The novel solvent dimethyl sulfoxide (DMSO)/tetrabutylammonium fluoride trihydrate (TBAF . 3H(2)O) was studied for acetylation of linters cellulose. In order to control the degree of substitution (DS), acetylation of the macromolecule was carried out at different reaction time and temperature, molar ratio of reactants, as well as under variation of the concentration of TBAF . 3H(2)O in solution. Cellulose acetate (CA) was accessible with DS ranging from 0.43 to 2.77. The change in concentration of TBAF . 3H(2)O in DMSO showed a strong influence on DS. The most appropriate reaction conditions for acetylation of linters cellulose regarding maximal DS were evaluated. The structure of the CA was characterized by means of FTIR and NMR spectroscopy. The solubility of the CA depends not only on the DS but also on the reaction conditions applied, indicating a different distribution of acetate moieties both within and between polymer chains.
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http://dx.doi.org/10.1002/mabi.200400088 | DOI Listing |
J Org Chem
June 2024
School of Applied Chemical Engineering, Lanzhou Petrochemical University of Vocational Technology, No. 1 Shandan Street, Lanzhou 730060, P. R. China.
A metal-free, mild, and efficient method for the synthesis of amides has been developed from the amination of aldehydes with hydroxylamines promoted by TBAF·3HO in the presence of KOH. Control experiments showed that the nitrone was the intermediate of this amination. By this method, a series of amides, biologically active compounds bebenil and a COX inhibitor were obtained in moderate to good yields.
View Article and Find Full Text PDFCarbohydr Polym
April 2024
Jiangsu Co-Innovation Center for Efficient Processing and Utilization of Forest Resources and International Innovation Center for Forest Chemicals and Materials, Nanjing Forestry University, Nanjing 210037, China. Electronic address:
Org Lett
May 2019
Institute of Organic Chemistry , Justus Liebig University, Heinrich-Buff-Ring 17 , 35392 Giessen , Germany.
A new Kinugasa reaction protocol has been elaborated for the one-pot synthesis of 4-substituted β-lactams utilizing calcium carbide and nitrone derivatives. Calcium carbide is thereby activated by TBAF·3HO in the presence of CuCl/NMI. The ease of synthesis and use of inexpensive chemicals provides rapid access of practical quantities of β-lactams exclusively substituted at position 4.
View Article and Find Full Text PDFOrg Lett
February 2016
Shanghai Key Lab of Chemical Assessment and Sustainability, Department of Chemistry, Tongji University, 1239 Siping Road, Shanghai 200092, P. R. China.
A direct fluorination of 1-(2,2-dibromovinyl)benzene derivatives using wet tetra-n-butylammonium fluoride (TBAF·3H2O) as either a base or a fluorine source in toluene was accomplished, which provided (Z)-1-(2-bromo-1-fluorovinyl)benzene compounds in up to 81% yields with high regioselectivities. This reaction results strongly depend upon the reaction conditions. The mechanism of this reaction was investigated as well.
View Article and Find Full Text PDFOrg Lett
June 2015
⊥Institute of Organic Chemistry, Justus-Liebig University, Heinrich-Buff-Ring 58, 35392 Giessen, Germany.
The fluoride-assisted ethynylation of ketones and aldehydes is described using commercially available calcium carbide with typically 5 mol % of TBAF·3H2O as the catalyst in DMSO. Activation of calcium carbide by fluoride is thought to generate an acetylide "ate"-complex that readily adds to carbonyl groups. Aliphatic aldehydes and ketones generally provide high yields, whereas aromatic carbonyls afford propargylic alcohols with moderate to good yields.
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