- Alkylation reactions of potassium carboxylates supported on alumina: Comparison between ball-milling, impregnation and dispersion procedures
-
Potassium carboxylate alkylation by n-bromooctane on neutral alumina in "dry media" under microwave irradiation was studied for different methods of preparation of salt-support powder. Mechanical milling and impregnation techniques led to equivalent yields, much higher than those obtained through dispersion. The first method avoids using solvents and subsequent drying of powders. Crystallographic and granulometric studies of the resulting powders were performed to ascertain the results.
- Gasgnier, Michel,Szwarc, Henri,Petit, Alain,Nahmias, Jean,Loupy, Andre
-
-
Read Online
- ORGANIC SYNTHESES WITHOUT SOLVENT: BASE-CATALYSED ESTER INTERCHANGE
-
Ester interchange of methyl or ethyl carboxylic esters by primary or secondary alcohols is carried out effectively when solid-liquid phase transfer catalysis (PTC) is achieved in the absence of added organic solvent.Vinyl and isopropenyl acetates undergo ester interchange, even in the absence of PTC catalyst, with primary alcohols and phenols.
- Barry, Jean,Bram, Georges,Petit, Alain
-
-
Read Online
- Synthesis of biolubricants using sulfated zirconia catalysts
-
Synthesis of biomass-derived lubricants via esterification, transesterification, and simultaneous reactions of both was studied by using sulfated zirconia catalysts. Soybean oil or free fatty acids derived from soybean oil were used as a biomass-derived resource for the synthesis of biolubricants. Long chain alcohols (carbon number ≥ 8) or neo-polyols (e.g., 2,2-diethyl-1,3-propanediol, trimethylol propane, pentaerythritol) were used as co-reactants. The structure of the alcohol significantly affected the conversion and yield for the esterification with oleic acid. The esters produced showed kinematic viscosity and viscosity index comparable to commercial lubricants. Various sulfated zirconia catalysts were prepared and were characterized by X-ray diffraction, NH3 temperature-programmed desorption, Brunauer-Emmett-Teller isotherm, and tested for esterification. The type of zirconium precursor demonstrated a significant effect on the physical property of the catalyst and its catalytic activity. Interestingly, esters with fully saturated hydrocarbon chains were synthesized from unsaturated free fatty acids regardless of the absence of hydrogen gas. The sulfated zirconia could be recycled for up to five repeated reactions without any degradation. The effects of reaction time and temperature were also investigated.
- Oh, Jinho,Yang, Sungeun,Kim, Chanyeon,Choi, Inchang,Kim, Jae Hyun,Lee, Hyunjoo
-
-
Read Online
- A novel poly(p-styrenesulfonic acid) grafted carbon nanotube/graphene oxide architecture with enhanced catalytic performance for the synthesis of benzoate esters and fatty acid alkyl esters
-
Considering the issue of low yield in the synthesis of benzoate esters and fatty acid alkyl esters, designing a high catalytic activity composite catalyst is very significant and attractive. In this study, the rational design strategy was used to develop a novel poly(p-styrenesulfonate acid, namely PSSF) grafted multi-walled carbon nanotube composite with graphene oxide nanomaterial (PSSF-mCNTs-GO) using a simple two-step method. FT-IR and Raman spectroscopy, XRD, SEM, TEM, and NH3-TPD were used to characterize the inorganic-organic hybrid material. In particular, the addition of GO remarkably enhanced its catalytic performance in the production of fatty acid alkyl esters (92.16%) and benzoate esters (90.27%), in which the conversion was more than doubled as a result of its strong π-π interaction with the substrate. In addition, PSSF-mCNTs-GO can be separated from the substrate conveniently and still maintained a relatively high catalytic activity even after 6 times recycling, which indicates its rather good reusability. This novel catalyst is promising in the synthesis of biodiesel and benzoate esters.
- Bian, Gang,Jiang, Pingping,Zhang, Weijie,Jiang, Kelei,Hu, Ling,Jian, Zhang,Shen, Yirui,Zhang, Pingbo
-
p. 90757 - 90765
(2015/11/16)
-
- Esterification of free fatty acids (Biodiesel) using nano sulfated-titania as catalyst in solvent-free conditions
-
Nano sulfated titania was tested as catalyst for esterification of free fatty acids, specially methanolic and ethanolic esterification of stearic acid (biodiesels). Factorial design evidenced a positive effect of reaction temperature, amount of catalyst, and solvents on ester conversion. This nano-sized sulfated titania has been prepared by a sol-gel hydrothermal process. This prepared sulfated titania showed high catalytic activity in direct esterification of fatty acids as well as benzoic acids with various alcohols and phenols under solvent-free conditions. This method is of great value because of its environmentally benign character, easy handling, high yields, convenient operation, and green. FT-IR studies are shown that the catalyst can be reused for acylation without loss of catalytic activity.
- Hosseini-Sarvari, Mona,Sodagar, Esmat
-
p. 229 - 238
(2013/05/09)
-
- Esterifications of carboxylic acids and alcohols catalyzed by Al 2(SO4)3 · 18H2O under solvent-free condition
-
Esterifications of equimolar mixture of carboxylic acids and alcohols can be effectively catalyzed by Al2(SO4)3 · 18H2O under solvent-free condition. The esterification catalyzed by Al2(SO4)3 · 18H2O is a promising green method thanks to no need of organic solvent, no pollution, no causticity and ease to handle after reaction. This catalyst is of a low toxicity (usually it is used as purifying agent for drinking water), low-cost compound and is easily separated from the reaction mixture by simple filtration. Moreover, the catalyst can be recycled for the further esterification and the conversion does not evidently decrease.
- Gang, Li,Wenhui, Pang
-
experimental part
p. 559 - 565
(2011/01/07)
-
- Esterification of carboxylic acids with alcohols under microwave irradiation in the presence of zinc triflatet
-
The esterification of aliphatic and aromatic carboxylic acids with various alcohols (1°, 2°, 3°, benzylic) was studied under microwave irradiation in the presence of zinc triflate as catalyst; the reaction times were short and the yield of reactions was good to excellent.
- Shekarriz, Marzieh,Taghipoor, Sohrab,Khalili, Ali Asghar,Jamarani, Mohammad Soleymani
-
p. 172 - 173
(2007/10/03)
-
- Catalytic esterification of alcohols, carboxylic acids and transesterification reactions with cerium(IV) triflate
-
Esterification reactions of alcohols with acetic, chloroacetic, trifluoroacetic, propionic, stearic, and benzoic acids were catalyzed with Ce(OTf)4 in a solvent or under solvent-free conditions with high yields. The formylation and acetylation of primary and secondary alcohols were also easily achieved in ethyl formate and ethyl acetate. A high retention of the configuration was observed in the acetylation and formylation of (-)-menthol.
- Iranpoor, Nasser,Shekarriz, Marzieh
-
p. 455 - 458
(2007/10/03)
-
- The synthesis of esters under microwave irradiation using dry-media conditions
-
Practical and simple techniques are described for using nonmodified domestic microwave ovens as safe and convenient laboratory devices to obtain numerous esters.High pressures are avoided by conducting reactions with reactants impregnated on solid mineral supports in "dry media" or by phase transfer catalysis (PTC) in the absence of organic solvents.Two kinds of microwave effects are involved: (1) displacement of the equilibrium by evaporation of volatile polar molecules (water or alcohols) in esterfications and transesterfications; (2) acceleration of ionic reactions in carboxylate alkylations.As solvents are avoided, there is no need for sealed vessels and water separators.
- Loupy, Andre,Petit, Alain,Ramdani, Mohamed,Yvanaeff, Celine,Majdoub, Mustapha,et al.
-
-
- LACTONISIERUNG VON MAKROLID-SECOSAEUREN MIT "PUSH-PULL ACETYLENEN"
-
A highly efficient method for the macrolactonization of seco-acids is described.Seco-acids are converted into stable enolesters 3 by the acetylene 1, which are cyclized under proton or Lewis acid catalysis.This new method has been successfully applied to the lactonization of the 7-epi-brefeldin A seco-acids 8a, b.
- Gais, H.-J.
-
p. 273 - 276
(2007/10/02)
-