scholarly journals Catalytic Stereoselective Conversion of Biomass-Derived 4′-Methoxypropiophenone to Trans-Anethole with a Bifunctional and Recyclable Hf-Based Polymeric Nanocatalyst

Polymers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2808
Author(s):  
Yixuan Liu ◽  
Dandan Chen ◽  
Mingrui Li ◽  
Heng Zhang ◽  
Hu Li

Anethole (AN) is widely used as an odor cleaner in daily necessities, and can also be applied in the fields of food additives, drug synthesis, natural preservatives, and polymeric materials’ preparation. Considering environmental and economic benefits, the use of biomass raw materials with non-precious metal catalysts to prepare high-value fine chemicals is a very promising route. Here, we developed an acid-base bifunctional polymeric material (PhP-Hf (1:1.5)) composed of hafnium and phenylphosphonate in a molar ratio of 1:1.5 for catalytic conversion of biomass-derived 4′-methoxypropiophenone (4-MOPP) to AN via cascade Meerwein–Pondorf–Verley (MPV) reduction and dehydration reactions in a single pot. Compared with the traditional catalytic systems that use high-pressure hydrogen as a hydrogen donor, alcohol can be used as a safer and more convenient hydrogen source and solvent. Among the tested alcohols, 2-pentanol was found to be the best candidate in terms of pronounced selectivity. A high AN yield of 98.1% at 99.8% 4-MOPP conversion (TOF: 8.5 h−1) could be achieved over PhP-Hf (1:1.5) at 220 °C for 2 h. Further exploration of the reaction mechanism revealed that the acid and base sites of PhP-Hf (1:1.5) catalyst synergistically promote the MPV reduction step, while the Brønsted acid species significantly contribute to the subsequent dehydration step. In addition, the PhP-Hf polymeric nanocatalyst can be recycled at least five times, showing great potential in the catalytic conversion of biomass.

2021 ◽  
pp. 78-81
Author(s):  
Ольга Викторовна Багрянцева ◽  
Сергей Анатольевич Хотимченко ◽  
Светлана Анатольевна Шевелева ◽  
Людмила Павловна Минаева ◽  
Полина Александровна Семенова

В последние годы в Российской Федерации (РФ) появились сообщения об использовании в пищевой промышленности технологического вспомогательного средства (ТВС) - ферментного препарата на основе микробиальной трансглютаминазы (мТГ), который не входит в перечень разрешенных для использования в пищевой промышленности Евразийского экономического союза (ЕАЭС). Анализ данных показал, что используемые в настоящее время в пищевой промышленности штаммы-продуценты мТГ - Streptomyces mobaraensis DSM40587 и Streptomyces mobaraensis S-8112 - наряду с этим ферментом могут синтезировать антибиотики блеомицин, детоксин, пиерицидин А, а также ферменты антибиотикоустойчивости, такие как пенициллин ацилазу, бета-лактамазу, что служит развитию антибиотикоустойчивости у микроорганизмов. При поступлении в желудочно-кишечный тракт (ЖКТ) в составе пищевой продукции мТГ может вызывать изменение структуры белков слизистой оболочки кишечника. Под влиянием мТГ увеличивается проницаемость стенки кишечника, происходит активация иммунного ответа, увеличивается антигенная нагрузка иммунной системы, происходит нарушение связи ДНК с гистонами. Показано, что мТГ может явиться причиной увеличения частоты проявления симптомов целиакии у гипосимптомных с неустановленным диагнозом генетически восприимчивых лиц, нарушения адгезии белков при формировании синдрома Альцгеймера, аллергии, а также нарушений иммунного статуса организма и микробиоценоза кишечника. Данный фермент является привлекательным для производителей в связи с высокой эффективностью применения мТГ в технологическом процессе производства пищевой продукции из некачественного и некондиционного сырья, что обуславливает значимые экономические выгоды и возможность отказа от использования пищевых добавок. Последнее позволяет формировать у потребителя представление о высоком качестве вырабатываемой пищевой продукции. В связи с установленными рисками здоровью населения при использовании мТГ, отсутствием разрешения на ее использование в пищевой промышленности ЕАЭС, возможностью применения этого фермента в целях введения в заблуждение потребителей считаем необходимым проведение дополнительных оценок рисков здоровью и введение обязательного мониторинга на наличие остаточной активности этого фермента в пищевой продукции. In recent years, in the Russian Federation (RF), there have been reports about use in the food industry of processing aid (PA) - an enzyme preparation based on microbial transglutaminase (mTG), which is not included in the list of permitted for use in the food industry of the Eurasian Economic Union (EAEU). Analysis of the data showed that the currently used in the food industry strains-producer of mTG - Streptomyces mobaraensis DSM40587 and Streptomyces mobaraensis S-8112, along with this enzyme, have been synthesizing antibiotics bleomycin, detoxin, piericidin A, as well as such enzymes - penicillin acylases, beta-lactamazes, which could be reasons of antibioticoresistance of microorganisms. mTG when introduced into the gastrointestinal tract as part of food, could change the structure of proteins in the intestinal mucosa. Under the influence of mTG have increased intestinal permeability, immune system antigenic load, have been promoted the immune response, have been intensifying connection between DNA and histones. It has been shown that mTG could cause an increase the frequency of detection of celiac disease in hyposymptomatic / with an undetermined diagnosis of genetically susceptible individuals, impaired protein adhesion during the formation of Alzheimer's syndrome, allergies, as well as impaired of immune status and gut's microbiosis. This enzyme is attractive to manufacturers due to the high efficiency of the use of mTG in the technological process of food production from low-quality and substandard raw materials, which leads to significant economic benefits and the possibility of abandoning the use of food additives. The latter fact allows the consumer to form an idea of the high quality of the produced food. In connection with the established risks mTG for public health, lack of permission for its use in the food industry of the EAEU and the possibility of using this enzyme in order to mislead consumers, we consider it necessary to carry out additional health risk assessments and introduce mandatory monitoring for the presence of residual activity of this enzyme in food.


Author(s):  
Ilya A. Babenko ◽  
Viktor A. Bezborodov ◽  
Alexey I. Vilms

This work presents the results of studying the behavior of catalytic systems formed on the basis of trichlorotris-(tetrahydrofuranate)chromium(III) in the presence of sulfur-containing tridentate SOS-type ligands and activated by various organoaluminum compounds. In the formation of catalytic systems, the following compounds were used: SOS-type ligands - bis-(2-methylthioethyl) ether, bis-(2-ethylthioethyl) ether and bis-(2-phenylthioethyl) ether, organoaluminum compounds - triethylaluminum, triisobutylaluminum, tributylaluminum and methylaluminoxane. In the course of test experiments aimed at choosing an activator at a temperature of 40 °C and an ethylene pressure of 2 MPa, the best results were obtained for triethylaluminum. Therefore, further experiments on the catalytic conversion of ethylene were carried out only with this activator. To study the effect of the reaction temperature and ethylene pressure in the reaction zone, catalytic systems of the trichlorotris-(tetrahydrofuranate)chromium(III)/ligand/triethylaluminum composition were studied in the temperature range from 40 to 80 °C and an ethylene pressure of 2 - 3 MPa with a molar ratio of components Cr : L : AlEt3 = 1 : 1 : 20. As a result of studies, it was shown that in all cases when using tridentate ligands of the SOS type, the catalytic systems formed by us showed a tendency not only to polymerization, but also to oligomerization of ethylene. The best results in the field of ethylene oligomerization into hexenes were shown by the system of the composition trichlorotris-(tetrahydrofuranate)chromium(III) / bis-(2-methylthioethyl) ether/triethylaluminum, in which the content of the hexene fraction is 54 - 55 wt.%, while the selectivity to hexene-1 reaches 88 - 89%.


2020 ◽  
Vol 63 (8) ◽  
pp. 1-10
Author(s):  
Nikita A. Panurin ◽  
◽  
Ekaterina B. Markova ◽  
Tatyana F. Sheshko ◽  
Alexander G. Cherednechenko ◽  
...  

This paper describes the synthesis of highly active and selective catalysts based on natural coal: Jerusalem artichoke, camelina, rape and wheat, and their modification with nanosized iron, for cracking associated petroleum gases (APG) using the example of propane, for solving the ecological problem of environmental pollution and the economic problem of raw materials for the production of a huge range of polymer materials used by mankind in almost all spheres of life. With the help of APG catalysis, an environmental problem can be solved. By sending APG for processing to obtain light olefins for the production of polymeric materials. Currently, catalysts using nanoparticles show high performance in selectivity, product yield, and so on. As the physical properties of nanoparticles affect their catalytic properties, and how catalyst fabrication parameters can in turn affect these physical properties, nanocatalysts can be designed that are highly active, highly selective, and reasonably stable. Also activated carbons from natural plant raw materials have very good adsorption properties, but the nature and kinetics of adsorption are determined not only by the type of natural raw materials, but also by the temperature and other parameters of the technological characteristics of the carbon materials obtained. Also, the use of catalysts in this area is environmentally beneficial, since it allows you to reduce the temperatures of the cracking processes and increase the yield of products of interest. The elemental composition of catalytic systems has been established. The acidity of catalytic systems of both natural coals modified with iron and simple natural coals has been established. A high catalytic activity of modified catalytic systems was revealed – the conversion of associated petroleum gas reaches a maximum at 900 K. A high selectivity in the formation of olefins, about 95% at the maximum conversion, for the obtained catalysts was established.


2020 ◽  
Vol 10 (1) ◽  
pp. 16-19
Author(s):  
Tasnia Ahmed ◽  
Md Aftab Uddin

Spreads are used widely for making the fast foods more amazing and tasty. Varieties and cross combinations of ingredients are used to make many flavours of fast foods. Different restaurants prepare their signature spreads for attracting people but this can cause opposite result if not prepared using high quality raw materials and proper hygienic conditions are not maintained. Current study was conducted on ten different types of spreads (pesto, cilantro, queso, tomato sauce, peanut butter, honey, mustard, cream cheese, chocolate sauce and butter) which are used by the local restaurants in Dhaka city, Bangladesh. Almost all the samples (nine out of ten) harbored total viable bacteria exceeding the standard limit. Four spread samples showed high fungal count (102 cfu/gm). Four samples showed to be positive (˃101/ml recommended acceptable count) for Escherichia coli and Klebsiella spp. which indicates that these spread cannot be recommended for public consumption. Among all the samples examined, only chocolate sauce showed acceptable result without the presence of coliforms, Staphylococcus spp. and Pseudomonas spp. This finding suggests proper maintenance of sanitation in spread preparation and selling area. A proper guidelines and monitoring can help keep up the quality of food additives. Stamford Journal of Microbiology, Vol.10 (1) 2020: 16-19


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Youjing Li ◽  
Fen Li ◽  
Ying Yang ◽  
Baocai Ge ◽  
Fanzhu Meng

Abstract In view of the serious environmental pollution, which is the greatest problem the world is facing, and the continuous consumption of raw materials, it is imminent to search for green and sustainable resources. Lignin is an organic polymer that exists widely in nature, and if it can be transformed from traditional low-value waste product with low range of applications to functional materials with high application prospects, it can be of great significance to alleviate environmental pollution and shortage of fossil resources. One of the functional applications of lignin involves its use to fabricate composite with other polymeric materials, which can then be used to prepare membrane materials. This review summarizes the recent research and application progress of combining lignin with polypropylene, polyvinyl alcohol, starch, cellulose, chitosan, and other polymeric materials to prepare composite membranes; and summarizes the future development direction of lignin-based composite membranes. We hope this review may provide a new perspective to the understanding of lignin-based composite membranes and a useful reference for future research.


Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1865
Author(s):  
Rida Tajau ◽  
Rosiah Rohani ◽  
Mohd Sofian Alias ◽  
Nurul Huda Mudri ◽  
Khairul Azhar Abdul Halim ◽  
...  

In countries that are rich with oil palm, the use of palm oil to produce bio-based acrylates and polyol can be the most eminent raw materials used for developing new and advanced natural polymeric materials involving radiation technique, like coating resins, nanoparticles, scaffold, nanocomposites, and lithography for different branches of the industry. The presence of hydrocarbon chains, carbon double bonds, and ester bonds in palm oil allows it to open up the possibility of fine-tuning its unique structures in the development of novel materials. Cross-linking, reversible addition-fragmentation chain transfer (RAFT), polymerization, grafting, and degradation are among the radiation mechanisms triggered by gamma, electron beam, ultraviolet, or laser irradiation sources. These radiation techniques are widely used in the development of polymeric materials because they are considered as the most versatile, inexpensive, easy, and effective methods. Therefore, this review summarized and emphasized on several recent studies that have reported on emerging radiation processing technologies for the production of radiation curable palm oil-based polymeric materials with a promising future in certain industries and biomedical applications. This review also discusses the rich potential of biopolymeric materials for advanced technology applications.


Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3497
Author(s):  
Piotr Stachak ◽  
Izabela Łukaszewska ◽  
Edyta Hebda ◽  
Krzysztof Pielichowski

Polyurethanes (PUs) are a significant group of polymeric materials that, due to their outstanding mechanical, chemical, and physical properties, are used in a wide range of applications. Conventionally, PUs are obtained in polyaddition reactions between diisocyanates and polyols. Due to the toxicity of isocyanate raw materials and their synthesis method utilizing phosgene, new cleaner synthetic routes for polyurethanes without using isocyanates have attracted increasing attention in recent years. Among different attempts to replace the conventional process, polyaddition of cyclic carbonates (CCs) and polyfunctional amines seems to be the most promising way to obtain non-isocyanate polyurethanes (NIPUs) or, more precisely, polyhydroxyurethanes (PHUs), while primary and secondary –OH groups are being formed alongside urethane linkages. Such an approach eliminates hazardous chemical compounds from the synthesis and leads to the fabrication of polymeric materials with unique and tunable properties. The main advantages include better chemical, mechanical, and thermal resistance, and the process itself is invulnerable to moisture, which is an essential technological feature. NIPUs can be modified via copolymerization or used as matrices to fabricate polymer composites with different additives, similar to their conventional counterparts. Hence, non-isocyanate polyurethanes are a new class of environmentally friendly polymeric materials. Many papers on the matter above have been published, including both original research and extensive reviews. However, they do not provide collected information on NIPU composites fabrication and processing. Hence, this review describes the latest progress in non-isocyanate polyurethane synthesis, modification, and finally processing. While focusing primarily on the carbonate/amine route, methods of obtaining NIPU are described, and their properties are presented. Ways of incorporating various compounds into NIPU matrices are characterized by the role of PHU materials in copolymeric materials or as an additive. Finally, diverse processing methods of non-isocyanate polyurethanes are presented, including electrospinning or 3D printing.


2014 ◽  
Vol 906 ◽  
pp. 66-71
Author(s):  
Zhen Quan Li ◽  
Qiang Zhen ◽  
Ya Li Wang

High purity ZrSiO4 powder were synthesized using Si (C2H5O)4 and ZrOCl2·8H2O as raw materials by the sol-gel method, LiCl was added as mineralizer to promote crystallization of zircon. The influences of molar ratio of Zr:Si, calcined time and calcined temperature on the synthesis of ZrSiO4 powder were investigated. XRD, SEM and TEM were used to characterize the powders. It was found that when the molar ratio of Zr:Si was 1:1.2, the calcined temperature was 1600°C and the calcined time was 4h, the high purity ZrSiO4 ultrafine powder was obtained. The ZrSiO4 formation began at 1300°C and when the gel was calcined at 1600°Cfor 4 h, the formation rate of ZrSiO4 was up to 95%. SEM and TEM studies reveal a homogeneous product with particle sizes on the order of 0.1-1μm. The IR emissivity of ultrafine ZrSiO4 is 0.892 at the whole wavelength range, and that is up to 0.951 at the wavelength range of 8-14 μm.


2012 ◽  
Vol 67 (10) ◽  
pp. 961-975 ◽  
Author(s):  
Markus Hölscher ◽  
Christoph Gürtler ◽  
Wilhelm Keim ◽  
Thomas E. Müller ◽  
Martina Peters ◽  
...  

With the growing perception of industrialized societies that fossil raw materials are limited resources, academic chemical research and chemical industry have started to introduce novel catalytic technologies which aim at the development of economically competitive processes relying much more strongly on the use of alternative carbon feedstocks. Great interest is given world-wide to carbon dioxide (CO2) as it is part of the global carbon cycle, nontoxic, easily available in sufficient quantities anywhere in the industrialized world, and can be managed technically with ease, and at low cost. In principle carbon dioxide can be used to generate a large variety of synthetic products ranging from bulk chemicals like methanol and formic acid, through polymeric materials, to fine chemicals like aromatic acids useful in the pharmaceutical industry. Owing to the high thermodynamic stability of CO2, the energy constraints of chemical reactions have to be carefully analyzed to select promising processes. Furthermore, the high kinetic barriers for incorporation of CO2 into C-H or C-C bond forming reactions require that any novel transformation of CO2 must inevitably be associated with a novel catalytic technology. This short review comprises a selection of the most recent academic and industrial research developments mainly with regard to innovations in CO2 chemistry in the field of homogeneous catalysis and processes.


2021 ◽  
Vol 9 (16) ◽  
pp. 98-108
Author(s):  
Yuliia Kozonova ◽  
◽  
Liubov Teleghenko ◽  
Vita Atanasova ◽  

Deficiency of most micronutrients, imbalance in nutrition, together with a dangerous environmental situation in Ukraine, has led to a decrease in the immunity of the population and the spread of alimentary-dependent diseases. Due to the damaged immunological picture of the population in recent years, the relevance of the creation of immunomodulating products is significantly increasing. About 70% of dishes served in restaurant are released with sauces, which allows not only to improve the aroma, appearance and taste of the finished dish, but also to increase the content of the essential substances of the dish. In the assortment of sauce products on the Ukrainian market, most of the sauces contain preservatives, artificial stabilizers and emulsifiers that negatively affect the human body and are not recommended for daily consumption. The subject of research is sauce products for preventive nutrition with increased nutritional value, without the presence of artificial food additives in the composition. The purpose of the study is to develop formulations of immunomodulating sauces using natural raw materials. Methods. The object of the study - developed immunomodulating sauces. In the finished product, the following parameters were determined: titratable acidity (DSTU 4957:2008), microbiological indicators (GOST 10444.15-94, GOST 54728-92, GOST 10444.2-94, GOST 30519-97). The results of the study. As a result of a literature search, the substances were determined, their bigger content in dies being important for improvement in the state of the immune system. These substances include, first of all, antioxidant vitamins (C, A and E), polyunsaturated fatty acids (especially omega-3), mineral elements and other minor substances. During developing the formulations of immunomodulating sauces, twelve requirements were formulated.. As a result of the raw materials selection, three formulations of immunomodulating sauces have been proposed. In their technology, there is a high-temperature heat treatment, which allows maximizing the preservation of useful thermolabile components. Scope of research results. Ready-made sauces are sold in restaurant establishments and consumed locally. Due to their simplicity of preparation, they can also be recommended for making at home. The developed immunomodulating sauces have a pleasant appearance and harmonious taste, which is confirming the data of sugar-acid indices.


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