Zeolithe - Maßgeschneiderte "Reaktionsgefäße" mit Nanodimensionen

This contribution presents a short overview of the state-ofthe-art and prospects of zeolitic molecular sieves as versatile microporous materials for science and technology. Zeolites are crystalline framework aluminosilicates. The regular pore system of the zeolites, with cavities and channels of subnanometre dimensions, as well as the characteristic properties resulting therefrom, predestine them for a broad range of applications as ion exchangers, adsorbents and catalysts in chemical technology. The most recent results of zeolite research prove that the potential of zeolitic molecular sieves is still far from being exhausted, and that various subsections of chemistry, physics, biology, microstructure technology, etc. are directing increasing interest to this substance class.Der Beitrag gibt einen kurzen Überblick zum Stand und zu Perspektiven zeolithischer Molekularsiebe als vielseitige mikroporöse Materialien für Wissenschaft und Technik. Zeolithe sind kristalline Gerüst- Alumosilicate. Das regelmäßige Porensystem der Zeolithe mit Hohlräumen und Kanälen in Subnanometerdimensionen sowie die daraus resultierenden charakteristischen Eigenschaften prädestinieren sie für einen breiten Einsatz als Ionenaustauscher, Adsorbentien und Katalysatoren in der chemischen Technik. Die neueren Erkenntnisse der Zeolithforschung belegen, dass das Anwendungspotenzial zeolithischer Molekularsiebe noch lange nicht erschöpft ist und dass vielfältige Teilgebiete der Chemie, Physik, Biologie, Mikrostrukturtechnik etc. dieser Substanzklasse zunehmendes Interesse entgegenbringen

Bioethanol im Fokus der nachhaltigen Energie- und Chemiewirtschaft

Gegenwärtig stellen die fossilen Ressourcen Erdöl, Erdgas und Kohle die wichtigste Rohstoffbasis für die Energie- und Chemiewirtschaft dar. Doch ist ein Wechsel zu erneuerbaren Rohstoffen in greifbare Nähe gerückt. Hierbei muss insbesondere die pflanzliche Biomasse und das daraus erhältliche Bioethanol als nahezu unerschöpfliche Rohstoffquelle betrachtet werden. Neben der energetischen Nutzung von Bioethanol kann es darüber hinaus als Plattformchemikalie zum Aufbau neuer Chemikalienstammbäume verwendet werden.The fossil resources oil, natural gas and coal are currently the most important fuels and raw materials for the energy and chemicals industries. A switch to renewable resources, however, is now within grasp. In this context, crop-based biomass and the bioethanol which can be obtained therefrom can be seen as practically inexhaustible sources of raw materials. Alongside the use of bioethanol as a fuel, it could also serve as a platform chemical for new derivative product families

Conversion of the Propane–Butane Fraction into Arenes on MFI Zeolites Modified by Zinc Oxide and Activated by Low-Temperature Plasma

The effect of modification of MFI zeolite 1–5 wt.% ZnO activated by plasma on acid and catalytic properties in the conversion of the propane–butane fraction into arenes was investigated. The high-silica zeolites with silicate module 45 were synthesized from alkaline alumina–silica gels in the presence of an ‘X-oil’ organic structure-forming additive. The modification of the zeolite with zinc was carried out by impregnating the zeolite granules in the H-form with an aqueous solution of Zn(NO3)2. The obtained zeolites were characterized by X-ray phase analysis and IR spectroscopy. It is shown that the synthesized zeolites belong to the high-silica MFI zeolites. The study of microporous zeolite-containing catalysts during the conversion of C3-C4 alkanes to aromatic hydrocarbons made it possible to establish that the highest yield of aromatic hydrocarbons is observed on zeolite catalysts modified with 1 and 3% ZnO and amount to 63.7 and 64.4% at 600 °C, respectively, which is 7.7–8.4% more than on the original zeolite. The preliminary activation of microporous zeolites modified with 1–5% ZnO and plasma leads to an increase in the yield of aromatic hydrocarbons from the propane–butane fraction; the maximum yield of arenes is observed in zeolite catalysts modified with 1 and 3% ZnO and activated by plasma, amounting to 64.9 and 65.5% at 600 °C, respectively, which is 8.9–9.5% more than on the initial zeolite. The activity of the zeolite catalysts modified by ZnO and activated by plasma show good agreement with their acid properties. Activation of the zeolites modified by 1 and 3% ZnO and plasma leads to an increase in the concentration of the weak acid sites of the catalyst to 707 and 764 mmol/g in comparison with plasma-inactivated 1 and 3% ZnO/ZKE-XM catalysts at 626 and 572 mmol/g, respectively

Conversion of the Propane–Butane Fraction into Arenes on MFI Zeolites Modified by Zinc Oxide and Activated by Low-Temperature Plasma

The effect of modification of MFI zeolite 1–5 wt.% ZnO activated by plasma on acid and catalytic properties in the conversion of the propane–butane fraction into arenes was investigated. The high-silica zeolites with silicate module 45 were synthesized from alkaline alumina–silica gels in the presence of an ‘X-oil’ organic structure-forming additive. The modification of the zeolite with zinc was carried out by impregnating the zeolite granules in the H-form with an aqueous solution of Zn(NO3)2. The obtained zeolites were characterized by X-ray phase analysis and IR spectroscopy. It is shown that the synthesized zeolites belong to the high-silica MFI zeolites. The study of microporous zeolite-containing catalysts during the conversion of C3-C4 alkanes to aromatic hydrocarbons made it possible to establish that the highest yield of aromatic hydrocarbons is observed on zeolite catalysts modified with 1 and 3% ZnO and amount to 63.7 and 64.4% at 600 °C, respectively, which is 7.7–8.4% more than on the original zeolite. The preliminary activation of microporous zeolites modified with 1–5% ZnO and plasma leads to an increase in the yield of aromatic hydrocarbons from the propane–butane fraction; the maximum yield of arenes is observed in zeolite catalysts modified with 1 and 3% ZnO and activated by plasma, amounting to 64.9 and 65.5% at 600 °C, respectively, which is 8.9–9.5% more than on the initial zeolite. The activity of the zeolite catalysts modified by ZnO and activated by plasma show good agreement with their acid properties. Activation of the zeolites modified by 1 and 3% ZnO and plasma leads to an increase in the concentration of the weak acid sites of the catalyst to 707 and 764 mmol/g in comparison with plasma-inactivated 1 and 3% ZnO/ZKE-XM catalysts at 626 and 572 mmol/g, respectively

Application of the Global Optimization Method for the Parameters Identification of the Mathematical Model for the Transesterification Reaction of Vegetable Oil in the Microreactor

В даний час актуальним є застосування мікрореакційних технологій для виробництва біопалив шляхом переетерифікації рослинних олій етиловим спиртом. Ця реакція описується складною математичною моделлю. Для ідентифікації параметрів математичної моделі необхідно провести глобальну оптимізацію.Nowadays the use of microreactor technologies for production of biofuels by the transesterification of vegetable oils with ethanol is very relevant. This reaction is described by complex mathematical model. To identify the parameters of a mathematical model, it is necessary to carry out a global optimization.В настоящее время актуальным является применение микрореакционных технологий для получения биотоплив путем переэтерификации растительных масел этиловым спиртом. Эта реакция описывается сложной математической моделью. Для идентификации параметров математической модели необходимо произвести глобальную оптимизацию

"Комп'ютерне моделювання і керування в техніці та технологіях КМКТТ-2021", Дев’ята міжнародна науково-практична конференція

Економічні та екологічні показники каталізатора (активність, селективність, стабільність) є ключем до ефективного проведення каталітичних процесів. Для досягнення оптимальної продуктивності каталізатора необхідно володіти знаннями не тільки про природу його функціональності, а й розуміти, в якому місці і в який спосіб їх треба об'єднати в одне ціле, щоб отримати більш активні і селективні каталітичні центри. На окремих прикладах (ізомеризація, каталітичний крекінг, асиметричне гідрування, конверсія етанолу) буде представлена концепція мультифункціональності каталізатора як ефективного шляху підвищення інтенсифікації процесів.The economic and environmental performance of a catalyst (activity, selectivity, stability) is the key element determining the effectivity of a catalytic process. To achieve optimal catalyst performance, it is necessary to understand not only the nature of its functionalities, but also to knew where and how they should be combined into a single whole in order to obtain more active and selective catalytic sites. Taking selected examples (isomerization, catalytic cracking, asymmetric hydrogenation, ethanol conversion), the concept of catalyst multifunctionality as an effective way to increase the intensification of processes will be discussed.Экономические и экологические показатели катализатора (активность, селективность, стабильность) являются ключом к эффективному проведению каталитических процессов. Для достижения оптимальной производительности катализатора необходимо владеть знаниями не только о природе его функциональности, но и понимать, в каком месте и каким образом их надо объединить в одно целое, чтобы получить более активные и селективные каталитические центры. На отдельных примерах (изомеризация, каталитический крекинг, асимметрическое гидрирование, конверсия этанола) будет представлена концепция многофункциональности катализатора как эффективного пути повышения интенсификации процессов

Моделювання сумісної газової адсорбції на природньому та модифікованому цеолітах

Adsorption is of great importance. The unique advantage of adsorption over other separation methods is the higher selectivity that can be achieved by adsorbents. In addition, adsorption phenomena play a vital role in many solid-state reactions and biological mechanisms. In this work, the adsorption process of CO2 on the clinoptilolite (Skorynskoho field, Transcarpathian region, Ukraine) and SO2, NO, and CO2 adsorption on K2CO3-modified – γ -alumina in a fixed-bed reactor were theoretical studied and simulated by computer-mathematic methods. The developed mathematical model based on the mass balance in gas and solid phase, the experimental saturation capacities, considering the activity of the adsorbent with respect to the gas by variable coefficients. The model presented by a normal linear system of differential equations with variable coefficients, it was solved by Taylor collocation method. The simulation shows that the data obtained by theoretical study are in agreement with data obtained in the simulation. According to Fisher Criterion the mathematic model adequate in 90 % for modified zeolite and in 75 % for natural zeolite, it can be explained by unordered structure of the natural zeolite. It follows that the offered model adequately describes the dynamics simultaneous adsorption of gases over zeolites. Thus even with a large number of simplifications and assumptions, it is possible to construct efficient mathematical model that can be used in exhaust system. The results indicate that, there is great sense to conduct further researches and simulations to reach the industrial level.Работа посвящена теоретическому изучению и моделированию процесса адсорбции СО2 на клиноптилолите (Скоринское месторождение, Закарпатская область, Украина) и процесса адсорбции SO2, NO, и CO2 на K2CO3-модифицированном - γ-оксид алюминия. Математическая модель динамики совместной газовой адсорбции построена на основе материального баланса в газовой и твердой фазе с учетом активность адсорбента по отношению к газу по переменными коэффициентами. Робота присвячена теоретичному вивченню та моделюванню процесу адсорбції СО2 на кліноптилоліті (Скоринське родовище, Закарпатська область, Україна) та процесу адсорбції SO2, NO, і CO2 на K2CO3-модифікованому - γ-оксид алюмінію. Математична модель динаміки сумісної газової адсорбції побудована на основі матеріального балансу в газовій та твердій фазі з урахуванням активність адсорбенту по відношенню до газу по змінними коефіцієнтами.

Catalysis on Zeolites and Zeolite-like Materials

When the Swedish mineralogist Axel F [...

Studies on the Binary MgO/SiO2 Mixed Oxide Catalysts for the Conversion of Ethanol to 1,3-Butadiene

The demand for 1,3-butadiene, one of the most important raw materials in the rubber industry, is constantly increasing. The Lebedev process is a classical method of producing 1,3-butadiene from ethanol, which is to be optimized with regard to the mixed oxide catalysts used. In this work, the binary MgO/SiO2 solid system was tested with regard to its optimum chemical composition for the catalytic conversion of ethanol to 1,3-butadiene. Furthermore, novel mesoporous mixed oxides were prepared to investigate their textural, structural, and surface chemical properties as well as the catalytic activity. Nitrogen physisorption, scanning electron microscopy (SEM), and temperature-programmed ammonia desorption (NH3-TPD) measurements were carried out and evaluated. It was shown that the optimum yield of 1,3-butadiene is achieved by using MgO/SiO2 mixed oxide catalysts with 85–95 mol% MgO and not, as suggested by Lebedev, with 75 mol% MgO. The NH3-TPD measurements revealed that the maximum acid-site density is achieved with an equimolar up to magnesium-rich composition. During the synthesis of binary MgO/SiO2 solid systems based on mesoporous MgO, a thermally stable and ordered structure was formed in the autoclave, depending on the carbonate used and on the duration of the treatment