15014-25-2Relevant articles and documents
Preparation and characterisation of amorphous mesoporous aluminophosphate and metal aluminophosphate as an efficient heterogeneous catalyst for transesterification reaction
Vijayasankar,Nagaraju
, p. 1109 - 1116 (2011)
Preparation, characterisation of pure aluminophosphate and aluminophosphate modified with different transition metals (V, Fe, Co Ni & Cu) and their catalytic activity in mono/dibenzyl substituted malonates synthesis are explained. The materials were prepared by the coprecipitation method in the absence of any structure-directing species and characterized for their composition, crystalline nature, total surface acidity, specific surface area pore diameter and pore volume by different techniques. Catalytic activity of the materials was investigated in transesterification of diethylmalonate with benzyl alcohol in liquid phase. Pure aluminophosphate resulted only in benzyl ethylmalonate whereas the incorporation of transition metals favored the formation of both benzyl ethylmalonate and dibenzylmalonate. Catalytic activity parallels the surface acidity and mesoporosity of the catalysts. The effect of the molar ratio of reactants, amount of catalyst, and reaction time on the conversion of diethyl malonate and transester yield has been studied. The highest activity of iron aluminophosphate is attributed to its mesoporous nature with uniform pore size distribution, higher surface acidity and surface area. Further, the scope and generality of iron aluminophosphate as a catalyst in the transesterification was studied using various aliphatic, alicyclic and aromatic alcohols. The catalysts could be recycled by retaining most of its initial activity.
Design of sulphate modified solid acid catalysts for transesterification of diethyl malonate with benzyl alcohol
Minchitha,Hareesh,Venkatesh,Shanty,Nagaraju,Kathyayini
, p. 202 - 214 (2018)
Sulphate ion modified multiwalled carbon nanotubes (S-CNTs), mesoporous carbon (S-MC), zirconia (S-ZrO2), alumina (S-Al2O3) and silica (S-SiO2) were prepared by wet impregnation technique. The physico-chemical properties of the prepared materials were inv
O-Benzylation of Carboxylic Acids Using 2,4,6-Tris(benzyloxy)-1,3,5-triazine (TriBOT) under Acidic or Thermal Conditions
Yamada, Kohei,Yoshida, Saki,Fujita, Hikaru,Kitamura, Masanori,Kunishima, Munetaka
, p. 7997 - 8002 (2015/12/24)
Two methods for the synthesis of benzyl esters from carboxylic acids using the O-benzylating reagent 2,4,6-tris(benzyloxy)-1,3,5-triazine (TriBOT) have been developed. The reactions were conducted either in the presence of a catalytic amount of TfOH at room temperature (acidic conditions) or in the absence of TfOH at 180-230 C (thermal conditions). Interestingly, the O-benzylation of hydroxy carboxylic acids under the two conditions afforded different products: The dibenzylated product under acidic conditions and the hydroxy ester under thermal conditions. In addition to these results, other evidence indicated that the former reaction proceeds through an SN1-type mechanism, and the latter by an SN2-type mechanism. Two methods for the O-benzylation of carboxylic acids using TriBOT have been developed under either acidic or thermal conditions. The O-benzylation of hydroxy carboxylic acids afforded the dibenzylated product under acidic conditions and the hydroxy ester under thermal conditions. The former reaction proceeds through an SN1-type mechanism and the latter by an SN2-type mechanism.
Transesterification of diethyl malonate with benzyl alcohol catalyzed by modified zirconia: Kinetic study
Thimmaraju,Mohamed Shamshuddin,Pratap,Venkatesh
, p. 55 - 65 (2014/05/20)
Zirconia and its modified forms such as 10%Mo(VI)/ZrO2, 10%V(V)/ZrO2, 10%W(VI)/ZrO2 and SO4 2-/ZrO2 were prepared and characterized for their physico-chemical properties such as BET for surface area, NH3-TPD and n-butylamine back titration method for total surface acidity, PXRD technique for crystallinity and ICP-OES technique for elemental analysis. These materials were used as catalysts in liquid phase transesterification reaction of diethyl malonate (DEM) with benzyl alcohol (BA). Optimization of reaction conditions such as reaction time, reaction temperature, weight of the catalyst and molar ratio of reactants were carried out to obtain highest possible transester yield. Dibenzyl malonate (DBM) and benzyl ethyl malonate (BEM) were obtained as major products. Highest total transester yield of (88%) was obtained in the presence of 0.75 g of SZ catalyst at a molar ratio of DEM: BA = 1:3, reaction temperature of 393 K and reaction time 5 h. Kinetic studies were carried out to find out the rate of the reaction and energy of activation values for zirconia catalysts, in order to identify a facile catalyst system for this reaction. A possible reaction mechanism was proposed based on the kinetic data and it was observed that Eley-Rideal mechanism fits well for this reaction. Reactivation and reusability studies of the catalysts were also taken up.