Andrey Nikolaevich Evdokimov

Сульфатный лигнин, являясь крупнотоннажным побочным продуктом в производстве целлюлозы, в основном применяется в содорегенерационном котле в процессе получения сульфида натрия, и лишь его небольшая часть, из-за его сложной структуры, используется в химически модифицированном виде. Тем не менее сульфатный лигнин обладает потенциалом для синтеза востребованных продуктов с большой добавленной стоимостью. В отличие от сульфатного лигнина лигносульфонаты, благодаря своим индивидуальным физико-химическим свойствам, пользуются стабильным спросом за счет применения в различных отраслях промышленности. Однако производство сульфитной целлюлозы, по сравнению с сульфатной, несоизмеримо меньше, и, как следствие, общее количество товарных лигносульфонатов не удовлетворяет потребности рынка. Таким образом, наблюдается неоднозначная ситуация – недоиспользование потенциала сульфатного лигнина в синтезе продуктов, обладающих аналогичными свойствами лигносульфонатов, на фоне увеличения потребности в лигносульфонатах. В работе показана возможность модификации сульфатного лигнина. Метод функционализации структуры хвойного сульфатного лигнина, включающий окисление перекисью водорода или гипохлоритом натрия гидроксильных групп и их метилирование диметилсульфатом с последующим присоединением гидросульфита натрия к образовавшимся карбонильным группам, позволил получить продукт, растворимый в кислой и нейтральной средах. Полученный растворимый лигнин по своим физико-химическим параметрам практически идентичен промышленным жидким лигносульфонатам, что делает его перспективным для использования в аналогичных технологических процессах. Sulfate lignin is a large-tonnage by-product in the pulp production. It’s mainly used in black liquor recovery boiler in the production of sodium sulfide, and only a small part of it, due to its complex structure, is used in a chemically modified form. Nevertheless, sulfate lignin has the potential to synthesize sought after products with high added value. Unlike sulfate lignin, lignosulfonates, due to their individual physics-chemical properties, are in stable demand due to their use in various industries. However, the production of sulfite cellulose is disproportionately lower than that of sulfate cellulose, and as a result, the total number of commercial lignosulphons does not meet the needs of the market. Thus, there is an ambiguous situation – the underutilization of the potential of sulfate lignin in the synthesis of products with similar properties of lignosulfonates, against the background of an increased demand for lignosulfonates. The study shows the possibility of modifying sulfate lignin. The method of functionalization of the coniferous sulfate lignin structure, including the oxidation of hydroxyl groups with hydrogen peroxide or sodium hypochlorite, and their methylation with dimethyl sulfate, followed by the addition of sodium hydrosulfite to the formed carbonyl groups, made it possible to obtain a product soluble in acidic and neutral media. The obtained soluble lignin is almost identical in its physics-chemical properties to industrial liquid lignosulfonates, which makes it promising for use in similar technological processes.

Salts with large organic ions, including those related to ionic liquids, are effective separating agents (entrainer) for azeotropic mixtures. The creation of processes for separating azeotropic mixtures by the action of salts – the processes of extractive, and in this case, salt rectification is based, among other things, on data on phase equilibria in such systems. The article is devoted to the study of the isobaric vapor-liquid equilibrium in the methyl acetate–methanol–1-butyl-1-methylpyrrolidinium trifluoromethanesulfonate system at 101.3 kPa and organic salt concentrations (in mole fraction) of 0.08, 0.10 and 0.25. The azeotropic mixture methyl acetate–methanol is a by-product of some organic synthesis processes. For the separation of this system by salt rectification, it is proposed to use the ionic liquid 1-butyl-1-methylpyrrolidinium trifluoromethanesulfonate. The effect of trifluoromethanesulfonate on the vapor-liquid equilibrium and the breaking of the azeotropic mixture was studied in a modified Othmer still using the head space gas chromatographic method. Thus, it was established for the first time that the use of 1-butyl-1-methylpyrrolidinium trifluoromethanesulfonate as a separating agent promotes the destruction of the methyl acetate–methanol azeotropic mixture. The concentration of methyl acetate in the vapor phase increases with the concentration of pyrrolidinium salt in the methyl acetate-methanol mixture. Thus, 1-butyl-1-methylpyrrolidinium trifluoromethanesulfonate has a salting-out effect. Pyrrolidinium salt with trifluoromethanesulfonate anion has been demonstrated lower efficiency as a separating agent compared to ionic liquid with the same cation and dicyanamide anion. The electrolyte Non Random Two Liquid model was used to describe the vapor-liquid equilibrium. This model demonstrated high accuracy in calculating the concentration of mixed solvent components in the vapor phase. The average absolute deviation between the calculated and experimental data on the concentration of mixed solvent components in the vapor phase was 0.006. To separate the mixed solvent into components, a calculated concentration by NRTL model of 1-butyl-1-methylpyrrolidinium trifluoromethanesulfonate of 0.186 mole fraction is required. For citation: Evdokimov A.N., Kurzin A.V., Tarazanov A.A. Vapor-liquid equilibrium in the system methyl acetate – methanol – 1-butyl-1-methylpyrrolidinium trifluoromethanesulfonate. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2026. V. 69. N 3. P. 16-22. DOI: 10.6060/ivkkt.20266903.7295.

In order to obtain high-quality pentaerythritol rosin esters (with a color on the Gardner scale of no more than 3 and a softening point of no less than 101 °C), which are mainly used as adhesives in road marking compositions, the possibility of using disproportionated tall oil rosin as a source of resin acids with Gardner scale color no more than 2. The application of disproportionated rosin as a raw material made it possible to carry out the esterification in the temperature range of 260–270 °C which traditionally used in the synthesis of rosin esters without catalysts, technological additives, protective inert atmosphere and vacuum distillation. As a result, pentaerythritol rosin esters with high quality characteristics were obtained: color on the Gardner scale no more than 3, acid number no more than 10 mg KOH∙g-1, softening point no less than 103 °C. Similar esters of disproportionated tall oil rosin can also be obtained from other alcohols (methanol, ethanol, ethylene glycol and glycerol) and used as the basis for adhesive compositions and additives for various purposes, in which their color and its stability are important.

С целью расширения областей применения диспропорционированной талловой канифоли с низким значением цветности по шкале Гарднера и для получения проклеивающих составов (катионных клеев) для бумаги и картона синтезированы полиамидоаминовые и полиамидоамин-эпихлоргидриновые смолы. Получение полиамидоаминовой смолы на основе диспропорционированной талловой канифоли, адипиновой кислоты, диэтилентриамина и 2-аминоэтанола осуществляли в вакууме, при температуре 140–150 °С в течение 7 ч, а присоединение эпихлоргидрина к полиамидоамину и получение полиамидоами-нэпихлоргидриновой смолы – при 40–60 °С в течение 1 ч. Установлено, что 20%-ные растворы полиамидоаминовой и полиамидоамин-эпихлоргидриновой смол стабильны при хранении в течение 30 суток при температуре 20–24 °С, динамическая вязкость при 25°С составила 105 и 114 мПа∙с соответственно. Цвет 50%-ных растворов ухудшился незначительно по сравнению с исходной диспропорционированной талловой канифолью – не более 3 по шкале Гарднера. In order to expand the areas of application of disproportionated tall oil rosin with a low color value on the Gardner scale and to obtain the sizing compositions (cationic sizes) for paper and cardboard, the polyamidoamine and polyamidoamineepichlorohydrin resins have been synthesized. The synthesis of polyamidoamine resin based on disproportionated tall oil rosin, adipic acid, diethylenetriamine, and 2- aminoethanol was carried out in vacuum at 140–150 °C for 7 hours, the addition of epichlorohydrin to polyamidoamine and the preparation of polyamidoamineepichlorohydrin resin – at 40–60°C for 1 hour. It was found that 20% solutions of polyamidoamine and polyamidoamine-epichlorohydrin resins are stable when stored for 30 days at 20–24 °C, the dynamic viscosity at 25 °C was 105 and 114 mPa·s, respectively. The color of 50% solutions deteriorated slightly compared to the original disproportionated tall oil rosin not more 3 on the Gardner scale.

The liquid–vapor equilibrium in the toluene–methanol–N-octylquinolinium bromide system has been studied at 101.3 kPa and various concentrations of the organic salt. It was shown that the quinolinium salt can be used as a separating agent for a toluene–methanol azeotrope mixture. For breaking the azeotrope and separating the mixed solvent into components, the N-octylquinolinium bromide concentration (in mole fractions) should be 0.55 or higher.

The liquid–vapor equilibrium in the toluene–methanol–N-octylquinolinium bromide system has been studied at 101.3 kPa and various concentrations of the organic salt. It was shown that the quinolinium salt can be used as a separating agent for a toluene–methanol azeotrope mixture. For breaking the azeotrope and separating the mixed solvent into components, the N-octylquinolinium bromide concentration (in mole fractions) should be 0.55 or higher.

The possibility of obtaining polysaccharide esters based on large-scale products of plant origin: inulin and tall oil fatty acids, was studied. Carbohydrate esters of the biopolymer inulin and higher unsaturated acids were synthesized by acylation with acid chlorides under various conditions: in a water–chloroform mixture in the presence of sodium hydroxide and sodium salts of tall oil fatty acids, as well as in a pyridine–1,4-dioxane mixture. The yield of polysaccharide esters was 67–82%, the maximum yield was detected during the acylation of inulin in the pyridine–1,4-dioxane system.

A study is performed of using quinolinium salt as a separating agent for double azeotropic mixtures in the process of extractive distillation. Gas chromatography is employed to study the liquid–vapor equilibrium in a methanol–benzene–chloride N-benzylquinolinium system at 101.3 kPa and different concentrations of organic salt. It is established that a 0.25 concentration (in mole fractions) of chloride N-benzylquinolinium or more is needed to destroy the azeotrope and separate the mixed solvent into components.

The possibility of using Na₂В₄O₇ and Na₂В₄O₇∙10H₂O as catalysts for transesterification of triacyl glycerides (with sunflower oil as example) with methanol to obtain biodiesel fuel was examined. At the molar ratio of sunflower oil to methanol of 1 : 12, temperature of 65°С, reaction time of 2 h, and catalyst concentration of up to 5 wt %, the maximal yield of the methyl esters of the fatty acids was 65 and 95% with Na₂В₄O₇∙10H₂O and Na₂В₄O₇, respectively. Na₂В₄O₇ can be used as a triglyceride transesterification catalyst no less than three times without appreciable change in the yield of fatty acid methyl esters. Na₂В₄O₇ can be recommended as a catalyst for transesterification involving other esters and alcohols.

С целью расширения области применения жирных кислот таллового масла – побочного продукта сульфатной варки целлюлозы (которые преимущественно состоят из непредельных С18-кислот), в том числе за счет получения различных синтетических продуктов на их основе, синтезированы соответствующие этиленгликолевый и додециловый эфиры. Изучена возможность применения указанных сложных эфиров в качестве депрессорных присадок для марок универсального топливного мазута и судового экологического топлива. Жирные кислоты этерифицированы 1-додеканолом и этиленгликолем в присутствии катализатора п-толуолсульфокислоты. Температуру текучести топлив определяли ручным методом по стандарту ASTM D97. Температура текучести топлива судового экологического снизилась с +21 до 0 °С при использовании 2% додецилового эфира жирных кислот в качестве присадки. Установлено, что синтезированные эфиры жирных кислот таллового масла снижают температуру текучести остаточных топлив на уровне, сравнимом с применением промышленно производимой депрессорной присадки, что позволяет расширить сырьевую базу присадок этого типа и сократить закупки по импорту, а также более глубоко использовать жирные кислоты таллового масла в органическом синтезе. In order to expand the field of application of tall oil fatty acids, a by-product of sulfate pulping (which mainly consist of unsaturated C18 acids), including the production of various synthetic products based on them, the corresponding ethylene glycol and dodecyl esters have been synthesized. The possibility of application the esters as pour point depressants for grades of universal fuel oil and marine ecological fuel has been studied. Fatty acids were esterified with 1-dodecanol and ethylene glycol in the presence of a p-toluenesulfonic acid as catalyst. The pour point of the fuels was determined manually according to the ASTM D97 standard. The pour point of ecological marine fuel decreased from +21 to 0 °C when using 2% dodecyl ester of fatty acids as an additive. It was found that the synthesized esters of tall oil fatty acids reduce the pour point of residual fuels at a level comparable to the use of a commercially produced depressant additive, which makes it possible to expand the feedstock base of this type of additives and reduce import purchases, as well as to use more extensively tall oil fatty acids in organic synthesis.