Application In Esterification Research Articles

Synthesis of sulphonated mesoporous phenolic resins and their application in esterification and asymmetric aldol reactions

Mesoporous phenolic resins were functionalized with sulphonic acid groups by four different types of sulphonation procedures: (i) direct sulphonation on the aromatic ring, (ii) alkyl sulphonation of the aromatic ring, and functionalizations of the phenolic hydroxyl surface by using an aryl silane, 2-(4-chlorosulphonylphenyl)ethyl trichlorosilane (iii) or a propyl silane, 3-mercaptopropyltrimethoxysilane (iv). The highest acidity loadings were obtained through direct sulphonation with fuming sulphuric acid (1.90 mmol H+ g−1) or chlorosulphonic acid (1.31 mmol H+ g−1) and these materials showed the highest conversion (97+ %) in Fischer esterification of acetic acid with propanol. However, the alkyl sulphonic groups, obtained through sulphonation procedure (ii) showed the highest stability in terms of maintenance of their acidity after use in consecutive catalytic runs or leaching treatments. This was demonstrated both through evaluation of the regenerated catalysts in a consecutive esterification run and during a leaching resistance test in aqueous medium. Moreover, the developed sulphonated mesoporous phenolic resins are presented as novel support for the non-covalent immobilization of an l-phenylalanine derived chiral diamine organocatalyst for asymmetric aldol reactions. The immobilization is established by an acid–base interaction between the sulphonic acid group and the amine function. The acidity and in particular the electronic withdrawing environment of the sulphonic acid groups influence enormously the catalytic performance of the non-covalent immobilized chiral diamine catalyst (aromatic > aliphatic).

Environmentally benign catalyst: Synthesis, characterization, and properties of pyridinium dicationic molten salts (ionic liquids) and use of application in esterification

A series of pyridinium based dicationic [C6(Mpy)2], [C10(Epy)2], [C10(Bpy)2] with traditional counter anions such as Br−, BF4−, PF6− and Tf2N− molten salts (ionic liquids (ILs)) were synthesized. Most of them can be classified as ionic liquids (mp<100°C). Key physicochemical properties, such as melting point, thermal stability and solubility in common solvents were determined. The synthesized dicationic salt 1,1′-hexane-1,6-diylbis (3-methylpyridinium) dibromide tested for the esterification of carboxylic acid derivatives with a variety of alkyl halides in the presence of triethylamine. The esterification was carried out under mild reaction conditions and without any additional organic solvent. The results showed that carboxylic acids were successfully converted into esters with good yields and high selectivity. The produced esters were easily recovered due to immiscibility with the ionic liquid as green reaction medium. The ionic liquid was recycled and reused. Thus, reported dicationic ionic liquid was a promising catalyst for esterification reaction.

Preparation of fibrous sulfated zirconia (SO 42−/ZrO 2) solid acid catalyst using collagen fiber as the template and its application in esterification

A novel fibrous sulfated ZrO 2 (SO 4 2−/ZrO 2) solid acid catalyst was prepared using collagen fiber as the template. The surface morphology of the as-prepared catalyst was observed by scanning electron microscopy (SEM), and the corresponding crystalline properties were determined by X-ray diffraction (XRD). To collect the structural properties of the SO 4 2−/ZrO 2 catalyst, N 2 adsorption/desorption method was carried out. Temperature-programmed decomposition (TPD) of ammonia was conducted to determine the acid strength of the catalyst. It was found that the SO 4 2−/ZrO 2 catalyst had well-defined fibrous morphology and porous structure, which contained both medium strong acidic sites and strong acidic sites. Subsequently, the esterification of acetic acid with n-butanol was carried out to evaluate the catalytic activity and reusability of the SO 4 2−/ZrO 2 catalyst. The SO 4 2−/ZrO 2 catalyst exhibited high catalytic activity as compared with other solid acid catalysts. Furthermore, the catalyst can be reused 6 times without significant loss of catalytic activity, suggesting a satisfied reusability.

Production and use of lipases in bioenergy: a review from the feedstocks to biodiesel production.

Lipases represent one of the most reported groups of enzymes for the production of biofuels. They are used for the processing of glycerides and fatty acids for biodiesel (fatty acid alkyl esters) production. This paper presents the main topics of the enzyme-based production of biodiesel, from the feedstocks to the production of enzymes and their application in esterification and transesterification reactions. Growing technologies, such as the use of whole cells as catalysts, are addressed, and as concluding remarks, the advantages, concerns, and future prospects of enzymatic biodiesel are presented.

Synthesis, Characterization of Novel Hexamethyleneiminium-Based Ionic Liquids and their Application in Esterification

Three novel Brønsted acidic ionic liquids (ILs), 1-(3-sulfopropyl) hexamethyleneiminium hydrogen sulfate ([HMIPS]HSO4), 1-(3-sulfopropyl) hexamethyleneiminium tosilate ([HMIPS]OTs) and 1-hexamethyleneiminium hydrogen sulfate([HMI]HSO4), were synthesized and characterized by1H NMR, FT-IR and DSC-TG. Their catalytic activities for the esterification of citric acid with n-butanol were examined and compared with the imidazolium-based ILs. The results showed that the hexamethyleneiminium-based ILs exhibits excellent catalytic activity. By using [HMIPS]HSO4as the catalyst, the yield of tributyl citrate reached 97.5%. Furthermore, the catalysts were reused at least 10 times without significant decrease in activity

Preparation of nano-SO 4 2− /TiO2 catalyst and its application in esterification of sebacic acid with 2-ethyl hexanol

A pure anatase phase nano-SO 4 2− /TiO2 catalysts were synthesized and their catalytic activities were tested. Nano-SO 4 2− /TiO2 shows high activity and effective re-usable when used as basic catalysts for the synthesis of dioctyl sebacate.

Alkyl Sulfonate Functionalized Ionic Liquids: Synthesis, Properties, and Their Application in Esterification

Ionic liquids based on alkyl sulfate anions and alkyl sulfonate functionalized cations were prepared from commercially available and cheap materials and their thermal-instability properties were studied in detail. These ionic liquids were active catalysts for esterification and they gave moderate to high yields. The catalytic performance was found to be much better than that of conventional non-cation functionalized ionic liquids and close to sulfonic acid functionalized ionic liquids. The catalytic process in this reaction was investigated by electrospray ionization mass spectrometry and a plausible reaction mechanism is suggested. ：采用廉价易得的原料合成了阳离子含有烷基磺酸酯官能团的功能化离子液体, 并考察了其热稳定性. 该离子液体可催化羧酸的酯化反应, 其催化活性高于阳离子非功能化的离子液体, 而与磺酸功能化离子液体相当. 同时采用电喷雾电离质谱考察了该离子液体在酯化反应中的作用. We investigated methyl sulfonate-functionalized ionic liquids and found that they are excellent catalysts for esterification. The sulfonic acid group formed by the hydrolysis of methyl sulfonate is proposed to be the most important catalytic center.

Synthesis of sulfated titania supported on mesoporous silica using direct impregnation and its application in esterification of acetic acid and n-butanol

XRD profiles of the composites of S-TiO 2/MCM-41 with different TiO 2 contents. The low angle peaks indicate the MCM-41-like structure retained and a TiO 2 phase appeared at high angle region. [Display omitted]

The Synthesis of Polymeric Catalyst Using Ion Exchange Resin and Its Application for Esterification

Abstract The copolymer complexes have been synthesized from cation and/or anion resin with metal catalyst such as aluminum chloride or iron(III) chloride. Electron microprobe X-ray analysis demonstrated that aluminum and iron were distributed uniformly in the copolymer complex. The catalytic activity for esterification of dibasic organic acids was discussed and showed that copolymer complex from porous type cation exchange resin was much better catalyst than that from gel type.