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1

Szkielety metalo-organiczne do zastosowań w zakresie ochrony środowiska

Baluk Mateusz Adam, Trzebiatowska Patrycja Jutrzenka, Pieczyńska Aleksandra

Wiadomości Chemiczne

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2024

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[Z] 78, 3-4

189--217

EN

Current challenges related to climate change, environmental degradation, and the increasing energy demand impose an urgent need for society to seek innovative solutions in environmental protection. In response to these issues, scientists have been developing areas related to novel functional nanomaterials for years. Among these materials, particular attention is drawn to metal-organic frameworks (MOFs), a new type of porous coordination polymers built from metal centers and organic ligands. The exceptional properties of MOFs come from their porous structure exhibiting high surface area, low density, large pore volume, also recyclability and the ability to regulate pore size and activity by selecting appropriate building blocks. MOFs can be synthesized by various routes and the most popular methods are the following: solvo-(hydro)thermal, mechanochemical, electrochemical, sonochemical or microwave-assisted synthesis. The type of synthesis influences the MOFs properties such as crystal size, specific surface area or possibility of scalable. Furthermore, MOFs activity in sorption or catalysis can be enhanced by postsynthetic modification (PSM), which enables the introduction of new functional groups or particles on/into MOF. Thanks to these properties and tunability, MOFs are finding increasingly broad applications in various processes that can serve different functions such as catalysts, photocatalysts, or sorbents. Due to the possibility of control of pore structure, their adsorption properties, and the nature of active sites, lately, MOFs and MOF-based materials have been investigated in gas adsorption and separation, hydrogen storage, CO2 capture, chemical sensing, electrochemical water splitting, biomass conversion, polymerization and drug delivery. This article will provide general information about the structure and key properties of MOFs, as well as methods of their synthesis and possibilities for modification. However, the focus will primarily be on indicating the various applications of MOFs in environmental applications (Figure 1). The use of MOFs in processes for removing organic and inorganic pollutants from water, air purification, gas separation, pollutant detection, and fuel generation and storage will be discussed. Additionally, the potential uses of MOFs as catalysts in transesterification processes, CO2 fixation, depolymerization, or biomass conversion will be highlighted.

2

Removal of Organic Pollutants from Wastewater Using Different Oxidation Strategies

Fajri Nibras Raad, Mohammed Rusul Naseer

Journal of Ecological Engineering

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2023

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Vol. 24, nr 10

351--359

EN

Many countries use nontraditional methods to treat wastewater, especially those with water lacks. Among these methods, heterogeneous photocatalysis is more commonly widely used since it converts organic molecules into carbon dioxide and water. In this study, the photocatalytic degradation process of total organic carbon was investigated by TIO2/UV technique (TUT). This treatment is carried out in a batch recycle reactor using a UV light and catalyst TIO2. The optimum operating parameters were investigated regarding the best organic removal including, total organic carbon concentration, flow rate, pH, irradiation time, and photocatalysis dosage. The result showed that the TUT is affected by reducing total organic carbon (TOC) from synthetic wastewater (SW) by 61% at 50 ml/min of flow rate, 250 mg of catalyst concentration TIO2, and a concentration of TOC of 25 mg/l. Then the result of TUT was compared with a process of combining TIO2/UV and an oxidizing agent (Hydrogen peroxide H2O2). It was found that 73% of organic removal was obtained which is best than TUT when using an H2O2 dosage of 100 mg/l. Experimentally, Ozone was also added to the process of TUT and the result showed that the removal percentage increased to 80%.

3

Alkoholiza mocznika jako potencjalna metoda otrzymywania węglanu propylenu na skalę techniczną

Kotyrba Łukasz, Siewniak Agnieszka, Woszczyński Piotr, Nowakowska-Bogdana Ewa, Chrobok Anna

Przemysł Chemiczny

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2022

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T. 101, nr 12

1112--1117.

PL

Przeprowadzono test katalizatorów w procesie syntezy węglanu propylenu metodą alkoholizy mocznika. Spośród katalizatorów cynkowych, cynowych, glinokrzemianowych i MgO największe wydajności reakcji uzyskano, stosując zasadowy węglan cynku (78,9%) i tlenek cynku (76,9%). Badania wykazały, że tlenek cynku nie traci swoich właściwości katalitycznych po kolejnych nawrotach, jednak jego straty po każdym cyklu reakcyjnym wynosiły 27,4 - 33,1%. Dowiedziono, że rozpuszczony w mieszaninie poreakcyjnej cynk może być z niej usunięty za pomocą wymieniaczy jonowych, takich jak ziemia bieląca TONSIL 570 FF lub kationit Purolite CT151.

EN

Propylene glycol, urea and catalyst (compds. of Zn, Mg, Sn or aluminosilicates) were mixed in the flow of N₂, at 150°C, for 4 h. The compn. of the reaction mixt. was detd. by means of GC with an internal standard. The Zn content of the liq. samples was quantified by X-ray fluorescence. The highest yields of propylene carbonate were obtained in the presence of basic ZnCO₃ (78.9%) and ZnO (76.9%). ZnO losses after each reaction cycle amounted to 27.4-33.1%. The Zn dissolved in the reaction mixt. was removed with the aid of ion exchangers.

4

Synteza i zastosowanie styrylopochodnych arenów, karbazolu i ferrocenu w projektowaniu e-stereoregularnych krzemoorganicznych materiałów hybrydowych

Majchrzak Mariusz

Wiadomości Chemiczne

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2021

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[Z] 75, 1-2

137--162

EN

The potential for expanding the variety of catalytic methods for carbon-carbon bond formation is being currently explored in many research centres all over the world. An increasing use of selected d-block metals as catalysts in the synthesis has brought new methods of functionalization of organic and organometallic compounds of great importance for development of polymer chemistry and organic chemical technology [5, 6]. This work describes very precise and controlled catalytic transformations as useful tools for the synthesis of new E-conjugated organic, organosilicon molecular and polymeric compounds. The combination of Suzuki-Miyaura coupling and silylative coupling reactions as a simple and efficient method is established for designing new E-stereoregular hybrid materials in the presence of well-defined transition metal (TM) catalysts. All presented compounds can be interesting precursors for a further functionalization that may significantly increase the possibility of their application in the design and synthesis of new functional materials.

5

CO2 zamiast CO : katalityczna konwersja CO2 w syntezie związków karbonylowych

Wójcik Ewelina, Trzeciak Anna M.

Wiadomości Chemiczne

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2021

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[Z] 75, 3-4

395--422

EN

Modem industrial carbonylation processes, leading to functionalized carbonyl compounds, are based on the application of highly toxic and flammable carbon monoxide. Recently, carbon dioxide which is non-toxic and abundant, has attracted attention as a perfect C1 source to build new C-C and C-N bonds. From the standpoint of green and sustainable chemistry, it is appealing and challenging to combine the reduction of CO2 with subsequent carbonylation using in situ formed CO. Herein we present the application of CO2 as C1 building block for the carbonylation of different organic compounds in the presence of transition metal catalysts (e.g. Pd, Rh, Ru, Fe). Industrially important organic compounds has been obtained in hydroformylation, dehydrogenation, hydrogenation, aminocarbonylation and carboxylation reactions with CO2. On the other hand, rapid reduction of CO2 to CO could processed in the metal catalyst - free systems, using a catalytic amount of fluoride salt and stoichiometric amount of di- or hydrosilane. In these reactions silyl formate has been identified as an important intermediate formed from silane and carbon dioxide. Also hydrazine and sodium borohydrate have been used for CO2 reduction to formic acid or other products. Obviously, these reactions could be restricted because of their sensitivity to the applied conditions, high cost of reactants as well as the waste generated. The presented examples of catalytic carbonylation reactions with CO2 as a source of CO group illustrate a high technological potential of this strategy.

6

Experimental Insight into the Catalytic Mechanism of MFe2O4 (M = Ni, Zn and Co) on the Thermal Decomposition of TKX-50

Hou Xiaoting, Zhang Ming, Zhao Fengqi, Yang Yanjing, An Ting, Li Hui, Pan Qing, Wang Xiaohong, Zhang Kun

Central European Journal of Energetic Materials

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2021

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Vol. 18, no. 2

223--244

EN

Synthesized dihydroxylammonium 5,5’-bistetrazole-1,1’-diolate (TKX-50) owes its outstanding application prospects in the field of insensitive solid propellants not only to its high energetic performance but also to its low mechanical sensitivity. Based on the excellent catalytic activity of bimetallic iron oxides for the thermal decomposition of TKX-50, the catalytic mechanism of bimetallic iron oxides (NiFe2O4, ZnFe2O4 and CoFe2O4) for TKX-50 pyrolysis has been explored. For this study, the decomposition process of TKX-50, before and after mixing with the bimetallic iron oxides NiFe2O4, ZnFe2O4 and CoFe2O4 was monitored by in-situ FTIR and gas-phase MS-FTIR instruments. Of the different catalysts, ZnFe2O4 gave the best result for reducing the initial decomposition temperature of TKX-50. Additionally, the activation energy of functional group cleavage of TKX-50, before and after mixing with ZnFe2O4, was also calculated for mechanism analysis from the results of the in-situ FTIR measurements. The results showed that the condensate and the gas-phase decomposition products of TKX-50 remained unchanged after mixing with different catalysts, while the activation energy of tetrazole ring cleavage was significantly reduced. The results of this study will be helpful for the rational design of insensitive solid propellant formulations containing TKX-50, and for understanding the pyrolysis mechanisms of TKX-50 before and after mixing with the efficient catalyst ZnFe2O4.

7

Characteristics of the structure of natural zeolites and their potential application in catalysis and adsorption processes

Sobuś Natalia, Czekaj Izabela, Diichuk Volodymyr, Kobasa Igor M.

Technical Transactions

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2020

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Vol. 117, iss. 1

art. no. e2020043

EN

Authors present a short review of selected natural-origin zeolite materials. This article discusses the structure, classification and ability to modify natural zeolites, along with examples of their potential applications as adsorbents or catalysts.

PL

Autorzy przedstawili krótki przegląd wybranych materiałów zeolitowych pochodzenia naturalnego. W artykule omówiono strukturę, klasyfikację i możliwości modyfikacji naturalnych zeolitów, wraz z przykładami ich potencjalnych zastosowań jako adsorbentów lub katalizatorów.

8

Charakterystyka struktury elektronowej heteropolikwasu fosforowolframowego H3PW12O40 modyfikowanego kationem Fe2+

Niemiec Piotr Jan

Science, Technology and Innovation

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2020

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Vol. 11, no. 4

24--32

PL

W pracy zbadano wpływ podstawienia atomu wolframu atomem żelaza w pierwszorzędowej strukturze heteropolikwasu fosforowolframowego o budowie anionu Keggina. Charakterystykę struktury elektronową zmodyfikowanego heteropolikwasu przeprowadzono za pomocą: analizy populacyjnej NBO, całkowitych (PDOS) i parcjalnych (PDOS) widm gęstości stanów, energetyki i charakteru chemicznego orbitali granicznych (HOMO/LUMO) oraz rozmiaru przerwy wzbronionej (gap). Dodatkowo zbadano mechanizm oddziaływania modyfikowanego kationem Fe2+ heteropolikwasu fosforowolframowego z cząsteczką H2O pełniącą rolę środowiska reakcji chemicznej. W większości charakterystyk stwierdzono istotny wpływ wprowadzonego metalu przejściowego na ww. właściwości w stosunku do heteropolikwasu wyjściowego H3PW12O40.

EN

In this paper the influence of substituting the tungsten atom with an iron ion in the primary structure of the phosphotungstic heteropolyacid with the Keggin anion structure was investigated. Characterization of the electronic structure of the modified heteropolyacid was performed using: population analysis according to NBO scheme, total (TDOS) and partial (PDOS) density of states spectra, energy and chemical character of frontier orbitals (HOMO/LUMO) and the size of the HOMO-LUMO band gap. Additionally, the mechanism of interaction between the Fe2+ with H2O molecule, acting as a chemical reaction medium, was investigated. Most cases showed a significant effect of the introduced transition metal ion (Fe2+) on the above-mentioned properties in relation to the nonmodified heteropolyacid H3PW12O40.

9

Katalizatory palladowe immobilizowane w materiałach typu MOF aktywne w reakcjach uwodornienia

Augustyniak Adam W., Trzeciak Anna M.

Wiadomości Chemiczne

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2019

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[Z] 73, 3-4

221--241

EN

Palladium immobilized in metal-organic frameworks (MOF) exhibit promising catalytic properties in hydrogenation of different unsaturated substrates. Due to the specific porous and crystalline structure MOFs can contribute in bonding and activation of organic substrates, increasing catalytic efficiency of Pd@MOF composites. The superior tunability of MOFs structures enables to design highly selective catalysts for hydrogenation of different substrates, such as olefins, esters, ketones, alcohols or alkynes. Due to the synergistic effects of palladium and MOF not only high activity but also high selectivity can be achieved. The article presents representative examples of MOF-based palladium catalysts for hydrogenation to illustrate perspectives, also technological, of their application.

10

A study of ruthenium-based catalysts used in homogeneous transfer hydrogenation of acetophenone

Mikołajczyk Filip, Kamiński Kamil

Chemical and Process Engineering

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2019

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Vol. 40, nr 2

213–-222

EN

A detailed comparison of catalytic properties of two different ruthenium-based catalysts in the reaction of homogeneous hydrogenation of acetophenone was performed. Additionally, methods of synthesis of both catalysts were tested and optimized in order to achieve the best possible quality and purity of the final catalysts. NMR analysis was used to analyze and identify the composition of ruthenium compounds and gas chromatography was used to analyze the conversion rate of hydrogenation reactions. It was determined that RuCl2(PPh3)3 obtained with a modified method described by Shaw’s group (Shawet al., 2007) had the best catalytic properties in the reaction performed under conditions described in Liang Wang’s publication (Wang et al., 2014). It was also determined that for concentration ratio of substrate to RuCl2(PPh3)3 amounting to 250:1 the conversion rate was much higher than that of the reaction performed with a double dose of the catalyst. Results of experiments also show that samples of the post-reaction solution should be analyzed right after the reaction, because even if they are stored in low temperature the amount of product can change up to 3–5% compared to the base sample and this change is not predictable. These findings have significant implications for further research of the reaction of homogeneous transfer hydrogenation of ketones. With the right catalysts and methods of their synthesis other parameters of this reaction can be optimized. The most important one is a change of solvent from isopropyl alcohol to a less toxic substance like water. This may increase the value of the reaction in green chemistry and chemical industry.

11

Modelling of regeneration and filtration mechanism in diesel particulate filter for development of composite regeneration emission control system

Kurien C., Srivastava A. K., Naudin J.

Archive of Mechanical Engineering

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2018

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Vol. LXV, nr 2

277--290

EN

Pre-treatment techniques employed for exhaust emission control of compression ignition engines were found to reduce the emission levels by small percentage only, failing to meet the required emission regulations. Post-treatment technique including diesel particulate ﬁltration, diesel oxidation catalysis and selective catalytic reduction is found to be an eﬀective solution. While the fuel-based regeneration of diesel particulate ﬁlter leads to uncontrolled combustion aﬀecting the durability of the ﬁlter. Development of an eﬀective regeneration system is one of the major technical challenges faced by automotive industry for meeting emission norms. A composite regeneration system with the application of microwave energy is proposed in this paper. As an initial phase, a three-dimensional model of the system is developed and its ﬂow analysisis carried out by considering the case of single channel ﬂow. Simulation of the regeneration process is also done by developing a Simulink model. The results of simulation showed that an engine running continuously for a period of 24 hours would require three regenerations.

12

Decomposition of hydrogen perodixe - kinetics and review of chosen catalysts

Pędziwiatr P., Mikołajczyk F., Zawadzki D., Mikołajczyk K., Bedka A.

Acta Innovations

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2018

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no. 26

45--52

EN

Hydrogen peroxide is a chemical used in oxidation reactions, treatment of various inorganic and organic pollutants, bleaching processes in pulp, paper and textile industries and for various disinfection applications. It is a monopropellant, which, when purified, is self-decomposing at high temperatures or when a catalyst is present. Decomposing to yield only oxygen and water(disproportionation), hydrogen peroxide is one of the cleanest, most versatile chemicals available. The catalytic decomposition of hydrogen peroxide allows the use of various catalysts that will increase the rate of decomposition. Comparison and description of the most commonly used catalysts were presented in this review.

13

Biomasa - źródło cennych związków organicznych

Retajczyk J., Wróblewska A.

Wiadomości Chemiczne

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2017

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[Z] 71, 3-4

241--262

EN

So far, much attention was paid to processes which allow to obtain biofuels from biomass and less important was receiving from biomass valuable chemical compounds. Biomass is a source of a variety of compounds, such as: hydrocarbons, triglycerides, glycerol, hydroksymetylofurfural, cellulose, hemicellulose and pentoses, lignin and lignocellulose. Taking into account the application of the mentioned above compounds, a large number of articles describing catalytic conversion of biomass to valuable chemical compounds has been written during last 10 years. The articles presented specific types of reactions for compounds contained in biomass, such as: hydrolysis, hydrogenation or isomerization, which allow to obtain valuable products. The reactions are catalyzed among others by: metals deposited on the activated carbon, metal oxides, alloys and zeolites. Researchers still improve processes, adapting them to the structure of highly functionalized particles contained in biomass and process needs. At the same time, scientist focused on cost reduction. Renewable raw materials are converted to the intermediates in physical, chemical and physicochemical processes. Next, obtained intermediates are used for receiving valuable chemicals, such as: lubricants, solvents and products that were previously obtained from petroleum. This work presents the conversion of biomass to compounds which have been already prepared by conventional synthetic methods. Besides chemical pure compounds, catalytic reactions with using metals, lead to obtain mixtures of compounds which can be used for the large volume production: additives for paper, paints, resins, foams, surfactants, lubricants and plasticizers. In the chemical industry for many years it has been placed emphasis on processes that are environmentally friendly. Scientists have also focused on improving the activity of used catalysts and the selectivity of products.

14

Możliwości katalitycznego zastosowania materiałów odpadowych

Książek S., Kida M., Koszelnik P.

Czasopismo Inżynierii Lądowej, Środowiska i Architektury / Journal of Civil Engineering, Environment and Architecture

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2017

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z. 64, nr 2/II

55--62

PL

Zrównoważona chemia stanowi jedną z form działań zmierzających do zmniejszenia zanieczyszczeń środowiska i jest ważnym elementem zrównoważonego rozwoju. Zielona chemia dostarcza rozwiązań do takich globalnych wyzwań jak zmiana klimatu, zrównoważone rolnictwo, energia, zatrucie środowiska i wyczerpywanie bogactw naturalnych. Zielone technologie nie tylko chronią środowisko naturalne, ale zazwyczaj są również korzystne z punktu widzenia ekonomicznego. Podstawowym problemem dla środowiska jest znaczne zmniejszenie się zapasu surowców naturalnych. Zatem, dążenie do większej rozmaitości źródeł surowcowych to ważny obszar działania zielonej chemii. Kataliza należy do podstawowych narzędzi realizowania wszystkich zasad zielonej, zrównoważonej chemii wychodząc od badań podstawowych do zastosowań przemysłowych. Według zasad zielonej chemii, gdzie tylko jest to możliwe, powinno dążyć się do stosowania surowców odnawialnych oraz odpadów, które nie tylko zapewniają alternatywne surowce odnawialne, ale także stanowią materiał do produkcji katalizatorów. Zastosowanie materiału naturalnego jako katalizatora lub substratu do wytwarzania katalizatora powoduje nie tylko obniżenie kosztów związanych z produkcją katalizatorów, ale sprawia, że stosowany proces jest przyjazny dla środowiska. Ponadto, wykorzystanie materiałów odpadowych zmniejsza problem unieszkodliwiania odpadów. Wśród najbardziej obfitych zasobów produktów ubocznych technologii są przede wszystkim odpady z rolnictwa, górnictwa i produkcji metali, a w szczególności przemysłu hutniczego. Celem pracy jest scharakteryzowanie właściwości katalitycznych wybranych materiałów odpadowych.

EN

Sustainable chemistry is one of the forms of action to reduce pollution of the environment and it is an important element of sustainable development. Green chemistry provides solutions to such global challenges as climate change, sustainable agriculture, energy, toxics in the environment and the depletion of natural resources. Green technology will not only protect the environment, but they are usually also preferable from the economic point of view. The main concern for the environment is a significant reduction in the supply of natural materials. Therefore, the pursuit of a greater variety of sources of natural materials is an important area of activity of green chemistry. Catalysis is one of the basic tools of implementation of all principles of green, sustainable chemistry, from basic research to industrial applications. According to the seventh principle of green chemistry, where possible, should seek to use renewable raw materials and waste, which not only provide alternative renewable raw materials, but also provide the material for the production of catalysts. The use of natural material or waste material as catalyst or a substrate for the preparation of the catalyst will not only reduce the costs associated with the production of catalysts, but makes the used process is environmentally friendly. Waste materials also are valuable materials for the production of catalysts or are themselves active catalysts. In addition, the use of waste materials reduces the problem of waste disposal. Among the most abundant resources of technology products are primarily agricultural, mining and metals, and in particular the steel industry. The aim of the work is to characterize the catalytic properties of selected waste materials.

15

Charakterystyka powierzchni materiałów nanostrukturalnych z użyciem powierzchniowo wzmocnionej spektroskopii ramana

Chlebda D. K.

Technical Issues

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2016

|

nr 1

8--13

EN

Nowadays, surface-enhanced Raman spectroscopy (SERS) is being considered as a rapid and powerful vibrational spectroscopy technique for chemical analysis of materials. The Very high incensement in the intensities of the Raman signal allows for application of that method for chemical analysis of nanostructured surfaces covered with suitable enhancing substrates. For SERS measurements, the substrate plays an essential role because it provides a localized metal surface plasmon resonance enhancement of analyte molecules. Moreover, the use of SERS has a great potential to overcome the Raman spectroscopy weaknesses connected with intensity problems and, therefore, can be applied to the field of heterogeneous catalysts. This article reviews the application of nanoparticles substrates as a ground for SERS enhancement. The article also focuses on the recent progress in SERS characterization of catalytic materials. Recent developments in the field of catalytic material characterization for selected tested molecules allow for performing valuable and reproducible SERS experiments on working catalysts in the reaction environment.

16

Zastosowanie związków renu w katalizie

Malarz J., Leszczyńska-Sejda K., Benke G., Ciszewski M.

Rudy i Metale Nieżelazne Recykling

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2016

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R. 61, nr 10

429--434

PL

W artykule przedstawiono przykłady katalizatorów renowych stosowanych w reakcjach epoksydacji, metatezy olefin oraz innych reakcjach pozwalających na utworzenie nowych wiązań węgiel-węgiel, węgiel-heteroatom (C-N, C-O, C-S), a także w reakcjach utleniania czy redukcji. Stosowane w tych reakcjach związki renu to nie tylko proste katalizatory organiczne (np. MTO), ale również złożone związki kompleksowe zawierające rozbudowane ligandy, a także heterogeniczne katalizatory osadzone na stałych nośnikach. Najbardziej znanym katalizatorem renowym jest MTO (metylotrioksoren(VII), CH3ReO3), który wykazuje aktywność w reakcjach metatezy olefin i epoksydacji, ale również w reakcjach utleniania alkoholi oraz eterów. Z punktu widzenia katalizy heterogenicznej, ważnym katalizatorem jest tlenek renu(VII) osadzony na stałym nośniku (np. Al2O3, SiO2 czy Al2O3-SiO2). Tego typu katalizatory stosowane są przede wszystkim w reakcjach metatezy olefin. Ponadto bimetaliczne katalizatory renowo- platynowe osadzone na stałych nośnikach, są stosowane w procesie reformingu surowej benzyny.

EN

Rhenium catalysts are widely applied in various chemical reactions in an industrial scale. Owing to produced catalysts complex organic compounds, which synthesis is impossible or impeded by other methods, maybe obtained. This work exemplifies application of rhenium catalysts in epoxidation and metathesis reactions of olefins as well as other react/on types al¬lowing formation of new carbon-carbon and carbon-heteroatom (C-N, C-0, C-S! bonds and also in oxidation and reduction reactions. Rhenium compounds used in these reactions are not only simple organic catalysts such as MTO but complex compounds containing well-developed //-gands and heterogeneous catalysts embedded on solid matrices too. MTO (methyltrioxorheniumlVlll CH3ReO}) is probably the most known rhenium catalyst that is active in olefins metathesis and epoxidation reactions and in alcohols and ethers oxidation reactions too. Based on heterogeneous catalysis rhenium(VII) oxide deposited on a solid matrix e.g. Alfl^ 5i02 or Alfl3-5i02 is an important catalyst's type that is mainly used in metathesis reactions. In addition bimetallic rhenium-platinum catalysts deposited on solid matrices are used in raw gasoline reforming.

17

Combining laccase with Cu(salen) catalysts for oxidation of kraft lignin

Zhou X. F., Tang K.

Drewno : prace naukowe, doniesienia, komunikaty

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2016

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vol. 59, nr 198

35--47

EN

The transformation of kraft lignin using laccase with Cu(salen) catalysts was studied. The effect of the laccase/MCM – to – laccase/MCM + Cu(salen)/NaY ratio on the yields of monomeric aromatic chemicals (MACs) and the molecular weight (Mw) of kraft lignin was studied. The MACs yield decreased as the ratio increased, and the vanillin yield reached its highest value when the ratio of laccase was 50 wt % at a reaction temperature of 80 °C. The formation of MACs was enhanced by using a combination of laccase with Cu(salen) catalysts, while the formation of vanillin was dominant in the process. The formation of 4-hydroxy-3,5-dimethoxy benzaldehyde, 2-methoxy phenol, 4-hydroxy-3,5- -dimethoxyphenyl ethanone, 4-hydroxy-3-methoxyphenyl ethanone, 4-hydroxy- -3,5-dimethoxy benzoic acid, 4-hydroxy benzaldehyde, and 2-methoxy-4- -vinylphenol was also found in this work. The effect of the reaction parameters on the MACs yield and the Mw of the kraft lignin was described, and the main reactions occurring in the kraft lignin were discussed.

18

Mezoporowate materiały węglowe jako obiecujące katalizatory utleniającego odwodornienia alkanów

Jarczewski S., Kuśtrowski P.

Chemik

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2016

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Vol. 70, nr 6

298--309

PL

Atrakcyjne właściwości, do których zaliczyć można rozwiniętą powierzchnię właściwą, uporządkowany układ szerokich kanałów wewnątrz ziarnowych oraz obecność względnie dużej liczby powierzchniowych grup tlenowych, sprawiają, że mezoporowate materiały węglowe cieszą się ogromnym zainteresowaniem licznych grup badawczych związanych z chemią materiałów oraz katalizą. W pracy przedstawiono krótki przegląd dotyczący możliwości użycia materiałów węglowych o kontrolowanej mezostrukturze jako katalizatorów reakcji utleniającego odwodornienia alkanów.

EN

Peculiar properties, such as a high specific surface area, an ordered arrangement of wide intraparticle pores as well as a relatively high concentration of surface oxygen-containing functional groups, make mesoporous carbons interesting materials for various research groups working in the field of materials chemistry and catalysis. In this work, a short review concerning the possibility of application of carbon materials with controlled mesostructure as catalysts for the oxidative dehydrogenation of alkanes is presented.

19

Synthesis, characterization and fabrication of copper nanoparticles in N-isopropylacrylamide based co-polymer microgels for degradation of p-nitrophenol

Farooqi Z. H., Sakhawat T., Khan S. R., Kanwal F., Usman M., Begum R.

Materials Science Poland

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2015

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Vol. 33, No. 1

185--192

EN

Poly(N-isopropylacrylamide-co-acrylic acid) [P(NIPAM-co-AAc)] microgels were synthesized by precipitation polymerization. Copper nanoparticles were successfully fabricated inside the microgels by in-situ reduction of copper ions in an aqueous medium. The microgels were characterized by Fourier Transform Infrared Spectroscopy (FT-IR) and Dynamic Light Scattering (DLS). Hydrodynamic radius of P(NIPAM-co-AAc) microgel particles increased with an increase in pH in aqueous medium at 25 °C. Copper-poly(N-isopropylacrylamide-co-acrylic acid) [Cu-P(NIPAM-co-AAc)] hybrid microgels were used as a catalyst for the reduction of 4-nitrophenol (4-NP). Effect of temperature, concentration of sodium borohydride (NaBH4) and catalyst dosage on the value of apparent rate constant (kapp) for catalytic reduction of 4-NP in the presence of Cu-P(NIPAM-co-AAc) hybrid microgels were investigated by UV-Vis spectrophotometry. It was found that the value of kapp for catalytic reduction of 4-NP in the presence of Cu-P(NIPAM-co-AAc) hybrid microgel catalyst increased with an increase in catalyst dosage, temperature and concentration of NaBH4 in aqueous medium. The results were discussed in terms of diffusion of reactants towards catalyst surface and swelling-deswelling of hybrid microgels.

20

Poly(N-isopropylacrylamide-co-methacrylic acid) microgel stabilized copper nanoparticles for catalytic reduction of nitrobenzene

Farooqi Z. H., Butt Z., Begum R., Khan S. R., Sharif A., Ahmed E.

Materials Science Poland

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2015

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Vol. 33, No. 3

627--634

EN

Pakistan Poly(N-isopropylacrylamide-co-methacrylic acid) microgels [p(NIPAM-co-MAAc)] were synthesized by precipitation polymerization of N-isopropylacrylamide and methacrylic acid in aqueous medium. These microgels were characterized by dynamic light scattering and Fourier transform infrared spectroscopy. These microgels were used as micro-reactors for in situ synthesis of copper nanoparticles using sodium borohydride (NaBH4) as reducing agent. The hybrid microgels were used as catalysts for the reduction of nitrobenzene in aqueous media. The reaction was performed with different concentrations of catalyst and reducing agent. A linear relationship was found between apparent rate constant (kapp) and amount of catalyst. When the amount of catalyst was increased from 0.13 to 0.76 mg/mL then kapp was increased from 0.03 to 0.14 min−1. Activation parameters were also determined by performing reaction at two different temperatures. The catalytic process has been discussed in terms of energy of activation, enthalpy of activation and entropy of activation. The synthesized particles were found to be stable even after 14 weeks and showed catalytic activity for the reduction of nitrobenzene.