of fumarate hinders the crystallization of PBT in PBTF. POLYM. ENG. SCI., 53:482-490, 2013. ©2012 Society of Plastics Engineers, INTRODUCTION Poly(butylene terephthalate) (PBT) exhibits excellent thermal and mechanical properties, and high chemical resistance, and is widely used in many industrial application as thermoplastic engineering materials. In order to broaden [...]

The physical solubilities of terephthalic acid (TPA) in the reaction system oligomeric bishydroxybutyl terephthalates--1,4-butanediol (BD) are measured using an analytic method from 449 to 507 K. The reaction system is obtained by transesterification of dimethyl terephthalate and excess BD. These results are fitted with the solubility model based on the Margules equation, and the average deviation of the model is 1.20%; the fusion enthalpies Δ[H.sub.fus] of TPA and infinite-dilution activity coefficients [γ.sub.2.sup.∞] in the system are obtained by regressing of the experimental data. In addition, synthetic method is chosen to determine the total solubility which is complicated by chemical reaction, the results indicate that the chemical reaction start at 452-472 K. POLYM. ENG. SCI., 49:819-823, 2009. [C] 2009 Society of Plastics Engineers, INTRODUCTION Terephthalic acid (TPA) is primarily used in the manufacture and production of various polyester (1), such as poly(butylene terephthalate) (PBT) which is a widely used industrial plastic. PBT has [...]