Effect of Must Hyperoxygenation on Sensory Expression and Chemical Composition of the Resulting Wines

This paper evaluates the effect of must hyperoxygenation on final wine. Lower concentrations of caftaric acid (0.29 mg·L−1), coutaric acid (1.37 mg·L−1) and Catechin (0.86 mg·L−1) were observed in hyperoxygenated must in contrast to control must (caftaric acid 32.78 mg·L−1, coutaric acid 5.01 mg·L−1 and Catechin 4.45 mg·L−1). In the final wine, hydroxybenzoic acids were found in higher concentrations in the control variant (gallic acid 2.58 mg·L−1, protocatechuic acid 1.02 mg·L−1, vanillic acid 2.05 mg·L−1, syringic acid 2.10 mg·L−1) than in the hyperoxygenated variant (2.01 mg·L−1, 0.86 mg·L−1, 0.98 mg·L−1 and 1.50 mg·L−1 respectively). Higher concentrations of total flavanols (2 mg·L−1 in hyperoxygenated must and 21 mg·L−1 in control must; 7.5 mg·L−1 in hyperoxygenated wine and 19.8 mg·L−1 in control wine) and polyphenols (97 mg·L−1 in hyperoxygenated must and 249 mg·L−1 in control must; 171 mg·L−1 in hyperoxygenated wine and 240 mg·L−1 in control wine) were found in both the must and the control wine. A total of 24 volatiles were determined using gas chromatography mass spectrometry. Statistical differences were achieved for isobutyl alcohol (26.33 mg·L−1 in control wine and 32.84 mg·L−1 in hyperoxygenated wine), or 1-propanol (7.28 mg·L−1 in control wine and 8.51 mg·L−1 in hyperoxygenated wine), while esters such as isoamyl acetate (1534.41 µg·L−1 in control wine and 698.67 µg·L−1 in hyperoxygenated wine), 1-hexyl acetate (136.32 µg·L−1 in control wine and 71.67 µg·L−1 in hyperoxygenated wine) and isobutyl acetate (73.88 µg·L−1 in control wine and 37.27 µg·L−1 in hyperoxygenated wine) had a statistically lower concentration.

POLYDENTATE ADSORBENT BASED ON LINEN CELLULOSE MODIFIED BY HYPERBRANCHED POLYESTER POLYBENZOYLTHIOCARBAMATE

A highly efficient hybrid adsorbent based on an industrially available, biodegradable, non-toxic linencellulose modified with hyperbranched polyesterpolybenzoylthiocarbamate has been synthesized.The synthesis was carried out using as a linkertoluene diisocyanate.The second-generation hyperbranched polyesterpolybenzoylthiocarbamate according to 1H, 13C NMR and IR spectroscopy contains 8 terminal benzoylthiocarbamate and 8 hydroxyl groups.In the first stage, the reaction of toluene diisociant with linen cellulose was carried out. By potentiometric titration, the content of toluene diisociant was found to be 27%. Then, hyperbranched polyesterpolybenzoylthiocarbamate was added to the modified linen cellulose. The content of hyperbranched polymer in cellulose, determined by the weight method, is 5%. Unreacted isocyanate groups are neutralized with isobutyl alcohol. The structure of the hybrid material is proven by IR spectroscopy. The adsorption properties of the polydentate adsorbent were studied with respect to Cu(II) ions. It was found that the adsorption capacity of the adsorbent is 6.93 mg/g. Using DSC and TGA analysis, the temperature characteristics, thermal effects, and mass loss of the obtained polydentate compound and its complexes were determined.It was shown that in an acidic medium at pH 3-4, desorption of Cu (II) and Co (II) ions occurs with the regeneration of a hybrid adsorbent.

On the role of higher alcohols in the characterization of cachaça

There is a growing interest in chemical markers for the identification and certification of cachaça as a cane spirit produced in Brazil. It is known that the higher alcohols that are usually analyzed (propyl alcohol, Isobutyl alcohol and isoamyl alcohol) occur in all alcoholic beverages (fermented and distilled), but the relative proportions can vary markedly according to the peculiarities of the raw material and the production process. In this work, the contents of higher alcohols in 300 samples of alembic cachaça were compared, 220 from the state of Minas Gerais and 80 from other states, as well as three samples of industrial cachaça and 14 samples of whiskeys of various brands. The typical range of total higher alcohols in cachaça was 180-360 mg/100 mL ethanol. Cachaça containing higher alcohol concentrations greater than 360 mg/100 mL ethanol do not comply with Brazilian legislation. However, cachaças with higher alcohols concentrations below 180 mg/100 mL ethanol, as was found in one of the industrial cachaças, signify adulteration, for example, by mixing with fuel alcohol. The C4/C5 ratio varied less than the C3/C5 ratio, being consistently within the range of 0.20-0.50. In the whiskeys analyzed, the concentrations of higher alcohols were in the range of 160 and 270 mg/100 mL. Therefore, this parameter would not assist in differentiating between cachaça and whiskey. But the C4/C5 ratio was consistently different, being always greater than 0.50 for the whiskeys. Thus, the routine analysis of higher alcohols provides useful information both for tracking possible fraud and for assessments related to the identity or origin of cachaça.

Simultaneous determination of acetaldehyde, ethyl acetate, methanol, iso butanol, and iso almyacol concentrations in white alcol in some areas in Hai Duong province in 2018 - 2019

The research has developed a method for simultaneous determination of acetaldehyde, ethyl acetate, methanol, isobutyl alcohol, isoamyl alcohol in white alcohol. Validation results show that the method has satisfactory accuracy with recovery in the range of 105 - 108%, repeatability RSD < 1.57%, detection limit below 3 mg/L for all compounds. Proficiency test results in 2020 were satisfactory with Z-scores of all substances below 2. The method has been applied to analyze 200 distilled alcohol samples and 50 blended alcohol samples taken in Hai Duong city during the period from 2018 to 2020. Three of 200 distilled alcohol samples have the methanol content higher than the maximum limit. The relationship between methanol content in proportion to content of acetaldehyde, ethyl acetate, isobutyl alcohol, and isoamyl alcohol in the same sample has been evaluated to distinguish between blended alcohol and distilled alcohol.

Xác định đồng thời hàm lượng acetaldehyde, ethyl acetat, methanol, iso-butanol, iso-almycacol trong rượu trắng ở một số địa bàn tỉnh Hải Dương năm 2018-2020

Nghiên cứu đã phát triển phương pháp xác định đồng thời acetaldehyde, ethyl acetate, methanol, iso-butyl alcohol, isoamyl alcohol trong rượu trắng. Kết quả thẩm định cho thấy phương pháp có độ chính xác đạt yêu cầu với độ thu hồi trong khoảng từ 105 - 108%, độ lặp lại RSD% < 1,57%, giới hạn phát hiện thấp hơn 3,0 mg/L. Kết quả thử nghiệm thành thạo năm 2020 đạt yêu cầu với giá trị Z-score cho các chất đều dưới 2,0. Phương pháp đã được ứng dụng để phân tích 200 mẫu rượu trắng chưng cất và 50 mẫu rượu pha chế được lấy trên địa bàn thành phố Hải Dương trong thời gian từ 2018 đến 2020. Có 03/200 mẫu rượu trắng pha chế có hàm lượng methanol vượt giới hạn cho phép. Dựa vào tỷ lệ giữa hàm lượng các chất acetaldehyde, ethyl acetate, isobutyl alcohol, isoamyl alcohol so với hàm lượng methanol trong cùng một mẫu, có thể sơ bộ đánh giá phân biệt rượu trắng pha chế và rượu trắng chưng cất.

Energy saving in the extractive distillation of isobutyl alcohol–isobutyl acetate with n-butyl propionate

Objectives. Determination of the effectiveness of using various types of heat pumps in the extractive distillation of an isobutyl alcohol–isobutyl acetate mixture with n-butyl propionate as the entrainer.Methods. As the main research method, mathematical modeling was performed using the Aspen Plus V. 9 software package. As a model for describing the vapor–liquid equilibrium, the local composition equation-based UNIQUAC model was employed, and the Redlich–Kwong model was adopted to examine the non-ideal vapor phase. When modeling the conventional scheme of extractive distillation, parametric optimization was carried out according to the criterion of total energy costs in the reboilers of the columns. For economical evaluation, Aspen Process Economic Analyzer V10.1 tools were employed. Results. In comparison with the conventional extractive distillation scheme, three variants of schemes with vapor-recompression heat pumps were considered: with a heat pump placed on an extractive distillation column, on an extractive agent regeneration column, and with two heat pumps placed on both columns of the scheme. A scheme with an internal heat pump was also proposed, in which the heat pump compressor is located between sections of extractive columns that operate at different pressures: 506.6 kPa in the top sections and 101.3 in the bottom section. An economic analysis was conducted for all the considered schemes to calculate the total annual costs. It was shown that schemes with vapor-recompression heat pumps can significantly reduce the energy costs of extractive distillation by up to 39.6%; however, a significant reduction in the total annual costs is achieved only with sufficiently long operation periods of the plants. The reduction in the energy costs in the scheme with an internal heat pump was 44%, and the total annual costs were in the range of 20.2–30.1%, depending on the operating time of the plant. Conclusions. It was shown that using heat pumps in the extractive distillation of the mixture of isobutyl alcohol–isobutyl acetate with n-butyl propionate as the entrainer can significantly reduce energy costs. The scheme with an internal heat pump is the most economical of all the considered schemes.

EXTRACTION OF ANIONIC CADMIUM COMPLEXES WITH ORGANIC SOLUTIONS OF QUATERNARY AMMONIUM SALTS

The anion-exchange extraction of thiocyanate, chloride and iodide cadmium complexes by solutions of quaternary ammonium salts chlorides in organic solvents (toluene, carbon tetrachloride, ethyl acetate, isobutyl alcohol, nitrobenzene) was studied. Extraction involves solutions of alkyl dimethylbenzylammonium chlorides (R-N+(CH3)2-CH2C6H5-Cl-) and alkyl dimethylethyl-benzylammonium (R-N+(CH3)2-CH2-CH2C6H5-Cl-), where R is a straight alkyl chain, mainly C12 - C14. The composition of the cadmium anionic complexes was established by the analysis of the calibration curves E = f (pCCd (II)) constructed from cadmium sulfate solutions against the background of various contents of thiocyanate, chloride and iodide ions (ndicator electrode - ion-selective electrode with a membrane, which based on a nitrobenzene solution of tetradecylammonium bromide). The extraction process is estimated quantitatively using a distribution coefficient (D). The value of D is calculated taking into account the cadmium concentration in the aqueous phase before and after extraction. The dependence of the distribution coefficient on the organic solvent dielectric constant, the concentration and stability of the anionic complexes of cadmium is shown. So, for the indicated cadmium acidocomplexes, the minimum D values were obtained using low-polar toluene and carbon tetrachloride, and the maximum values were obtained using highly polar isobutyl alcohol and nitrobenzene. If the concentration of cadmium (II) is reduced by a factor of 100 for the cadmium rhodanide and iodide complexes, the value of D decreases by 1.6-1.9 times, for the chloride complex, by 1.2 times in the case of polar isobutyl alcohol and nitrobenzene, and 2.9-3.5 times in the case of low-polar solvents. It was experimentally established that in the series [Cd(SCN)4]2- - [CdI4]2-- [CdCl4]2- the value of D decreases for all the studied systems. The observed regularity is related both to the stability of the corresponding cadmium (II) complexes in aqueous solutions and to their hydrophobicity.