Adi Wolfson

Palladium-catalyzed heck and suzuki coupling in glycerol

The Heck coupling of halobenzenes with various alkenes and the Suzuki cross coupling of halobenzenes with phenylboronic acid were successfully performed in glycerol as the reaction solvent using homogeneous and heterogeneous palladium catalysts. Glycerol is a renewable and recyclable green solvent that is able to dissolve organic substrates, inorganic bases, and palladium complexes, and that allows easy isolation of the reaction product by simple extraction with glycerol-immiscible solvents such as diethyl ether, hexane, and dichloromethane.

Efficient synthetic protocols in glycerol under heterogeneous catalysis.

The massive increase in glycerol production from the transesterification of vegetable oils has stimulated a large effort to find novel uses for this compound. Hence, the use of glycerol as a solvent for organic synthesis has drawn particular interest. Drawbacks of this green and renewable solvent are a low solubility of highly hydrophobic molecules and a high viscosity, which often requires the use of a fluidifying co-solvent. These limitations can be easily overcome by performing reactions under high-intensity ultrasound and microwaves in a stand-alone or combined manner. These non-conventional techniques facilitate and widen the use of glycerol as a solvent in organic synthesis. Glycerol allows excellent acoustic cavitation even at high temperatures (70-100 °C), which is otherwise negligible in water. Herein, we describe three different types of applications: 1) the catalytic transfer hydrogenation of benzaldehyde to benzyl alcohol in which glycerol plays the dual role of the solvent and hydrogen donor; 2) the palladium-catalyzed Suzuki cross-coupling; and (3) the Barbier reaction. In all cases glycerol proved to be a greener, less expensive, and safer alternative to the classic volatile organic solvents.

Glycerol triacetate as solvent and acyl donor in the production of isoamyl acetate with Candida antarctica lipase B

Glycerol triacetate was successfully used as a green solvent and as the acyl donor in the transesterification of isoamyl alcohol to produce isoamyl acetate using free and immobilized Candida antarctica lipase B. Immobilized lipase was more catalytically active than free lipase and could be easily separated from the reaction mixture by filtration. In addition, it was found that increasing either the reaction temperature or the enzyme to substrate ratio increased the conversion of isoamyl alcohol. Using triacetin as the solvent also enabled the separation of product by simple extraction with petroleum ether and catalyst recycling.

Transfer hydrogenations of benzaldehyde using glycerol as solvent and hydrogen source

Benzaldehyde was successfully reduced by catalytic transfer hydrogenation in glycerol using several ruthenium based complexes and bases. Glycerol was employed as a green solvent and hydrogen source...

Glycerol derivatives as green reaction mediums

Abstract Representative glycerol derivatives were employed as green solvents for selected organic transformations. In all reactions it was found that both reaction performance and product extraction yields were affected by solvent type and polarity. The solubility of the substrates in the solvent was the key step in product yield determination, while the product solubility in the reaction solvent determined the effectiveness of its extraction.

Transfer Hydrogenations of Nitrobenzene Using Glycerol as Solvent and Hydrogen Donor

Abstract Aniline has been successfully produced by catalytic transfer hydrogenation of nitrobenzene in glycerol, which was employed as both a green solvent and a hydrogen donor. As a solvent, glycerol also facilitated easy separation of the product and recycling of the catalyst.

Green synthesis of isoamyl acetate in glycerol triacetate

Abstract Glycerol triacetate was successfully used as a green solvent and as the acyl donor in the production of isoamyl acetate by the transesterification of isoamyl alcohol over an acidic ion-exchange resin. Using glycerol triacetate as the solvent also enabled simple product recovery, easy catalyst separation and recycling, and microwave-promoted heating.

A novel system consisting of Rh-DuPHOS and ionic liquid for asymmetric hydrogenations.

The ionic liquid [bmim][PF6] was found to provide extra stability to the air-sensitive chiral catalyst Rh-MeDuPHOS in asymmetric hydrogenation of enamides.

CleanServs: clean services for a more sustainable world:

Purpose – The paper aims to describe a novel framework for service design to achieve the overall goal of sustainability and to characterize it while exploring the benefit of doing so for both sustainability and service. This novel framework also proposes new opportunities for sustainability-oriented innovation. Design/methodology/approach – The paper presents a novel approach to design and implement services that will lead to a reduction in the production of goods and will offer alternatives that will reduce whatever production process is involved in its creation, i.e. clean service – CleanServ. Findings – The authors’ findings suggest that a CleanServ is a service that is competitive with, if not superior to, its conventional tangible or intangible counterparts and one that reduces the use of natural resources and cuts or eliminates emissions and wastes. CleanServs can be categorized into five different groups based on their fundamental contribution to sustainability: prevention, reduction, replacement, ...

Heterogenization of Rh-MeDuPHOS by occlusion in polyvinyl alcohol films

A new recyclable chiral heterogeneous catalytic system was obtained by the occlusion of Rh-MeDuPHOS in polyvinyl alcohol film. Enantiomeric excess of up to 96% was achieved in the asymmetric hydrogenation of methyl 2-acetamidoacrylate in aqueous medium.