Efficient acetalisation of aldehydes catalyzed by titanium tetrachloride in a basic medium
TL;DR: In this paper, the authors used catalytic amount of Ti(IV) chloride in MeOH in the presence of NH3 or Et3N to achieve the acetalization of aliphatic and aromatic aldehydes.
About: This article is published in Tetrahedron.The article was published on 1998-12-17. It has received 78 citations till now. The article focuses on the topics: Acid catalysis & Titanium tetrachloride.
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TL;DR: The catalytic B-M activity of soluble, substitution-inert, and acidic Cr(NO3)3·9H2O supports the Brønsted-acid effect of the MIL materials.
Abstract: Porous chromium(III) 2-nitro-, 2-amino-, and nonfunctionalized terephthalate (MIL-101Cr) metal organic frameworks are heterogeneous catalysts for diacetal formation from benzaldehyde and methanol (B–M reaction) as well as other aldehydes and alcohols. MIL-101Cr-NO2 obtained by direct reaction between CrO3 and 2-nitro-terephthalate showed the highest activity with 99% conversion in the B–M reaction in 90 min and turnover numbers of 114. The activity decreased in the order MIL-101Cr-NO2 > MIL-101Cr > MIL-101Cr-NH2. Within different samples of nonfunctionalized MIL-101Cr the activity increased with surface area. Methanol gas sorption of the different MIL materials correlates with the BET surface area and pore volume but not with the diacetalization activity. Benzaldehyde adsorption from heptane showed no significant difference for the different MILs. Gas sorption studies of CD3CN to probe for a higher Lewis acidity in MIL-101Cr-NO2 remained inconclusive. A high B–M catalytic activity of wet MIL-101Cr-NO2 exc...
144 citations
TL;DR: Two methods, both of which avoid the use of benzene, have been developed for the formation of acetals of diaryl ketones and the conversion of carbonyl compounds to the corresponding 1,3-dioxolane using ethylene glycol.
Abstract: Acetals are obtained in good yields by treatment of aldehydes and ketones with trialkyl orthoformate and the corresponding alcohol in the presence of 0.1 mol % Bi(OTf)3·4H2O. A simple procedure for...
137 citations
TL;DR: In this article, the protection of carbonyls as cycloacetals or ketals with diols using Bronsted acidic ionic liquid [Hmim]BF4 as catalyst as well as solvent was investigated.
100 citations
96 citations
TL;DR: A mesoporous poly-melamine-formaldehyde (PMF) polymer with a high surface area, good porosity and a high density of amine and triazine functional groups was investigated as a highly efficient hydrogen-bonding catalyst as mentioned in this paper.
76 citations
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Book•
01 Jan 1981
TL;DR: In this article, the most useful groups for the hydroxyl, amino, carboxyl, carbonyl, and sulfhydryl groups are discussed and the chemistry of the classes of these groups, as well as that of individual groups within the class using structures, equations and references.
Abstract: Provides comprehensive information on the most useful protective groups for the hydroxyl, amino, carboxyl, carbonyl, and sulfhydryl groups. Discusses the chemistry of the classes of protective groups, as well as that of the individual protective groups within the class using structures, equations and references. Reactivity Charts for each class of protective group serve as an aid in their appropriate choice and provide estimates of their relative reactivities toward 108 prototype reagents.
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