In view of the diminishing oil resources and the ongoing climate change, the use of efficient and environmentally benign technologies for the utilization of renewable resources has become indispensible. Therein, hydrogenolysis reactions offer a promising possibility for future biorefinery concepts. These reactions result in the cleavage of C-C and C-O bonds by hydrogen and allow direct access to valuable platform chemicals already integrated in today's value chains. Thus, hydrogenolysis bears the potential to bridge currently available technologies and future biomass-based refinery concepts. This Review highlights past and present developments in this field, with special emphasis on the direct utilization of cellulosic feedstocks.

Hydrogenolysis Goes Bio: From Carbohydrates and Sugar Alcohols to Platform Chemicals

Angesichts begrenzter Reserven fossiler Rohstoffe und einem Voranschreiten des Klimawandels werden effiziente und umweltfreundliche Technologien zur Nutzbarmachung erneuerbarer Rohstoffe unerlasslich. Dabei stellt die Hydrogenolyse eine vielversprechende Reaktion fur zukunftige Bioraffineriekonzepte dar. Sie resultiert in einer C-C- und C-O-Bindungsspaltung mit Wasserstoff und erlaubt einen direkten Zugang zu nutzlichen Plattformchemikalien, die bereits heute Teil der Wertschopfungsketten der chemischen Industrie sind. Aus diesem Grund birgt die Hydrogenolyse das Potential, existierende Wertschopfungsketten und zukunftige Bioraffineriekonzepte zu verbinden. Dieser Aufsatz stellt vorausgegangene und aktuelle Entwicklungen in diesem Bereich mit besonderem Augenmerk auf der direkten Umsetzung von Cellulose als Rohstoffe dar.

Hydrogenolyse goes Bio: Von Kohlenhydraten und Zuckeralkoholen zu Plattformchemikalien

The depolymerization of cellulose is carried out in the ionic liquid 1-butyl-3-methylimidazolium chloride in the presence of hydrogen gas. First, the ketal 1,1-diethoxycyclohexane and cellobiose were used as model substrates. For the depolymerization of cellulose itself, the combination of a heterogeneous metal catalyst and a homogeneous ruthenium catalyst proved effective. One of the possible roles of the ruthenium compound is to enhance the transfer of hydrogen to the metallic surface. The cellulose is fully converted under relatively mild conditions, with sorbitol as the dominant product in 51–74 % yield.

Reductive Splitting of Cellulose in the Ionic Liquid 1-Butyl-3-Methylimidazolium Chloride

A process for the production of a lower polyhydric alcohol or a mixture thereof by the hydrogenation and hydrolysis of a carbohydrate. The first stage hydrogenation produces higher polyhydric alcohols, such as sorbitol. In the second stage these higher polyhydric alcohols are selectively converted under the appropriate reaction conditions to lower polyhydric alcohols, such as ethylene glycol and 1,2-propylene glycol, using a sulfide-modified ruthenium catalyst.

Two stage hydrogenolysis of carbohydrate to glycols using sulfide modified ruthenium catalyst in second stage

A process for the separation of mannose is disclosed which comprises the selective adsorption of same on certain types of zeolitic molecular sieves. The process is especially useful for separating mannose from glucose epimerization product or plant tissue hydrolyzate, using zeolites selected from the group consisting of BaX, BaY, SrY, NaY and CaY.

Separation of mannose by selective adsorption on zeolitic molecular sieves

Homogeneous catalytic hydrogenation of sugars

Regeneration of supported ruthenium catalysts. A supported ruthenium catalyst which has been used for conversion of carbohydrates to polyhydric alcohols is regenerated by contacting the catalyst with an aqueous solution of a mineral acid, such as sulfuric, hydrochloric, or phosphoric acid. Dilute acids, e.g., 0.01 N to 0.5 N, are preferred.

Regeneration of supported ruthenium catalyst

A high yield process for the polyalkylation of hexitols and hexitol inner ethers is presented wherein aqueous dispersions of monoalkali metal alkoxides thereof in organic solvent are reacted with alkyl monohalides to first form the monoalkylated hexitols or hexitol inner ether and thereafter further alkylated by addition of reactants to form the completely alkylated derivative.

Etherification process for hexitols and anhydrohexitols

A homogeneous hydrogenation process is disclosed. The process, which is useful in the preparation of hydrogenated derivatives of compounds selected from the group consisting of monosaccharides, disaccharides, trisaccharides, polysaccharides, corn starch hydrolyzate, and compounds represented by the formula RH 2 C--CO--CH 2 R wherein R is hydroxyl or halogen, comprises contacting a solution of one of these compounds with hydrogen in the presence of a catalyst comprising a ruthenium triphenyl phosphine complex and a strong acid.

Homogeneous hydrogenation of saccharides using ruthenium triphenyl phosphine complex

A homogeneous hydrogenation process is disclosed. The process, which is useful in the preparation of hydrogenated derivatives of compounds having one of the following formulas ##STR1## wherein R is --Cl, --Br, --F, or --OH, comprises contacting a solution of one of these compounds with hydrogen in the presence of a catalyst comprising a ruthenium triphenyl phosphine complex and a strong acid.

Walter M. Kruse

Papers

Homogeneous catalytic hydrogenation of sugars

Regeneration of supported ruthenium catalyst

Etherification process for hexitols and anhydrohexitols

Homogeneous hydrogenation of saccharides using ruthenium triphenyl phosphine complex

Homogeneous hydrogenation process