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Efficient and Clean Catalytic Hydrogenolysis of Aromatic Ketones by Silica Supported Schiff Base Modify Chitosan-Palladium Catalyst  [PDF]
Tingting Gu, Lijun Liu, Changqiu Zhao
Modern Research in Catalysis (MRC) , 2013, DOI: 10.4236/mrc.2013.21002
Abstract: An silica supported chitosan-Schiff base Pd(II) catalyst was prepared in a simple way and characterized by XRD, FT-IR, SEM-EDS, XPS and TG, and the ability of this complex to catalyze hydrogenolysis of 1-tetralone into 1,2,3,4-tetrahydronaphthalene was also investigated in the presence of hydrogen. It has been revealed that the catalyst had high catalytic activity for hydrogenolysis of 1-tetralone at ambient temperature and normal pressure of hydrogen. Especially, the hydrogenolysis of 1-tetralone in ethanol solvent gave excellent results and the 100% conversion of 1-tetralone and the 100% selectivity for 1,2,3,4-tetrahydronaphthalene were obtained under optimized reaction conditions. The influences of reaction temperature, reaction time and solvent on the hydrogenolysis of 1-tetralone were also investigated. It has been also revealed that the catalyst was efficient and eco-friendly for the hydrogenolysis of carbonyl that connected with a benzene ring to give corresponding aromatic hydrocarbons.
Synthesis of Ibuprofen Using Silica-Supported Preyssler Nanoparticles as an Eco-Friendly, Inexpensive, and Efficient Catalyst  [PDF]
Ali Gharib,Nader Noroozi Pesyan,Leila Vojdani Fard,Mina Roshani
Organic Chemistry International , 2014, DOI: 10.1155/2014/906801
Abstract: This paper describes an alternative and simple procedure for the synthesis of Ibuprofen using Silica-Supported Preyssler Nanoparticles (H14[NaP5W30O110]/SiO2) (SPNPs), as an eco-friendly, inexpensive, and efficient catalyst. High yields, simplicity of operation, and easy work-up procedure are some advantages of this protocol. Silica-Supported Preyssler Nanoparticles (H14[NaP5W30O110]/SiO2) (SPNPs) offer the advantages of a higher hydrolytic and thermal stability. The salient features of Preyssler’s anion are availability, nontoxicity and reusability. We believe this methodology can find usefulness in organic synthesis. 1. Introduction Ibuprofen was developed by the Boots Pure Chemical Company and then patented in 1961. It is a nonsteroidal anti-inflammatory drug (NSAID) and is marketed under a wide variety of trade names including Advil and Motrin. Ibuprofen is one of several 2-aryl propanoic acids that are currently on the market. Others include ketoprofen, flurbiprofen, and naproxen. The name “ibuprofen” originally came from the name isobutylpropanoicphenolic acid, but this nomenclature has not been used for many years and, in fact, virtually all chemists today are unfamiliar with it. Fortunately, however, the name is still a reasonably good match for the currently accepted name 2-(4-isobutylphenyl)propanoic acid. Ibuprofen ((+/?)2-(4-isobutylphenyl)propionic acid, Figure 1(a)) is one of the most commonly used anti-inflammatory agents. It is considered to be the prototype for the family of synthetic 2-arylpropionic acids, profens, a subclass of the nonsteroidal anti-inflammatory drugs (NSAIDs). In recent years, the profens have come to dominate this therapeutic class. Ibuprofen, for example, is used to treat arthritis, muscular strain, cephalalgia, and so forth. Figure 1 The profens have an asymmetric carbon centre which is attached to a carboxylic acid, a methyl, and an aryl group of varying structures. Some of the available profen drugs are depicted in Figure 1: ibuprofen (a), naproxen (b), ketoprofen (c), and flurbiprofen (d). Ibuprofen is distributed over the counter and naproxen belongs to the top ten of drugs marketed worldwide in 1989 [1]. Ibuprofen is used to relieve the symptoms of a wide range of illnesses including headaches, backache, period pain, dental pain, neuralgia, rheumatic pain, muscular pain, migraine, cold and flu symptoms, and arthritis. NSAIDs exert their pharmacological and toxicological effects primarily by specifically inhibiting the binding of arachidonic acid to the cyclooxygenase subunit of prostaglandin synthetase,
A Simple, Efficient Synthesis of 2-Aryl Benzimidazoles Using Silica Supported Periodic Acid Catalyst and Evaluation of Anticancer Activity  [PDF]
Vyankat A. Sontakke,Sougata Ghosh,Pravin P. Lawande,Balu A. Chopade,Vaishali S. Shinde
ISRN Organic Chemistry , 2013, DOI: 10.1155/2013/453682
Abstract: A new, efficient method for the synthesis of 2-aryl substituted benzimidazole by using silica supported periodic acid (H5IO6-SiO2) as a catalyst has been developed. The salient feature of the present method includes mild reaction condition, short reaction time, high yield and easy workup procedure. The synthesized benzimidazoles exhibited potent anticancer activity against MCF7 and HL60 cell lines. 1. Introduction The benzimidazole nucleus is commonly present in a large number of natural products as well as pharmacologically active compounds [1]. It shows a wide spectrum of biological and pharmacological properties such as antifungal [2], antimicrobial [3], anthelmintic [4, 5], antiviral [6, 7], topoisomerase inhibition [8] and anticancer activities [9]. Some of their derivatives are marketed as antifungal drug (Carbendazim) [10], anthelmintic drug (Mebendazole and Thiabendazole) [11], antipsychotic drug (Pimozide) [12] and antiulcer agent (Omeprazole) [13]. Owing to their interesting pharmacological properties, great attention has been paid to the synthesis of benzimidazoles. Two main synthetic methods were well known in the literature. The most common method is direct condensation of 1,2-phenylenediamine and carboxylic acids [14, 15] or their derivatives [16], that require strong acidic conditions and sometimes need high temperature or the use of microwave [17]. The other synthetic route involves a two-step procedure that includes the cyclo-dehydrogenation of aniline Schiff’s bases, which are often generated in situ from the condensation of 1,2-phenylenediamines and aldehydes [18], followed by oxidation with stoichiometric amount of oxidants, such as MnO2 [19], Oxone [20], NaHSO3 [21, 22], I2/KI/K2CO3/H2O [23] or catalytic use of CAN [24] and AIKIT-5 [25]. More recently, 2-alkyl substituted benzimidazoles are synthesized by using hexafluorophosphoric acid under microwave condition [26]. There is renewed interest in the silica supported catalyzed reactions [27]. These reactions have relatively shorter reaction time with high yield and cleaner chemistry. Moreover, the catalyst is easily separated from reaction mixture by simple filtration. There are very few reports involving solid supported catalyzed reaction for synthesis of benzimidazole derivatives. Jacob et al. [28] synthesized 1,2-disubstituted benzimidazoles by silica supported ZnCl2 catalyst that was found to be of poor yield. Patil et al. [29] developed a method for synthesis of 2-alkyl benzimidazoles using silica supported HBF4. Paul and Basu [30] described the synthesis of 1,2-disubstituted
Oxidative Debromination and Degradation of Tetrabromo-bisphenol A by a Functionalized Silica-Supported Iron(III)-tetrakis(p-sulfonatophenyl)porphyrin Catalyst  [PDF]
Qianqian Zhu,Yusuke Mizutani,Shohei Maeno,Masami Fukushima
Molecules , 2013, DOI: 10.3390/molecules18055360
Abstract: Tetrabromobisphenol A (TBBPA), a commonly used brominated flame retardant, also functions as an endocrine disruptor. Thus, the degradation of TBBPA has attracted considerable interest among the scientific community. Iron(III)-porphyrin complexes are generally regarded as “green” catalysts and have been reported to catalyze the efficient degradation and dehalogenation of halogenated phenols in environmental wastewaters. However, they are quickly deactivated due to self-degradation in the presence of an oxygen donor, such as KHSO 5. In the present study, an iron(III)-tetrakis ( p-sulfonatophenyl)-porphyrin (FeTPPS) was immobilized on imidazole-modified silica (FeTPPS/IPS) via coordination of the Fe(III) with the nitrogen atom in imidazole to suppress self-degradation and thus enhance the catalyst reusability. The oxidative degradation and debromination of TBBPA and the influence of humic acid (HA), a major component in leachates, on the oxidation of TBBPA was investigated. More than 95% of the TBBPA was degraded in the pH range from 3 to 8 in the absence of HA, while the optimal pH for the reaction was at pH 8 in the presence of HA. Although the rate of degradation was decreased in the presence of HA, over 95% of the TBBPA was degraded within 12 h in the presence of 28 mg-C L ?1 of HA. At pH 8, the FeTPPS/IPS catalyst could be reused up to 10 times without any detectable loss of activity for TBBPA for degradation and debromination, even in the presence of HA.
Alumina/silica aerogel with zinc chloride as an alkylation catalyst
ALEKSANDAR M. ORLOVIC,DJORDJE T. JANACKOVIC,SASA DRMANIC,ZORICA MARINKOVIC
Journal of the Serbian Chemical Society , 2001,
Abstract: The alumina/silica with zinc chloride aerogel alkylation catalyst was obtained using a one step sol-gel synthesis, and subsequent drying with supercritical carbon dioxide. The aerogel catalyst activity was found to be higher compared to the corresponding xerogel catalyst, as a result of the higher aerogel surface area, total pore volume and favourable pore size distribution. Mixed Al O Si bonds were present in both gel catalyst types. Activation by thermal treatment in air was needed prior to catalytic alkylation, due to the presence of residual organic groups on the aerogel surface. The optimal activation temperature was found to be in the range 185 225°C, while higher temperatures resulted in the removal of zinc chloride from the surface of the aerogel catalyst with a consequential decrease in the catalytic activity. On varying the zinc chloride content, the catalytic activity of the aerogel catalyst exhibited a maximum. High zinc chloride contents decreased the catalytic activity of the aerogel catalyst as the result of the pores of the catalyst being plugged with this compound, and the separation of the alumina/silica support into Al-rich and Si-rich phases. The surface area, total pore volume, pore size distribution and zinc chloride content had a similar influence on the activity of the aerogel catalyst as was the case of xerogel catalyst and supported zinc chloride catalysts.
Synthesis of Silica Fiber Supported Cu/ZnO Catalyst and Design of a High Selective Steam Reforming Methanol Reactor without Carrier Gas
Ahmad Rifqy Marully,Minsahril Bukit,Khairurrijal,Mikrajuddin Abdullah
Jurnal Nanosains & Nanoteknologi , 2010,
Abstract: Nanocrytalline catalyst of Cu/ZnO supported by silicon dioxide (SiO2) fibers has been synthesized by a simple heating of a mixture of metallic nitrous solution, polyethylene glycol solution and SiO2 fibers at temperatures above the decomposition temperature of the PEG. A vertical steam reforming reactor to convert a mixture of water and methanol without using of carrier gas has also been designed using the prepared catalyst. The reactor consisted of an evaporation section at the bottom and reaction section at the top. The steam generated at the bottom moved up automatically to the reaction section because low mass density. Although the conversion efficiency from methanol and water into hydrogen was not high enough, however, the reactor was very selective. The concentration of hydrogen gas produced was above 99% while the poisonous CO gas was undetected.
SILICA SUPPORTED PERCHLORIC ACID: AN EFFICIENT CATALYST FOR THE SYNTHESIS OF CIS-ISOQUINOLONIC ACIDS Siliciumdioxid PERCHLORS URE: AN effizienter Katalysator für die Synthese von cis-ISOQUINOLONIC S UREN  [cached]
JAISHREE L.SOMWANSHI, N.D.SHINDE, B.A.ARBAD, MAZHAR FARUQUI
Heterocyclic Letters , 2013,
Abstract: An efficient preparation of cis-isoquinolonic acids employing a one-pot condensation reaction of homopthalic anhydride, aromatic aldehydes and anilines using silica supported perchloric acid is described. Short reaction times, high yields with high purity, mild reaction conditions and recyclability of supported catalyst are the features of this protocol.
The Influence of Mixed Activators on Ethylene Polymerization and Ethylene/1-Hexene Copolymerization with Silica-Supported Ziegler-Natta Catalyst  [PDF]
Nichapat Senso,Supaporn Khaubunsongserm,Bunjerd Jongsomjit,Piyasan Praserthdam
Molecules , 2010, DOI: 10.3390/molecules15129323
Abstract: This article reveals the effects of mixed activators on ethylene polymerization and ethylene/1-hexene copolymerization over MgCl2/SiO2-supported Ziegler-Natta (ZN) catalysts. First, the conventional ZN catalyst was prepared with SiO2 addition. Then, the catalyst was tested for ethylene polymerization and ethylene/1-hexene (E/H) co-polymerization using different activators. Triethylaluminum (TEA), tri-n-hexyl aluminum (TnHA) and diethyl aluminum chloride (DEAC), TEA+DEAC, TEA+TnHA, TnHA+ DEAC, TEA+DEAC+TnHA mixtures, were used as activators in this study. It was found that in the case of ethylene polymerization with a sole activator, TnHA exhibited the highest activity among other activators due to increased size of the alkyl group. Further investigation was focused on the use of mixed activators. The activity can be enhanced by a factor of three when the mixed activators were employed and the activity of ethylene polymerization apparently increased in the order of TEA+ DEAC+TnHA > TEA+DEAC > TEA+TnHA. Both the copolymerization activity and crystallinity of the synthesized copolymers were strongly changed when the activators were changed from TEA to TEA+DEAC+TnHA mixtures or pure TnHA and pure DEAC.? As for ethylene/1-hexene copolymerization the activity apparently increased in the order of TEA+DEAC+TnHA > TEA+TnHA > TEA+DEAC > TnHA+DEAC > TEA > TnHA > DEAC. Considering the properties of the copolymer obtained with the mixed TEA+DEAC+TnHA, its crystallinity decreased due to the presence of TnHA in the mixed activator. The activators thus exerted a strong influence on copolymer structure. An increased molecular weight distribution (MWD) was observed, without significant change in polymer morphology.
Silica supported perchloric acid: an efficient catalyst for the synthesis of 14-aryl-14H-dibenzo[a,i]xanthene-8,13-diones
Wu, Li Qiang;Wu, Yan Fang;Yang, Chun Guang;Yang, Li Min;Yang, Li Juan;
Journal of the Brazilian Chemical Society , 2010, DOI: 10.1590/S0103-50532010000500025
Abstract: the condensation of β-naphthol with aromatic aldehydes and 2-hydroxynaphthalene-1,4-dione in presence of silica supported perchloric acid under solvent-free media to afford the corresponding 14-aryl-14h-dibenzo[a,i]xanthene-8,13-diones in excellent yields and short reaction times is described. the reaction work-up is very simple and the catalyst can be easily separated from the reaction mixture and reused several times in subsequent reactions.
Silica gel Catalyzed Synthesis of Quinophthalone Pigments Under Solvent-Free Conditions Using Microwave Irradiation  [PDF]
Hossein Loghmani-Khouzani,Majid M. Sadeghi,J. Safari
Molecules , 2002, DOI: 10.3390/70200135
Abstract: Condensations of anhydrides and quinaldine derivatives are accelerated by microwave irradiation under solvent free conditions in the presence of silica gel as catalyst.
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