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Dewaxing by isomerization is widely used to produce winter and arctic grades of diesel fuel. Preliminary feed hydrotreatment and pure hydrogen are usually used in order to avoid poisoning of the catalyst by sulfur and nitrogen. However, combining hydrotreatment and dewaxing in one reactor has some advantages, such as lower capital and operating costs. In such a configuration, a dewaxing catalyst works in sour environments, defined by sulfur and nitrogen presented in the feed stream. In the presented work, Pt-containing catalysts based on commercial zeolites with one-dimensional channels and their mixtures (ZSM-23, ZSM-22, ZSM-12, EU-2, SAPO-11, ZSM-23+ZSM-12, and ZSM-23+EU-2) were prepared, characterized using different analytical techniques (X-ray diffraction, scanning electron microscopy, transmission electron microscopy, inductively coupled plasma atomic emission spectroscopy, N2 sorption, and infrared spectroscopy), and tested in dewaxing of the diesel fraction under sour conditions. It was found that catalyst activity, dewaxed product yield, and quality indicators (aromatic hydrocarbon content and density) were highly sensitive to zeolite channel size, while catalyst acidity and zeolite crystal size were less important factors. The highest activity was shown by catalysts based on EU-2 and ZSM-12, which had the widest channels. The highest product yield was observed for the catalyst based on EU-2, which had a medium channel size among compared zeolites. Wider zeolite channels promoted the metal function of catalysts that led to a decrease in the aromatic hydrocarbon content of dewaxed products. Using the mixtures of ZSM-23+ZSM-12 and ZSM-23+EU-2 did not lead to visible synergetic effects. Using different binder materials (Al2O3, TiO2, and ZrO2) did not significantly affect the quality or yield of dewaxed products.

Introduction. The present research featured the effect of carbonyls, phenols, furans, fatty alcohols, ethers, and other chemical compounds on the sensory properties of cognac distillates of different ages. The research objective was to identify additional criteria of sensory evaluation by measuring the effect of various compounds on perception intensity. Study objects and methods. The study featured cognac samples of different ages. The experiment involved standard methods, including high-performance liquid and gas chromatography and a mathematical analysis based on Microsoft software. Results and discussion. The content of fatty alcohols, ethers, and carbonyl compounds that formed as a result of fermentation demonstrated little change during the aging period in oak casks. A longer extraction increased the content of phenolic and furan compounds and sugars. The content of terpene compounds decreased due to their high lability. The study revealed the effect of organic compounds on taste descriptors. The article introduces multivariate equations that calculate the dependences of the descriptor intensity on the content of organic compounds. A correlation and regression analysis revealed that phenolic compounds had a significant effect on the taste formation of cognac samples, depending on the aging time. Conclusion. Organic compounds proved to affect the taste profiles of cognac samples of different ages, as well as sensory evaluation descriptors.

Recent studies have revealed an interest in the composition of beer biomolecules as a colloidal system and their influence on the formation of beer taste. The purpose of this research was to establish biochemical interactions between the biomolecules of plant-based raw materials of beer in order to understand the overall structure of beer as a complex system of bound biomolecules. Generally accepted methods of analytical research in the field of brewing, biochemistry and proteomics were used to solve the research objectives. The studies allowed us to establish the relationship between the grain and plant-based raw materials used, as well as the processing technologies and biomolecular profiles of beer. The qualitative profile of the distribution of protein compounds as a framework for the formation of a colloidal system and the role of carbohydrate dextrins and phenol compounds are given. This article provides information about the presence of biogenic compounds in the structure of beer that positively affect the functioning of the body. A critical assessment of the influence of some parameters on the completeness of beer taste by biomolecules is given. Conclusion: the conducted analytical studies allowed us to confirm the hypothesis about the nitrogen structure of beer and the relationship of other biomolecules with protein substances, and to identify the main factors affecting the distribution of biomolecules by fractions.