S. Muthukumaru Pillai

Arylation of acrylonitrile with iodobenzene over Pd/MgO catalyst

Abstract Heck arylation of acrylonitrile with iodobenzene was studied over different 5% Pd supported catalysts. Among these the activity of the catalysts has the following order: Pd/C

Effect of liophilicity of catalyst in cyclic carbonate formation by transesterification of polyhydric alcohols

The effect of catalyst liophilicity is shown in cyclic carbonate formation by transesterification. 1,3-Dichlorodistannoxanes as liophilic transesterification catalysts facilitated cyclic carbonate formation from corresponding 1,2-diols and diethyl carbonate in continuous fashion without isolation of catalyst. Thus 0.5 mol% of catalyst could produce 1,2-glycerol carbonate quantitatively in 2 h with multiple recyclability. The product formed during the reaction was almost quantitative and did not require further purification. Isolation of catalyst at any stage showed retention of its activity and identity.

HZSM-5 catalyzed cyclodehydration of diethylene glycol and its derivatives☆

Abstract Diethylene glycol (DEG) is converted into 1,4-dioxane using HZSM-5 as a catalyst at 205–225°C in the liquid phase. Triethylene glycol, diethylene glycol ethers and PEG gave relatively lower yields of 1,4-dioxane. NH3 adsorption followed by TPD suggests that acidic sites with NH3 desorbing above 350°C are responsible for the cyclodehydration of DEG and its derivatives. Correlation of activity and efficiency of the catalyst with density of strongly acidic sites suggests that both cyclodehydration and deactivation of the catalysts take place simultaneously.

Disproportionation, isomerization and de-tert-butylation of 2,6-di-tert-butylphenol catalyzed by H-MCM-41

Mesoporous H-MCM-41 is an efficient catalyst for conversion of 2,6-di-tert-butylphenol to 2-tert-butylphenol, 2,4,6-tri-tert-butylphenol, 2,4-di-tert-butylphenol and 4-tert-butylphenol besides di- and tri-isobutylene in solvent free conditions. At low temperature (100 °C) and shorter reaction times 2-tert-butylphenol and 2,4,6-tri-tert-butylphenol are major products whereas at high temperature (180 °C) 4-tert-butylphenol is the most favoured product. H-MCM-41 steamed for 6 h at 520 °C was found to be the most active catalyst with maximum turnover of the products.

Single wavelength check isocratic reverse phase HPLC method for fast and direct estimation of alkyl aromatic oxidation products

An isocratic, reverse phase liquid chromatographic method has been developed for the quantitative determination of p-xylene oxidation products. The method represents a direct and fast analytical procedure to determine the assay. Separation is achieved on Waters μ-Bondapak C18, 300 mm × 3.9 mm × 10 μm column in a single wavelength 230 nm. The method has been validated with respect to linearity, limit of quantification, accuracy and robustness. Critical impurity 4-carboxy benzaldehyde (4-CBA) is found to be within the limit of quantification, 8 ppm, accuracy 97–98%, recovery 98 to 101% and resolution 1.97 from the closest peak. The sample solution is stable and can be used safely within 48 h. The method is verified by real sample reaction mixture.

Cyclodehydration of Some 1,n-Diols Catalysed by Sulfated Zirconia

Sulfated zirconia, a solid acid, is found to be a good catalyst in the cyclodehydration of several diols.