86459-85-0Relevant academic research and scientific papers
Copper(II) tetrafluoroborate as a novel and highly efficient catalyst for acetal formation
Kumar, Raj,Chakraborti, Asit K.
, p. 8319 - 8323 (2005)
Commercially available copper(II) tetrafluoroborate hydrate has been found to be a highly efficient catalyst for dimethyl/diethyl acetal formation in high yields from aldehydes and ketones by reaction with trimethyl/triethyl orthoformate at room temperature and in short period. Acetalisation was carried out under solvent-free conditions with electrophilic aldehydes/ketones. For weakly electrophilic aldehydes/ketones (e.g., benzaldehyde, cinnamaldehyde and acetophenone) and for aldehydes having a substituent that can coordinate with the catalyst, the corresponding alcohol was used as solvent.
Preparation of acetals from aldehydes and alcohols under basic conditions
Grabowski, Jakub,Granda, Jaros?aw M.,Jurczak, Janusz
, p. 3114 - 3120 (2018/05/17)
A new, simple protocol for the synthesis of acetals under basic conditions from non-enolizable aldehydes and alcohols has been reported. Such reactivity is facilitated by a sodium alkoxide along with a corresponding trifluoroacetate ester, utilizing formation of sodium trifluoroacetate as a driving force for acetal formation. The usefulness of this protocol is demonstrated by its orthogonality with various acid-sensitive protecting groups and by good compatibility with functional groups, delivering synthetically useful acetals complementarily to the synthesis under acidic conditions from aldehydes and alcohols.
Phosphorylated Polyacrylonitrile Fibers as an Efficient and Greener Acetalization Catalyst
Xu, Gang,Cao, Jian,Zhao, Yali,Zheng, Lishuo,Tao, Minli,Zhang, Wenqin
supporting information, p. 2565 - 2575 (2017/09/25)
A novel solid acid catalyst (PANEAPF) is developed by immobilization of phosphoric acid on polyacrylonitrile fiber through covalent bonding. Various characterization techniques such as elemental analysis (EA), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), etc. are utilized to confirm the successful grafting and the stability of the fiber catalysts during application. PANEAPF shows high catalytic activity in the acetalization of aldehydes owing to the high utilization efficiency of its functionalized acid sites. In addition, the strong polarity micro-environment in the surface layers of PANEAPF make it highly suitable for catalytic application in both water and alcohol. Furthermore, the fiber catalyst can be applied to the acetalization of aldehydes in a continuous-flow process at room temperature, and shows excellent reactivity and superior recyclability (over 20 times). The many advantages of PANEAPF such as simple preparation, convenient regulation of acid amount, high durability, and eco-friendly process make it very attractive for fixed-bed reactors in the chemical industry.
Tetrafluoroboric acid adsorbed on silica gel as a reusable heterogeneous dual-purpose catalyst for conversion of aldehydes/ketones into acetals/ketals and back again
Kumar, Dinesh,Kumar, Raj,Chakraborti, Asit K.
, p. 1249 - 1256 (2008/12/22)
Aldehydes and ketones can be protected as acetals and ketals by treatment with trimethyl orthoformate (TMOF) or triethyl orthoformate (TEOF) under the catalytic influence of tetrafluoroboric acid adsorbed on silica gel (HBF 4-SiO2). In the case of aldehydes or ketones with highly electrophilic carbonyl group, the reactions are carried out under solvent-free conditions. Aryl alkyl ketones, aryl styryl ketones, aldehydes with weakly electrophilic carbonyl groups, and aldehydes with substituents that can coordinate with the catalyst require the presence of the corresponding alcohol as solvent. For substrates that can be converted into acetals under neat conditions, the acetal formation takes place at a faster rate when the alcohol is used as the solvent. The catalyst can be recovered and reused/recycled four times (after reactivation after each use) without any significant decrease in its catalytic efficiency. The parent aldehydes/ketones are regenerated from the corresponding acetals/ketals in high yields by the treatment with water-alcohol in the presence of HBF4-SiO2 at room temperature for short times. Excellent selectivity was observed during inter- and intramolecular competition studies involving carbonyl substrates with varying electronic and steric environments. Selective acetal formation of benzaldehyde takes place in the presence of 4-(dimethylamino)benzaldehyde, thiophene-2-carboxaldehyde, 1-naphthaldehyde, 9-anthraldehyde, or acetophenone, but 3-nitrobenzaldehyde undergoes selective acetal formation in preference to benzaldehyde. In the case of 4-acetylbenzaldehyde, exclusive acetal formation of the aldehyde carbonyl group occurs. Georg Thieme Verlag Stuttgart.
Perchloric acid adsorbed on silica gel (HClO4-SiO2) as an inexpensive, extremely efficient, and reusable dual catalyst system for acetal/ketal formation and their deprotection to aldehydes/ketones
Kumar, Raj,Kumar, Dinesh,Chakraborti, Asit K.
, p. 299 - 303 (2007/10/03)
Perchloric acid adsorbed on silica gel (HClO4-SiO2) is reported as extremely efficient, inexpensive, and reusable catalyst for dual role for protection of aldehydes/ketones (with trialkyl orthoformates) as acetals/ketals and deprotection (with water-alcohol) to regenerate the carbonyl compounds in high yields at room temperature and in short times. Acetalization/ketalization of electrophilic aldehydes/ketones was carried out under solvent-free conditions. Weakly electrophilic aldehydes/ketones and aldehydes having a substituent that can coordinate with the catalyst, required the corresponding alcohol as solvent. Georg Thieme Verlag Stuttgart.
Ce(3+)-Exchanged Montmorillonite (Ce(3+)-Mont) as a Useful Substrate-Selective Acetalization Catalyst
Tateiwa, Jun-ichi,Horiuchi, Hiroki,Uemura, Sakae
, p. 4039 - 4043 (2007/10/02)
The acetalization of carbonyl compounds with methanol was investigated in the presence of a cation-exchanged montmorillonite (M(n+)-mont; M(n+) = Ce(3+), Zr(4+), Fe(3+), Al(3+), Zn(2+), H(+) and Na(1+).Ce(3+)-mont was found to be the most effective catalyst for substrate-selective acetalization.Cyclohexanones, benzaldehydes, and acid-sensitive 2-furancarboxaldehyde were converted nearly quantitatively to the corresponding acetals in methanol at 25 deg C in the presence of Ce(3+)-mont.The substrates were activated by a Lewis acidic Ce(3+) cation in the interlayer space on the order of 1 kJ mol-1 as measured by FT-IR.The turnover number was estimated to be up to 2.6E3 based on the number of active acid sites in Ce(3+)-mont.
