APPLICATION OF IMIDAZOLINES BASED ON TALL OIL FATTY ACIDS AND THEIR QUATERNARY SALTS FOR THE SEPARATION OF THE BINARY NON-AQUEOUS AZEOTROPE SYSTEMS

Методом экстрактивной (в том числе солевой) ректификации с использованием имидазолинов и четвертичных солей на их основе разделены на компоненты неводные двойные азеотропные системы. В качестве разделяющих агентов выбраны: промышленный продукт 1-гидроксиэтил-2-алкенил-2-имидазолин на основе жирных кислот таллового масла, а также его четвертичные соли - хлорид и тетрафторборат 1-гидроксиэтил-2-алкенил-3-бензил-2-имидазолиния. Для разделения были использованы неводные азеотропные системы: ацетон-метанол, метилацетат-метанол, этилацетат-этанол и хлороформ-метанол. Равновесие жидкость-пар в соответствующих тройных системах исследовано в модифицированном приборе Отмера при 101,3 кПа, состав жидкой и паровой фаз определен газохроматографическим методом анализа. Минимальные концентрации (в мольных долях) имидазолина и имидазолиниевых солей для разрушения азеотропов составили 0,156-0,264. Для корреляции экспериментальных данных о парожидкостном равновесии в системах, содержащих имидазолиниевые соли использована электролитная модель NRTL. Средние абсолютные отклонения расчетных данных от экспериментальных значений мольного содержания растворителей в паровой фазе и температуры в системах составили 0,007-0,008 и 0,25-0,35 К, соответственно. The non-aqueous binary azeotrope systems have been separated into components by the method of extractive rectification (and salt rectification) using imidazolines and their quaternary salts. The following were selected as separating agents: industrial product 1-hydroxyethyl-2-alkenyl-2-imidazoline based on tall oil fatty acids, as well as its quaternary salts - chloride and tetrafluoroborate 1-hydroxyethyl-2-alkenyl-3-benzyl-2-imidazolinium. Non-aqueous azeotrope acetone - methanol, methyl acetate - methanol, ethyl acetate - ethanol, and chloroform - methanol systems were used for separation. The vapor-liquid equilibrium in the corresponding ternary systems was investigated in a modified Othmer still at 101.3 kPa, the composition of the liquid and vapor phases was determined by gas chromatographic analysis. The minimum concentrations (in molar fractions) of imidazoline and imidazolinium salts for the azeotrope breaking were 0.156-0.264. The mean absolute deviations between experimental and calculated data for the solvent mole fraction in the vapor phase and temperature in the imidazolinium salt containing systems were 0,007-0,008 and 0,25-0,35 К respectively.

Assessment of the Carbon Footprint and VOCs Emissions Caused by the Manufacturing Process of the Footwear Industry in Bangladesh

Every industry has an impact on the environment, either good or bad, and leather and footwear industries are no exception. For the footwear industry, the main environmental impacts are the releasing of volatile organic compounds (VOCs) and solid wastes. The pressure of reducing harm to the environment is coming from both the consumers and the legislation. CO2 and VOCs are hazardous to human health and also trigger serious environment problems, such as ozone layer depletion, offensive odour, photochemical smog, acid rain and many others. Adhesives, finishing products and cleaners contribute to VOCs emissions in the footwear manufacturing industry. VOCs emission may also arise from primers, separating agents, printing inks or finishing pastes. Some most commonly produced VOCs in the footwear manufacturing industry are benzene, toluene, styrene, ethylene, xylene, acetaldehyde, formaldehyde, methyl ethyl ketone, chlorobenzene, phenol etc. All of these cause severe health problems in humans and have an adverse effect on the environment. An increasing number of footwear factories adversely affects the environment and human health. One of the largest environmental impacts of shoe industry comes from the manufacturing stages of the shoe’s life cycle. This study was carried out to measure the carbon footprint and VOCs emissions among ten selected footwear factories. The results revealed that the total energy footprint for one pair of shoes is 18.004826 MJ, the water footprint is 8.37167 litres and the carbon footprint is 9.174979 kg CO2 eq. The highest impact in terms of the carbon footprint lies in the shoe manufacturing process with a 5.85109 eq. CO2 (kg). The total VOCs consumption for a fashion shoe is around 36.5 g/pair on average. There should be an initiative taken with the aim of adjusting the choice of methods, materials, machines and the monitoring systems as well as the safety policy for the workers and the environment.

Comparative Study of Fluid Package on Extractive Distillation of Ethanol-water Mixture Using Pure Glycerol and Ethylene Glycol as Extracting Solvents

The comparative study of Peng Robinson Strygek Vera (PRSV) and Non-Random Two Liquid (NRTL) fluid packages on the extractive distillation of ethanol-water mixture was done using pure glycerol and ethylene glycol as extracting agents. The process was simulated using HYSYS V. 8.4. Pure glycerol and ethylene glycol-glycerol mixture were used as separating agents. The results showed the highest molar composition of ethanol in the distillate at the solvent feed rate of 80 kmol/hr when pure glycerol was used with NRTL fluid package. With the PRSV fluid package the highest ethanol in the distillate was obtained at pure glycerol feed rate of 50 kmol/hr. The ethanol fraction in the distillate was decreasing with increasing ethylene glycol and decreasing glycerol in the ethylene glycol-glycerol mixture. The comparative study of the base case and alternative designs showed high ethanol composition in distillate in the range of 99.46 - 99.96% and 99.96 - 99.67% for NRTL and PRSV fluid package, respectively. It was concluded from the study that the PRSV fluid package could save cost of operation because of lower solvent requirement and energy consumption in the reboiler for both the base case and alternative designs.

SELECTION OF EXTRACTIVE AGENTS FOR THE SEPARATION OF CHLOROFORM - METHANOL - TETRAHYDROFURAN MIXTURE

Variants of the extractive distillation of chloroform - methanol - tetrahydrofuran equimolar mixture with industrial separating agents are considered. The basic system shows opposite deviations from the ideal behavior, because it contains binary azeotropes with minimum and maximum boiling points (3.3.1-4 system according to Serafimov’s classification). The choice of selective substances for extractive distillation was carried out taking into account the concentration dependences of the excess molar Gibbs energy of the binary constituents of the derivative system “chloroform - methanol - tetrahydrofuran - industrial test agent (ethylene glycol (EG), dimethyl sulfoxide (DMSO), N-methylpyrrolidone (N-MP))” at 101.32 kPa. Based on the results of the evaluation of the thermodynamic criterion, DMSO and N-MP are recommended. Both agents show selective effect when separating two binary constituents. EG is selective only with respect to chloroform-tetrahydrofuran mixture. Since the tested agents show different selective effects, the final agent choice determines the qualitative composition of the product flows in the column for the extractive distillation of the three-component mixture (the first column of the flowsheet) and, accordingly, the structure of the total flowsheet. The schemes consist of two two-column complexes for extractive distillation (for the basic three-component mixture and for the binary mixture). The maximum contribution to the total reboiler energy consumption of the distillation columns is made by the first extractive distillation column: 65% (EG), 53% (N-MP) and 24% (DMSO). The use of the most selective agent reduces the energy consumption of this column: the reboiler load is maximal in the case of EG, in comparison with which the load is 47% lower in the case of N-MP and 76% lower in the case of DMSO.

Gas/vapour separation using ultra-microporous metal–organic frameworks: insights into the structure/separation relationship

In this tutorial review we discuss the latest developments in ultra-microporous MOF adsorbents and their use as separating agentsviathermodynamics and/or kinetics and molecular sieving.