540-88-5Relevant academic research and scientific papers
Esterification of tert-butanol and acetic acid by silicotungestic acid catalyst supported on bentonite
Jin, Jian-Zhong,Sun, Na-Bo
, p. 4441 - 4443 (2013)
A series of solid acid catalysts were synthesized by incipient wetness impregnation method by varying the wt % of silicotungstic acid on bentonite. Silicotungestic acid supported on bentonite was used to catalytic synthesis of tert-butyl acetate with acetic acid and tert-butyl alcohol. The main reaction parameters such as silicotungstic acid loading on bentonite, the amount of catalyst, molar ratio of reactants, reaction temperature and reaction time have been investigated. The optimum conditions were determined as follows: silicotungstic acid loading on bentonite 25 wt %, catalyst 0.7 g, mole ratio of tert-butanol to acetic acid 1:1.1, reaction temperature 110 °C and reaction time 2 h. The esterification yield of tert-butyl acetate was about 87.2 %. The catalyst could be used repeatedly for many times without distinct loss in activity.
UNE NOUVELLE CLASSE D'INHIBITEURS IRREVERSIBLES: LES SULFINAMOYLESTERS PRECURSEURS DE SULFINES.
Baltas, Michel,Cazaux, Louis,Gorrichon-Guigon, Liliane,Maroni, Pierre,Tisnes, Pierre
, p. 4447 - 4450 (1985)
Tert-butyl N-aryl sulfinamoyl acetates are hydrolyzed in aqueous basic media following a bimolecular elimination process, via anintermediate sulfine species.The use of sulfinamoyl compounds as irreversible inactivators for zinc-metalloenzymes is emphasized.
Dehydrogenative ester synthesis from enol ethers and water with a ruthenium complex catalyzing two reactions in synergy
Ben-David, Yehoshoa,Diskin-Posner, Yael,Kar, Sayan,Luo, Jie,Milstein, David,Rauch, Michael
supporting information, p. 1481 - 1487 (2022/03/07)
We report the dehydrogenative synthesis of esters from enol ethers using water as the formal oxidant, catalyzed by a newly developed ruthenium acridine-based PNP(Ph)-type complex. Mechanistic experiments and density functional theory (DFT) studies suggest that an inner-sphere stepwise coupled reaction pathway is operational instead of a more intuitive outer-sphere tandem hydration-dehydrogenation pathway.
Green, efficient and economical coal fly ash based phosphomolybdic acid catalysts: preparation, characterization and application
Malpani, Sakshi Kabra,Goyal, Deepti,Katara, Stuti,Rani, Ashu
, p. 3017 - 3034 (2021/02/26)
Abstract: Cost-effective, efficient and green solid acid catalysts have been synthesized by incipient wetness impregnation of various weight fractions of phosphomolybdic acid (5, 10, 15 and 25 wt. %) on mechanically and thermally activated coal fly ash. N2 adsorption–desorption, XRD, FT-IR, SEM, SEM–EDX, TEM, TGA, UV–Vis DRS, solid state 31P MAS NMR were used for characterization of as synthesized catalysts. Catalytic active sites were developed on inert surface of coal fly ash by using various activation techniques whose performance was assessed over a series of acylation of various aliphatic alcohols. For rapid and higher catalytic activity, reactions were conducted in microwave heating mode. Impregnation of phosphomolybdic acid generates Lewis acidic sites on coal fly ash surface as inferred by pyridine adsorbed FT-IR studies which were then utilized in acylation reactions. Various reaction parameters like weight fraction of catalysts, molar ratio of reactants, time, temperature, etc. were optimized for attaining highest conversion %. The catalyst with 15 wt. % of phosphomolybdic acid was found to be more efficient and could be recycled up to five reaction cycles with analogous conversion %. Negligible leaching of catalyst was confirmed by hot filtration test. This work suggests an alternative approach for valorisation of industrial solid waste, coal fly ash in development of innovative, economical solid catalysts. Graphic abstract: [Figure not available: see fulltext.].
Molybdenum-modified mesoporous SiO2as an efficient Lewis acid catalyst for the acetylation of alcohols
Hlatshwayo, Xolani S.,Ndolomingo, Matumuene Joe,Bingwa, Ndzondelelo,Meijboom, Reinout
, p. 16468 - 16477 (2021/05/19)
A suitable, expeditious and well-organized approach for the acetylation of alcohols with acetic anhydride in the presence of 5%MoO3-SiO2 as an optimum environmentally benign heterogeneous catalyst was developed. The high surface area obtained for 5%MoO3-SiO2, 101 m2 g-1 compared to other catalysts, 22, 23, and 44 m2 g-1 for 5%WO3-ZrO2, 5%WO3-SiO2, and 5%MoO3-ZrO2, respectively, appears to be the driving force for better catalytic activity. Amongst the two dopants used, molybdenum oxide is the better dopant compared to its tungsten oxide counterpart. High yields of up to 86% were obtained with MoO3 doping while WO3 containing catalysts did not show any activity. Other reaction parameters such as reactor stirring speed, and solvent variation were studied and revealed that the optimum stirring speed is 400 rpm and cyclohexane is the best solvent. Thus, the utilization of affordable and nontoxic materials, short reaction times, reusability, and producibility of excellent yields of the desired products are the advantages of this procedure.
Genome mining reveals new bacterial type I Baeyer-Villiger monooxygenases with (bio)synthetic potential
Bianchi, Dario A.,Carabajal, María Ayelén,Ceccoli, Romina D.,Rial, Daniela V.
, (2020/03/19)
Baeyer-Villiger monooxygenases (BVMOs) are oxidorreductases that catalyze the oxidation of ketones in a very selective manner. By genome mining we detected seven putative type I BVMOs in Bradyrhizobium diazoefficiens USDA 110. As we established the phylogenetic relationships among them and with other type I BVMOs, we found out that they belong to different clades of the phylogenetic tree. Thus, we decided to clone and heterologously express five of them. Three of them, each one from a divergent phylogenetic group, were obtained as soluble proteins, allowing us to proceed with their biocatalytic assessment and enzymatic characterization. As to substrate scope and selectivity, we observed a complementary behavior among the three BVMOs. BVMO2 was the more versatile biocatalyst in whole-cell systems while BVMO4 and BVMO5 showed a narrow substrate profile with preference for linear ketones and particular regioselectivity for (±)-cis-bicyclo[3.2.0]hept-2-en-6-one.
Scalable green approach toward fragrant acetates
Puchl'Ová, Eva,Szolcsányi, Peter
, (2020/08/07)
The advantageous properties of ethylene glycol diacetate (EGDA) qualify it as a useful substitute for glycerol triacetate (GTA) for various green applications. We scrutinised the lipase-mediated acetylation of structurally diverse alcohols in neat EGDA furnishing the range of naturally occurring fragrant acetates. We found that such enzymatic system exhibits high reactivity and selectivity towards activated (homo) allylic and non-activated primary/secondary alcohols. This feature was utilised in the scalable multigram synthesis of fragrant (Z)-hex-3-en-1-yl acetate in 70percent yield. In addition, the Lipozyme 435/EGDA system was also found to be applicable for the chemo-selective acetylation of (hydroxyalkyl) phenols as well as for the kinetic resolution of chiral secondary alcohols. Lastly, its discrimination power was demonstrated in competitive experiments of equimolar mixtures of two isomeric alcohols. This enabled the practical synthesis of 1-pentyl acetate isolated as a single product in 68percent yield from the equimolar mixture of 1-pentanol and 3-pentanol.
Cyanation of Anilines to Aryl Nitriles Using tert-Butyl Isocyanide: A Simple and Copper-free Procedure
Chia, Poh Wai,Yong, Fu Siong Julius,Mohamad, Habsah,Kan, Su-Yin
supporting information, p. 939 - 942 (2019/08/21)
In this manuscript, a simple and copper-free procedure for the synthesis of aryl nitrile derivatives from anilines is described. Under the improved protocol, the anilines were reacted with tert-butyl isocyanide under a mild reaction condition without the use of solvents and copper catalyst to synthesize benzonitriles. This copper-free Sandmeyer-type reaction could tolerate a range of anilines bearing different functional groups and also can be conducted even without the exclusion of air. In addition, this method has afforded the aryl nitriles in moderate to good yields (52–81%). The obtained results in this study reveal that the tert-butyl isocyanide as a potential cyanide source for the cyanation reaction.
N-Hydroxyphthalimide (NHPI) Promoted Aerobic Baeyer-Villiger Oxidation in the Presence of Aldehydes
Wang, Lingyao,Wang, Yongtao,Du, Renfeng,Dao, Rina,Yuan, Haoran,Liang, Cheng,Yao, Jia,Li, Haoran
, p. 4961 - 4966 (2018/10/02)
Metal-free aerobic Baeyer-Villiger (BV) oxidation of ketones to lactones or esters in the presence of aldehydes promoted by N-hydroxyphthalimide (NHPI) has been developed. The reaction proceeded under mild conditions with excellent selectivity and high yields. Compared with the methods that use metal complexes as catalysts, this strategy not only showed good environmental advantages, but also increased aldehyde efficiency up to 84 %. Control experiments indicated that NHPI accelerated the oxidation of aldehydes to peroxy acids but did not improve the BV oxidation while peroxy acids were already generated. Peroxy acids generated from aldehydes in situ were the key intermediates, and the phthalimide-N-oxyl radical (PINO) contributed to high aldehyde efficiency by stabilizing the radical species, which are necessary for the chain propagation reactions. This study may offer some useful strategies for new transition metal-free catalytic aerobic oxidation reactions in which aldehydes act as sacrificial agents.
Magnetically recoverable AlFe/Te nanocomposite as a new catalyst for the facile esterification reaction under neat conditions
Alavi, Seyed Jamal,Sadeghian, Hamid,Seyedi, Seyed Mohammad,Eshghi, Hossein,Salimi, Alireza
, (2017/11/23)
In this work, a new Fe3O4/AlFe/Te nanocomposite was synthesized by a one-step sol–gel method. The Fe3O4 magnetic nanoparticles (MNPs) were prepared and then mixed with aluminum telluride (Al2Te3) in an alkali medium to produce the desired catalyst. After characterization of the Fe3O4/AlFe/Te nanocomposite by SEM, TEM, EDS, XRD, and ICP analyses, it was used in the esterification reaction. This heterogeneous catalyst showed high catalytic activity in the esterification of commercially available carboxylic acids with various alcohols to produce the desired esters at high conversions under neat conditions. The Fe3O4/AlFe/Te nanocomposites were separated from the reaction mixture via an external magnet and re-used 8 times without significant loss of catalytic activity.
