Response surface methodology for optimization studies of hydro-distillation of essential oil from pixie mandarin (Citrus reticulata Blanco) peels

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.

Process of separating acetonitrile and water using LTTMs as entrainer

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.

Product diversification from pomelo peel. Essential oil, Pectin and semi-dried pomelo peel

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.

Formation and characterization of furfuryl mercaptan-β-cyclodextrin inclusion complex and its thermal release characteristics

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.

Synthesis and mechanical and thermal properties of multiblock terpoly(ester-ether-amide) thermoplastic elastomers with variable mole ratio of ether and amide block

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.

Effect of chemical modification of hydrodistillation on yield, composition and biological activity of Rosmarinus officinalis essential oil

Studies on the chemical modifications of Rosmarinus officinalis essential oil hydrodistillation process (HD) by using 5% citric acid (CA-HD) and 5% trisodium citrate (TSC-HD) as a water phase were performed. Composition of essential oils obtained in conventional and modified conditions was analyzed by gas chromatography with mass selective detector method (GC-MS) and compared. Antioxidant activity of all essential oils was determined spectrophotometrically by using DPPH radical scavenging method. It was found that applied modifications of hydrodistillation process enhanced yields and antioxidant activity and the best results were obtained using 5% citric acid as a modifier. Effect of this modification on fungicidal activity of essential oils against 8 various fungi strains (Alternaria alternata, Botrytis cinerea, Fusarium culmorum, Phythophtora cactorum, Rhizoctonia solani, Phythophtora infestans, Sclerotinia sclerotiorum and Ascosphaera apis) was also determined and in most cases enhanced activity was observed.

Heat effects in the reaction of sulfuric acid with ilmenites influenced by initial temperature and acid concentration

The influence of temperature and sulfuric acid concentration on the enthalpy and the rate of heat release during the reaction of Norwegian and Australian ilmenites with sulfuric acid was determined. The experimental results obtained from calorimetric measurements were compared with theoretical calculations based on the oxide composition and the phase composition of the raw material. Experimentally determined heat of reaction for Norwegian ilmenite (900–940 kJ/kg) and Australian ilmenite (800–840 kJ/kg) showed good agreement with theoretical calculations based on the phase composition of the raw material. It was found that the enthalpy of ilmenites decomposition reaction does not depend on the concentration of sulfuric acid in the concentration range from 83% to 93%. It was also demonstrated that the temperature and concentration of sulfuric acid have a significant impact on the thermokinetics of the decomposition process, increasing the value of the average rate of temperature change.

Thermodynamic analysis on disproportionation process of cyclohexylamine to dicyclohexylamine

This work deals with a study of the effect of temperature on the cyclohexylamine disproportionation to dicyclohexylamine, conjointly with the thermodynamic analysis of this process. The laboratory experiments were carried out in a glass tubular continuous-flow reactor in a gaseous phase at the reaction temperature 433–463 K over a nickel catalyst. The results show, that the temperature has a trifling effect on equilibrium conversion of cyclohexylamine. However, temperature affects the formation of hydrocarbons, benzene and cyclohexane, and dehydrogenation products of dicyclohexylamine, i.e. N-cyclohexylidenecyclohexanamine and N-phenylcyclohexylamine. The latter one is the dominant product of dicyclohexylamine dehydrogenation. The disproportionation of cyclohexylamine has slightly exothermic character. At the experimental reaction temperature range, the cyclohexylamine disproportionation is spontaneous reaction and other reactions of this process are non-spontaneous.

Reinvestigations of the Li2O–Al2O3 system. Part I: LiAlO2 and Li3AlO3

Reinvestigations of the Li2O–Al2O3 system focused on the synthesis and properties of LiAlO2 and Li3AlO3 phases have been performed with the help of XRD and IR measuring techniques and Li2CO3, LiOH·H2O, Al2O3-sl., α-Al2O3, Al(NO3)3·9H2O and boehmite as reactants. Results of investigations have shown the formation of α-, β-, and γ- polymorphs of LiAlO2. It was found that only the use of LiOH·H2O as a reactant yields to β-LiAlO2 as a reaction product. On the other hand, it was proved that Li3AlO3 does not form in the Li2O–Al2O3 system. A new method for the synthesis of α-LiAlO2 was developed, consisting in grinding the mixture of Li2CO3 and Al(NO3)3·9H2O and heating the obtained paste at the temperature range of 400–600 °C. The IR spectroscopy was used to characterize obtained phases.

Kinetic Study on the Preparation of Aluminum Fluoride Based on Fluosilicic Acid

Reasonable mathematical derivation and mechanism model in the process of producing aluminum fluoride by fluosilicic acid is the key to the industrial treatment of fluorine resources in the tail gas of phosphate ore. In this work, aluminum fluoride was generated directly by fluosilicic acid to extract fluorine from the tail gas of phosphate rock. The uncreated-core model dominated by interfacial reaction and the uncreated-core model dominated by internal diffusion-reaction were then respectively utilized to describe the reaction kinetics of the generation of aluminum fluoride. The result showed that the uncreated-core model was dominated by interface reaction and internal diffusion, the apparent reaction order n = 1, and the activation energy Ea = 30.8632 kJ . mol–1. Product characterization and kinetic analysis were employed to deduce the reaction mechanism of preparing aluminum fluoride. The theoretical basis for the low-cost recycling of fluorine resources in the tail gas of industrial phosphate ore was provided in this work.