High Catalytic Performance of Aquivion PFSA, a Reusable Solid Perfluorosulfonic Acid Polymer, in the Biphasic Glycosylation of Glucose with Fatty Alcohols

Superacid Resin-Based Heterogeneous Catalysts for the Selective Acylation of 1,2-Methylenedioxybenzene

In this work, we firstly report on the use of highly active and selective Aquivion superacid resins as heterogeneous catalysts for the acylation of 1,2-methylenedioxybenzene (MDB) with propionic anhydride (AP). The reaction was investigated and optimized using solvent-free conditions to selectively produce 3,4-methylenedioxypropiophenone (MDP1P), a key intermediate for the manufacture of active ingredients used in insecticide formulations with a volume of production of roughly 3000 t/y. Interestingly, Aquivion-based catalysts allows to work in mild reaction conditions (i. e. 80 °C), obtaining MDP1P yields as high as 44 % after only 1 h of reaction (selectivity 83 %). A detailed study of the AP reactivity demonstrated its tendency to promote oligomerization reactions that, as confirmed by ex-situ and in-situ FT-ATR analyses, caused the deactivation of the catalyst forming surficial carbonaceous residues. In this context, a fast oxidation of the resin surface organic residues using a diluted HNO3 (or H2 O2 ) solution was proven to be an efficient method to regenerate the catalyst, which can be reused for several reaction cycles. The results obtained in preliminary scale-up tests were basically unaffected by the reaction volume (up to 800 mL), paving the way for possible future applications of the process.

Chemical synthesis of amphiphilic glycoconjugates: Access to amino, fluorinated and sulfhydryl oleyl glucosides

Amphiphilic glycoconjugates offer an important prospect for development as chemical biology tools and biosurfactants. The chemical synthesis of such materials is required to expedite such prospect, compounded by the example of oleyl glycosides. Herein, we report a mild and reliable glycosylation method to access oleyl glucosides, glycosidating oleyl alcohol with α-trichloroacetimidate donors. We demonstrate capability for this methodology, extending it to synthesise the first examples of pyranose-component fluorination and sulfhydryl modifications within glucosides and glucosamines of oleyl alcohol. These compounds provide an exciting series of tools to explore processes and materials that utilise oleyl glycosides, including as probes for glycosphingolipid metabolism.

Surface Properties of Alkyldi(oxyethylene) β-D-Maltoside

A series of nonionic disaccharide-based surfactants alkyldi(oxyethylene) β-d-maltosides (4a-4h, n = 6-16) were synthesized, and their physicochemical properties were further investigated. Six β-D-maltosides (4c-4h, n = 8-16) exhibited a fan-shaped texture feature, whereas hexyldi(oxyethylene) β-D-maltoside (4a) had the strongest hygroscopicity. Owing to the incorporation of the hydrophilic dioxyethyl spacer (-(OCH₂CH₂)₂-), the related water solubility improved significantly. Tetradecyldi(oxyethylene) β-D-maltoside (4g) had good water solubility, whereas hexadecyldi(oxyethylene) β-D-maltoside (4h) had weak water solubility. Meanwhile, the surface tension of β-D-maltosides (4a-4g, n = 6-14) had a decreasing tendency with increasing the alkyl chain length, whereas 4g had the best surface activity. Furthermore, decyldi(oxyethylene) β-D-maltoside (4e) had the best foaming ability and foam stability. Dodecyldi(oxyethylene) β-D-maltoside (4f) had the best emulsifying property in the rapeseed oil/water system. In contrast, both ammonium dodecyl sulfate (NH₄DS)/4f and cetyltrimethylammonium chloride (CTAC)/4f binary surfactant systems showed a synergistic effect in surface activity because the C_CMC/CMC^id_mix was <1. NaCl impacted the surface activity of the aqueous 4f solution through salt-surfactant synergistic effects. The results showed that such surfactants should have potential applications in the related field in the future.

Non-Porous Sulfonic Acid Catalysts Derived from Vacuum Residue Asphaltenes for Glycerol Valorization via Ketalization with Acetone

In this study, an approach for the preparation of heterogeneous acid catalysts based on asphaltenes isolated from vacuum residue is proposed. Varying the conditions for the sulfonation of asphaltenes made it possible to obtain materials with an acid value of 1.16 to 2.76 meq g−1 and a total sulfur content of 6.4 to 12.3 wt%. The samples obtained were characterized by acid-base titration, nitrogen adsorption, sulfur elemental analysis and transmission electron microscopy techniques, and were studied as potential acid catalysts in the ketalization reaction between glycerol and acetone. Sulfonated asphaltenes (SA) were characterized by a homogeneous distribution of sulfonic groups over the granule surface and an almost complete absence of a porous structure. The ketalization reaction in the presence of SA proceeded without intradiffusion restrictions; as a result of which, their activity was higher than for known heterogeneous catalysts. The most active SA sample (total acid value, 1.16 meq g−1) had an apparent activation energy of 18.0 kJ mol−1, which was lower than the value obtained for the zeolite BEA-40 (29–53 kJ mol−1) and the Amberlyst 36 resin (27 kJ mol−1), and was close to the value for the homogeneous p-TSA catalyst (14.5 kJ mol−1). The SA heterogeneous catalysts did not show any acid leaching and had no loss of activity after five catalytic cycles, with the total turnover number TON = 7247.

Surfactant-mediated thioglycosylation of 1-hydroxy sugars in water

Thioglycosides are an important class of sugars, since they can be used as non-ionic biosurfactants, biomimetic glycosides, and building blocks for carbohydrate synthesis. Previously, Brønsted- or Lewis-acid-catalyzed dehydrative glycosylations between a 1-hydroxy sugar and a thiol have been reported to yield open-chain dithioacetal sugars as the major products instead of the desired thioglycosides. These dithioacetal sugars are by-products derived from the endocyclic bond cleavage of the thioglycosides. Herein, we report dehydrative glycosylation in water mediated by a Brønsted acid-surfactant combined catalyst (BASC). Glycosylations between 1-hydroxy furanosyl/pyranosyl sugars and primary, secondary, and tertiary aliphatic/aromatic thiols in the presence of dodecyl benzenesulfonic acid (DBSA) provided the thioglycoside products in moderate to good yields. Microwave irradiation led to improvements in the yields and a shortening of the reaction time. Remarkably, open-chain dithioacetal sugars were not detected in the DBSA-mediated glycosylations in water. This method is a simple, convenient, and rapid approach to produce a library of thioglycosides without the requirement of anhydrous conditions. Moreover, this work also provides an excellent example of complementary reactivity profiles of glycosylation in organic solvents and water.

Efficient conversion of d-mannitol into 1,2:5,6-diacetonide with Aquivion-H as a recyclable catalyst

Heterogeneous solid catalysis by the commercially available perfluorosulfonic ionomer Aquivion-H allowed 1,2:5,6-diacetonide of d-mannitol (1), immediate precursor of important unichiral C3-synthons, to be efficiently obtained from d-mannitol and 2,2-dimethoxypropane in DMF at room temperature. The 1,2-monoacetonide, whose intermediate formation is the rate-limiting step, could be almost completely converted into 1 with limited concurrent transformation of 1 into triacetonides. In line with recent literature reports, these results indicate that heterogeneous catalysis by Aquivion-H surpasses the performances of homogeneous acidic catalysis assuring, presumably for its peculiar morphology, a higher product selectivity. Easy recovery at the end of the reaction and recyclability are additional advantages of this solid acid catalyst.

Synthesis and property of alkyl dioxyethyl α-D-xyloside

Due to the inherent defects of the long alkyl chain in the related hydrophilicity and water solubility, alkyl α-D-xylosides (7) had hardly the practical application as sugar-based surfactants and should be reconstructed to obtain alkyl dioxyethyl α-D-xylosides (5) with dioxyethylene fragment (-(OCH2CH2)2-)) as the hydrophilic spacer to increase the related TPSA value. With D-xylose as the raw material, 1,2-cis alkyl dioxyethyl α-D-xylosides (5a-5f, n = 6-12) were stereoselectively synthesized. Their physicochemical properties including water solubility, surface tension, foamability, emulsification, thermotropic liquid crystal, and hygroscopicity had been investigated. Their water solubility was found to decrease gradually whereas their calculated HLB numbers were 14.72 → 11.67 (n = 6 → 12) with increasing alkyl chain length (n). Dodecyl dioxyethyl α-D-xyloside (5f) had not water solubility because the HLB number was low. Furthermore, their CMC values decreased with increasing the alkyl chain length, and the CMC value of decyl dioxyethyl α-D-xyloside (5e) was as low as 9.21 × 10-5 mol·L-1. Octyl dioxyethyl α-D-xyloside (5c) had the lowest surface tension (27.25 mN·m-1) at the CMC. Both of nonyl and decyl dioxyethyl α-D-xylosides (5d & 5e) possessed good foaming power and foam stability. Decyl dioxyethyl α-D-xyloside (5e) had the strongest emulsifying property either in the toluene/water system or in the octane/water system. Nonyl dioxyethyl α-D-xylosides (5d) had the most stylish SA texture. Hexyl dioxyethyl α-D-xyloside (5a) possessed the strongest hygroscopicity. Therefore, the alkyl dioxyethyl α-D-xylosides as a class of novel sugar-based surfactants will be widely considered as promising candidates for various practical applications.

Water Solubility and Surface Property of Alkyl Di-/Tri-/Tetraoxyethyl β-d-Xylopyranosides

Alkyl di-/tri-/tetraoxyethyl β-d-xylopyranosides as derivatives of alkyl xylosides are a class of non-ionic sugar-based surfactants. They were stereoselectively synthesized by the Helferich method. Their properties including hydrophilic-lipophilic balance number, water solubility, surface property, foam property, emulsifying property, and thermotropic liquid crystal property were mainly investigated. The results showed that their water solubility decreased with increasing the alkyl chain length and increasing the number of the oligooxyethyl fragment. The critical micelle concentration had a monotonous decreasing trend with increasing the alkyl chain length. Nonyl di-/tri-/tetraoxyethyl β-d-xylopyranosides [-(OCH₂CH₂)_m-, where m = 2, 3, and 4] exhibited the most excellent foaming ability and foam stability. In the n-octane/water system, dodecyl tetraoxyethyl β-d-xylopyranosides and tetradecyl tetraoxyethyl β-d-xylopyranosides had the strongest emulsion ability. In addition, some alkyl di-/tri-/tetraoxyethyl β-d-xylopyranosides had thermotropic liquid crystal properties. Such sugar-based surfactants, alkyl di-/tri-/tetraoxyethyl β-d-xylopyranosides, will be expected to develop for a variety of practical application.

Esterification of Glycerol With Oleic Acid Over Hydrophobic Zirconia-Silica Acid Catalyst and Commercial Acid Catalyst: Optimization and Influence of Catalyst Acidity

Catalytic esterification of glycerol with oleic acid (OA) was optimized over hydrophobic mesoporous zirconia-silica heterogeneous acid catalyst (ZrO₂-SiO₂-Me&Et-PhSO₃H) and benchmarked with commercial catalysts (Aquivion and Amberlyst 15) in order to examine the effect of catalyst acidity on conversion, yield and product selectivity. The process optimisation results showed an 80% conversion with a 59.4% glycerol mono-oleate (GMO) and 34.6% glycerol dioleate (GDO) selectivities corresponding to a combined GMO and GDO selectivity of 94.8% at equimolar OA-to-glycerol ratio, 160°C reaction temperature, 5 wt% catalyst concentration with respect to the OA weight and 4 h reaction time. This work reveals that the hydrophobic and mild acidic ZrO₂-SiO₂-Me&Et-PhSO₃H catalyst outperformed Amberlyst 15 and Aquivion with a yield of 82% and GMO selectivity of 60%. It is found that catalyst acidity is a key parameter for catalytic activity and conversion rate. Nevertheless, high acidity/acid strength reduced the product yield in the glycerol esterification of OA.

Renewable lubricants with tailored molecular architecture

We present a strategy to synthesize three types of renewable lubricant base oils with up to 90% yield using 2-alkylfurans, derived from nonfood biomass, and aldehydes, produced from natural oils or biomass through three chemistries: hydroxyalkylation/alkylation (HAA), HAA followed by hydrogenation, and HAA followed by hydrodeoxygenation. These molecules consist of (i) furan rings, (ii) saturated furan rings, and (iii) deoxygenated branched alkanes. The structures of these molecules can be tailored in terms of carbon number, branching length, distance between branches, and functional groups. The site-specific, energy-efficient C-C coupling chemistry in oxygenated biomass compounds, unmatched in current refineries, provides tailored structure and tunable properties. Molecular simulation demonstrates the ability to predict properties in agreement with experiments, proving the potential for molecular design.

Impact of shaping Aquivion PFSA on its catalytic performances

The shaping of Aquivion PFSA into micropellets is a good compromise between its catalytic performances, its ease of recovery at the end of the reaction and its deactivation rate.

AQUIVION® perfluorosulfonic acid resin for butyl levulinate production from furfuryl alcohol

Multivariate analysis allowed the optimization of a reaction catalyzed by a robust solid acid Aquivion® P87S.

Aquivion-Carbon Composites with Tunable Amphiphilicity for Pickering Interfacial Catalysis

A key demand in biomass conversion is how to achieve high reactivity with immiscible reagents with the use of neither cosolvents nor additives. Pickering interfacial catalysis encompassing the design of amphiphilic catalysts behaving concomitantly as emulsifiers offers an elegant solution. In this study, we prepared a systematic series of amphiphilic Aquivion-carbon composites by the hydrothermal carbonization of guar gum with Aquivion perfluorosulfonic superacid. By tuning the Aquivion-carbon composition, materials with tunable hydrophilic-lipophilic properties could be prepared, showing high versatility for conducting biphasic reactions without stirring. In particular, an optimal formulation based on 5:1 Aquivion-carbon could be developed, showing high activity in the transesterification reaction of glyceryl trioleate with methanol at 100 °C with good reusability due to the genesis of stable Pickering emulsions.

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. A section dedicated to the physicochemical properties and ecological footprint of alkylpolyglycosides is also included.

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 H₂ SO₄ 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.