scholarly journals Acid-Catalyzed Esterification of Betaines: Theoretical Exploration of the Impact of the Carbon Chain Length on the Reaction Mechanism

Physchem ◽  
2021 ◽  
Vol 1 (3) ◽  
pp. 288-296
Author(s):  
Richail Dubien Moulandou-Koumba ◽  
Frédéric Guégan ◽  
Jean-Maurille Ouamba ◽  
Samuel N’Sikabaka ◽  
Gilles Frapper

Betaine derivatives, especially esters, are compounds of interest for the development of a more sustainable fine chemistry, as they are widely available from biomass and currently produced as side-products from various industries (among which, sugar production). In this publication, we studied the impact of carbon chain length on three considered reaction mechanisms for the esterification of (CH3)3N(CH2)nCO2 betaine (n = 1, 2, 3) with glycerol under acid catalysis. DFT calculations show that the mechanism proposed by Bachmann–Frapper et al. may also be active here, but it can interestingly be seen as an avatar of the former proposition by Watson. Conversely, Ingold’s proposition is in this case too energetically prevented. Overall, lower activation barriers and higher reaction exergonicity are reported, suggesting esterification of longer carbon-chain based betaines is more readily achieved.

2021 ◽  
pp. 117119
Author(s):  
Mansoor Ul Hassan Shah ◽  
Ambavaram Vijaya Bhaskar Reddy ◽  
Suzana Yusup ◽  
Masahiro Goto ◽  
Muhammad Moniruzzaman

2021 ◽  
Author(s):  
Liwen Zeng ◽  
Kong-qiu Hu ◽  
Zhi-wei Huang ◽  
Lei Mei ◽  
Xianghe Kong ◽  
...  

Herein, we report a new uranyl-organic polyhedron U4L4 (L=BTPCA) assembled from uranyl and a semirigid tritopic ligand. By adjusting the carbon chain length of the organic templates, two complexes can...


2014 ◽  
Vol 82 ◽  
pp. 172-180 ◽  
Author(s):  
En-Jun Gao ◽  
Hong Fu ◽  
Ming-Chang Zhu ◽  
Chi Ma ◽  
Shi-Kai Liang ◽  
...  

Pharmaceutics ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 467
Author(s):  
Shahla S. Smail ◽  
Mowafaq M. Ghareeb ◽  
Huner K. Omer ◽  
Ali A. Al-Kinani ◽  
Raid G. Alany

Nanoemulsions (NE) are isotropic, dispersions of oil, water, surfactant(s) and cosurfactant(s). A range of components (11 surfactants, nine cosurfactants, and five oils) were investigated as potential excipients for preparation of ketorolac tromethamine (KT) ocular nanoemulsion. Diol cosurfactants were investigated for the effect of their carbon chain length and dielectric constant (DEC), Log P, and HLB on saturation solubility of KT. Hen’s Egg Test—ChorioAllantoic Membrane (HET-CAM) assay was used to evaluate conjunctival irritation of selected excipients. Of the investigated surfactants, Tween 60 achieved the highest KT solubility (9.89 ± 0.17 mg/mL), followed by Cremophor RH 40 (9.00 ± 0.21 mg/mL); amongst cosurfactants of interest ethylene glycol yielded the highest KT solubility (36.84 ± 0.40 mg/mL), followed by propylene glycol (26.23 ± 0.82 mg/mL). The solubility of KT in cosurfactants was affected by four molecular descriptors: carbon chain length, DEC, log P and HLB. KT solubility was directly proportional to DEC and the HLB yet, inversely proportional to carbon chain length and log P. All surfactants, except Labrasol ALF, were non-irritant. The majority of cosurfactants were slightly irritant, butylene glycol was a moderate irritant, pentylene and hexylene glycols were strong irritants. These findings will inform experiments aimed at developing NE formulations for ocular administration of KT.


1996 ◽  
Vol 1996 ◽  
pp. 98-98
Author(s):  
B M L McLean ◽  
R W Mayes ◽  
F D DeB Hovell

Alkanes occur naturally in all plants, although forage crops tend to have higher alkane contents than cereals. N-alkanes have odd-numbered carbon chains. They are ideal for use as markers in feed trials, because, they are inert, indigestible and naturally occurring, and can be recovered in animal faeces. Synthetic alkanes (even-numbered carbon chains) are available commercially and can also used as external markers. Dove and Mayes (1991) cite evidence indicating that faecal recovery of alkanes in ruminants increases with increasing carbon-chain length. Thus the alkane “pairs” (e.g. C35 & C36, and C32 & C33) are used in calculating intake and digestibility because they are long chain and adjacent to each other. However, recent work by Cuddeford and Mayes (unpublished) has found that in horses the faecal recovery rates are similar regardless of chain lengths.


Sign in / Sign up

Export Citation Format

Share Document