Volume 23 (2021): Edizione 4 (December 2021)

New extractive distillation configurations, which use low transition temperature mixtures (LTTMs) as entrainers, have attracted widespread attention among scholars due to their green processes. Furthermore, the design and comparison of different processes can promote the application of new solvents in the future. In this study, two extractive distillation processes, the extractive distillation column (ED) and the extraction dividing wall column (EDW), were selected from previous work. The separation process of acetonitrile (ACN)-water ternary mixtures was studied, and GC3:1(choline chloride/glycolic acid mixture (molar mass 1:3)) and EC2:1((choline chloride/ethylene glycol 1:2 molar mass) were used as entrainers. Minimum consumption energy and the purity of ACN and water were set as the goals, and our sensitivity analysis and economic evaluation results showed that both ED and EDW were effective. As a result, LTTMs can be used in extractive distillation for azeotrope separation.

A series of the terpolymers of poly[(trimethylene terephthalate)-block-(oxytetramethylene)-block-laurolactam] with a variable molar ratio of ether and amide block and constant molecular weights of PA12 = 2000 g/mole and PTMO = 1000 g/mole have been obtained. The influence of changes of these molar ratios on the functional properties and the values of phase change temperatures of the products have been determined. The thermal properties and the phase separation of obtained systems were defined by DSC, DMTA and WAXS methods. The chemical structure of obtained materials was studied by FT-IR and 13C NMR methods. The mechanical and elastic properties of these polymers were evaluated.

Currently, agriculture has shifted to green production, in which the recycling of post-production by-products is a key issue. In the present work, by-products such as pomelos were studied to promote consumption and enhance the value of pomelo. From pomelo material, essential oils extracted from pomelo peels, pectin, and drying pomelo products have been diversified. In the extraction process of essential oils, the hydrodistillation method was applied in conjunction with the response surface method to obtain the optimal conditions of influence factors. These essential oils were quantified as well as determined for components by GC-MS. The pectin recognition process was done by immersion method in HCl acid (pH 2) and the drying process was made with a heat pump dryer under the effects of drying temperature, drying time and wind rate. The results of the essential oil products reached the highest (0.88 ±0.006 g) at the material size of 3 mm, the distillation time of 27 min, and the ratio of raw materials/solvents of 1/12 g/mL. The main components found in pomelo peeling essential oils included limonene (71.768%), γ-terponene (12,847%), α-Phellandrene (2.979%), β-myrcene (2.668%), 1R-α-pinene (2,656%), and β-pinene (1,191%). The pectin content was the highest under the temperature of 90 °C, extraction time of 60 min and ratio/solvent ratio of 1:32 g/mL. Under these extraction conditions, 48% of concentrated pectin content was obtained. Surveying conditions for drying white pomelo peels are capable of reversing: refunded drying pomelos are drying heat pumps in the following conditions: 50 °C drying temperature, the drying time of 90 min, and wind rate of 12 m/s. Product with hardness 309.862 N.

Essential oil extraction technique from mandarin pixie peels by hydro-distillation is optimized by response surface methodology (RSM). Mathematical techniques were used in experimental design to evaluate the impacts of factors that affect the extraction process and improve the yield of the extraction process. A central mixed design based on influencing variables such as water ratio (3–5 mL/g), temperature (110–130 °C) and extraction time (90–150 min) was adopted with essential oil yield as the target function. Correlation analysis of the mathematical regression model showed that the quadratic polynomial model can be used to optimize hydro-distillation of pixie mandarin oil. The results showed that under the optimum extraction conditions, the highest quantity of essential oils was achieved (7.28 mL/100 g materials). In terms of statistical analysis, the significance levels (p-value <0.05) of the model showed that the experimental results had a good impact between factors. The coefficient of determination indicating the match between the experimental value and the predicted value of the model was high (R2>0.9). The chemical composition of the essential oil was analyzed by Gas Chromatography-Mass Spectrometry, revealing the dominance of limonene content (97.667%), which implies that the essential oil of pixie mandarin could be an alternative source of limonene.

Furfuryl mercaptan has the aroma characteristics of coffee. However, it is unstable during storage of coffee brew and roasted coffee. In order to enhance the stability of furfuryl mercaptan, furfuryl mercaptan-β-cyclodextrin inclusion complex was synthesized using the precipitation method in this work. Fourier transform infrared spectroscopy, x-ray diffraction, and thermogravimetric analysis (TG) were used to characterize the resulting products. The interaction of furfuryl mercaptan with β-cyclodextrin was investigated by the molecular mechanics (MM) method. These changes in FTIR and XRD gave supporting evidence for the successful formation of furfuryl mercaptan-β-cyclodextrin inclusion complex. The TG results showed that the formation of furfuryl mercaptan-β-cyclodextrin inclusion complex could improve the thermal stability of furfuryl mercaptan and provide a long-lasting effect. The structure of furfuryl mercaptan-β-cyclodextrin inclusion complex with the minimum energy was obtained by MM2 calculation, and the minimum binding energy was –77.0 kJ mol⁻¹ at –1.96 × 10^{–10 m}.