Oxidation of Furfural and Furan Derivatives to Maleic Acid in the Presence of a Simple Catalyst System Based on Acetic Acid and TS-1 and Hydrogen Peroxide.

Titanium silicate molecular sieve (TS-1) and acetic acid efficiently catalyze the oxidation of furan and furan derivatives to the corresponding maleic acid (MA) in very good yields using hydrogen peroxide as an oxidizing agent. The effect of various solvents, the effect of temperature, reaction time, concentration of hydrogen peroxide, and quantities of the catalyst on the MA yield was studied. With the best conditions, MA is the sole product obtained after a fast and simple purification by filtration and evaporation.

Mechanocatalytic Depolymerization of Cellulose With Perfluorinated Sulfonic Acid Ionomers.

Here, we investigated that the mechanocatalytic depolymerization of cellulose in the presence of Aquivion, a sulfonated perfluorinated ionomer. Under optimized conditions, yields of water soluble sugars of 90-97% were obtained using Aquivion PW98 and PW66, respectively, as a solid acid catalyst. The detailed characterization of the water soluble fraction revealed (i) the selective formation of oligosaccharides with a DP up to 11 and (ii) that depolymerization and reversion reactions concomitantly occurred during the mechanocatalytic process, although the first largely predominated.

Transglycosylation: A Key Reaction to Access Alkylpolyglycosides from Lignocellulosic Biomass.

An overview is provided on the recent advances in transglycosylation of cellulose and hemicellulose with either short-chain or long-chain alkyl alcohols. Catalytic processes are compared in terms of yield, selectivity and space-time yield, with a view to identifying the most promising pathways for future developments. In this context, the synthesis of alkylpolyglycosides directly from lignocellulosic biomass is discussed while keeping in mind the impact of the botanical origin on the transglycosylation reaction and the product distribution.

Carnitine alkyl ester bromides as novel biosourced ionic liquids, cationic hydrotropes and surfactants.

Hypothesis: In contrast to anionic and nonionic amphiphilic substances, bio-based cationic ones are very rare. Cationic amphiphiles are mostly based on quaternary ammonium, pyridinium or imidazolium groups that are either badly biodegradable or have toxic residues even after degradation. In the search for green alternatives to cationic hydrotropes and amphiphiles, natural l-carnitine could be a promising candidate for a cationic headgroup.

Conversion of Cellulose into Amphiphilic Alkyl Glycosides Catalyzed by Aquivion, a Perfluorosulfonic Acid Polymer.

The perfluorosulfonic acid (PFSA) Aquivion PW98 is an amphiphilic solid superacid which is shown to catalyze the conversion of cellulose into amphiphilic alkyl glycosides (AAGs) in 85 % yield (with 97 % selectivity). The process involves a mechanocatalytic depolymerization of cellulose followed by a direct glycosylation with n-dodecanol. In comparison to H SO and solid acid catalysts commonly employed in cellulose processing, Aquivion PFSA PW98 is not only recyclable but also exhibits superior catalytic performances in terms of yield, selectivity, and reactor productivity.

Acid-Assisted Ball Milling of Cellulose as an Efficient Pretreatment Process for the Production of Butyl Glycosides.

Ball milling of cellulose in the presence of a catalytic amount of H2SO4 was found to be a promising pre-treatment process to produce butyl glycosides in high yields. Conversely to the case of water, n-butanol has only a slight effect on the recrystallization of ball-milled cellulose. As a result, thorough depolymerization of cellulose prior the glycosylation step is no longer required, which is a pivotal aspect with respect to energy consumption.

Acidic pretreatment of wheat straw in decanol for the production of surfactant, lignin and glucose.

Wheat straw is an abundant residue of agriculture which is increasingly being considered as feedstock for the production of fuels, energy and chemicals. The acidic decanol-based pre-treatment of wheat straw has been investigated in this work. Wheat straw hemicellulose has been efficiently converted during a single step operation into decyl pentoside surfactants and the remaining material has been preserved keeping all its promises as potential feedstock for fuels or value added platform chemicals such as hydroxymethylfurfural (HMF).

Photochemical electron transfer mediated addition of naphthylamine derivatives to electron-deficient alkenes.

Using photochemical electron transfer, N,N-dimethylnaphthylamine derivatives are added to α,β-unsaturated carboxylates. The addition takes place exclusively in the α-position of electron-deficient alkenes and mainly in the 4-position of N,N-dimethylnaphthalen-1-amine. A minor regioisomer results from the addition in the 5-position of this naphthylamine.

Direct conversion of xylan into alkyl pentosides.

Xylan has been used as a raw material in the synthesis of butyl, octyl and decyl glycosides. Mixtures of D-xylose-, L-arabinose- and D-glucose-based surfactants were obtained under smooth conditions with high yields in a one-pot process. The surface activities of octyl and decyl glycosides thus obtained have been studied and compared with that of pure alkyl D-xylosides.

Low catalyst loadings for the production of carboxylic acids from polysaccharides and hydrogen peroxide.

The oxidation of starch, xylans, potato flesh and wheat flour by H(2)O(2), in the presence of MSO(4) (M=Cu, Fe) as catalyst, led to depolymerization, and formation of solutions containing polyhydroxycarboxylic acids. Some of these oxidized compounds facilitate the process, leading to efficient transformations even with very low amounts of catalyst.

Straightforward synthesis of enantiopure (R)- and (S)-trifluoroalaninol.

Two efficient routes are reported for the synthesis of both enantiomers of trifluoroalaninol in enantiopure form. The first pathway involves a Strecker-type reaction performed from a chiral trifluoromethyloxazolidine (Fox). The second route, which is more direct, involves, as a key step, the reduction of chiral oxazolidines or imines derived from ethyl trifluoropyruvate.

Straightforward synthesis of (S)- and (R)-alpha-trifluoromethyl proline from chiral oxazolidines derived from ethyl trifluoropyruvate.

[Structure: see text] A concise synthesis of both enantiomers of alpha-Tfm-proline and (S)-alpha-Tfm-prolinol from ethyl trifluoropyruvate is reported. The key step is a diastereoselective allylation reaction of ethyl trifluoropyruvate and (R)-phenylglycinol-based oxazolidines or imine. The lactone obtained by cyclization of the resulting hydroxy ester proved to be a valuable intermediate for the synthesis of (S)-alpha-Tfm-allylglycine and (S)-alpha-Tfm-norvaline in enantiopure form.

Thiocarbonyl compounds as regulating reagent in the radical addition of tertiary amines with alkenes using photoelectron transfer conditions.

The efficiency of the photoinduced radical addition of tertiary amines to olefinic double bonds is significantly enhanced and the stereoselectivity is influenced when thiocarbonyl compounds are added to the reaction mixture.

Origin of chiral induction in radical reactions with the diastereoisomers (5R)- and (5S)-5-l-menthyloxyfuran-2[5H]-one.

Acetalization of 5-hydroxyfuran-2[5H]-one with l-menthol yields (5R)- (1) and (5S)-5-l-menthyloxyfuran-2[5H]-one (2) in equal amounts. The diastereomer 1 crystallizes preferentially. For the first time, the isolation of pure diastereoisomer 2 is reported.