Synthesis of acetals and ketals catalyzed by tungstosilicic acid supported on active carbon

Abstract

Catalytic activity of activated carbon supported tungstosilicic acid in synthesizing 2-methyl-2-ethoxycarbonylmethyl-1,3-dioxolane, 2,4-dimethyl-2-ethoxycarbonylmethyl-1,3-dioxolane, cyclohexanone ethylene ketal, cyclohexanone 1,2-propanediol ketal, butanone ethylene ketal, butanone 1,2-propanediol ketal, 2-phenyl-1,3-dioxolane, 4-methyl-2-phenyl-1,3-dioxolane, 2-propyl-1,3-dioxolane, 4-methyl-2-propyl-1,3-dioxolane was reported. It has been demonstrated that activated carbon supported tungstosilicic acid is an excellent catalyst. Various factors involved in these reactions were investigated. The optimum conditions found were: molar ratio of aldehyde/ketone to glycol is 1/1.5, mass ratio of the catalyst used to the reactants is 1.0%, and reaction time is 1.0 h. Under these conditions, the yield of 2-methyl-2-ethoxycarbonylmethyl-1,3-dioxolane is 61.5%, of 2,4-dimethyl-2-ethoxycarbonylmethyl-1,3-dioxolane is 69.1%, of cyclohexanone ethylene ketal is 74.6%, of cyclohexanone 1,2-propanediol ketal is 80.1%, of butanone ethylene ketal is 69.5%, of butanone 1,2-propanediol ketal is 78.5%, of 2-phenyl-1,3-dioxolane is 56.7%, of 4-methyl-2-phenyl-1,3-dioxolane is 86.2%, of 2-propyl-1,3-dioxolane is 87.5%, of 4-methyl-2-propyl-1,3-dioxolane is 87.9%.

Direct catalytic conversion of cellulose to liquid straight-chain alkanes

“…The TSA loading on Ru/C aer drying, studied by gravimetric analysis, correlates to the TSA concentration in the pretreatment mixture (Table S1 †), in agreement with the strong adsorption of heteropoly acids on carbon supports. [71][72][73][74][75][76][77] The nal TSA modied catalysts htTSA(2)Ru/C and htTSA(135)Ru/C contain approximately 9 and 27 wt% TSA (on dry basis), respectively. The kinetic proles are presented in Fig.…”

tert‐butanol and hydrogen peroxide react over Amberlyst‐15 to form tert‐butyl hydroperoxide

“…The incipient wetness impregnation technique is applied for supported HPA. In the first step of the Cs 2.5 H 0.5 PW 12 O 40 /SiO 2 synthesis, we impregnated the tungstophosphoric acid on silica powder, dried it at 110 C for 4 h, and calcined it at 300 C for 6 h. In the same way, we impregnated the caesium carbonate on the HPA/SiO 2 , dried it at 110 C, and calcined it at 300 C. [27] For the Cs 2.5 H 0.5 PW 12 O 40 /C catalyst, we followed the method reported by Yang et al [28] First, we impregnated the Cs 2.5 H 0.5 PW 12 O 40 salt for 6 h. Then, the black solid was washed in distilled water and dried at 105 C for 24 h. We applied the same impregnation method for the (Cs 2.5 H 0.5 PW 12 O 40 )/Amb-15 catalyst without prior treatment of Amberlyst-15. [29] To determine the concentration of Brønsted acid sites in porous catalyst, we titrated 0.05 g Amberlyst-15 suspended and stirred in 5 mL of distilled water and 0.5 mL of NaOH (0.1 M) with HCl (0.1 M) in presence of phenolphthalein as indicator.…”

Estudio teórico de la síntesis de hemiacetales catalizada por ácidos de Lewis

“…Además, se han llevado a cabo estudios experimentales (Trifoi et al, 2016), (Ferreira et al, 2019); trabajos teóricos (Azofra et al, 2012) sobre síntesis de hemiacetales y estudios donde dicha reacción puede ser catalizada por medio de una base (Funderburk et al, 1978), (Grabowski et al, 2018) de un ácido de Brönsted (Dong et al, 2018), (Yang et al, 2005), de un ácido de…”