Solvent free liquid-phase alkylation of phenol over solid sulfanilic acid catalyst

WITHDRAWN: Silica-supported N-alkyl DABCO incorporating different anions: efficient heterogeneous catalysts for the transformation of epoxides to cyclic carbonates

“…The first loss in weight from 27 to 122°C, indicated the loss of adsorbed water from the surface of the silica material. 35 The second and third mass loss events occurred between 190-265°C and 265-440°C, respectively, and were ascribed to the decomposition of the organic phases on the silica surface. Thus, the TGA-DTA provided further proof for the successful immobilization of N-alkyl DABCO on the silica surface.…”

Heterogeneous para-phenylamino sulfonic acid ligand functionalized on MCM-41 derived from rice husk ash: Selective mono-alkylated products of tert-butylation of phenol

“…et al[30] which reported a 95.0% TBA conversion in 9 h instead of 4 h reported herein. When the catalyst amount was increased beyond 50 mg, gradual decrease in overall conversion could be observed, with increasing selectivity Scheme 2.…”

“…S2d, the vibration band at 3228 cm −1 was attributed to the secondary N-H bond which confirms the immobilization of 4-NHPhSO 3 H. The vibration band at 3004 cm −1 was assigned to the C-H aromatic system, whereas the symmetrical and asymmetrical CH 2 units were centered at 2962 and 2804 cm −1 . The C=C of the benzene ring was centered at 1612 and 1452 cm −1 , whereas the band at 1635 cm −1 was attributed to O-H bending mode [30]. A strong absorption band at 1517 cm −1 was due to the formation of new C-N bond between MCM-PrCl and ligand, 4-NH 2 PhSO 3 H by the removal of HCl.…”

“…A strong absorption band at 1517 cm −1 was due to the formation of new C-N bond between MCM-PrCl and ligand, 4-NH 2 PhSO 3 H by the removal of HCl. The S=O bond and -SO 3 stretching band of sulfonic group was assigned to the vibration at 1311, 1162 and 1045 cm −1 [30]. All spectra show bands at 1224, 1080 and 785 cm −1 , which were attributed to the stretching vibrations of the mesoporous silica framework (Si-O-Si) [31].…”

Synthesis and characterization of silica–imidazole mesostructured composite from agricultural biomass

“…The specific surface area of RHA-IMI was found to be 535 m 2 g À1 , while the specific surface area of RHACCl was 633 m 2 g À1 . The decrease in the surface area of RHA-IMI could be due to the immobilization of imidazole, which resulted in some pores being blocked [18]. …”