The dehydration membrane reactor for methanol production from CO.sub.2 hydrogenation includes one or more porous supports, a dehydration membrane on the one or more porous supports, and a catalyst layer on the dehydration membrane. The one or more porous supports include hollow ceramic fibers and the dehydration membrane includes NaA zeolite. The reactor is made by dip-coating the porous supports in a zeolite crystal seed solution and drying the coated porous support. The coated porous support is dried at about 80° C. and then heated to a temperature above about 200° C. The NaA zeolite membrane is then grown on the seeded support, and a catalyst layer is applied to the zeolite membrane. A feedstream including carbon dioxide and hydrogen is fed to the catalyst layer, where a product stream including methanol and water is evolved. The water is then removed from the product stream through the dehydration membrane to produce a high-purity methanol product.

Provided is a method for preparing a diol. In the method, a saccharide and hydrogen as raw materials are contacted with a catalyst in water to prepare the diol. The employed catalyst is a composite catalyst comprised of a main catalyst and a cocatalyst, wherein the main catalyst is a water-insoluble acid-resistant alloy; and the cocatalyst is a soluble tungstate and/or soluble tungsten compound. The method uses an acid-resistant, inexpensive and stable alloy needless of a support as a main catalyst, and can guarantee a high yield of the diol in the case where the production cost is relatively low.

Provided is a method for preparing a diol. In the method, a saccharide and hydrogen as raw materials are contacted with a catalyst in water to prepare the diol. The employed catalyst is a composite catalyst comprised of a main catalyst and a cocatalyst, wherein the main catalyst is a water-insoluble acid-resistant alloy; and the cocatalyst is a soluble tungstate and/or soluble tungsten compound. The method uses an acid-resistant, inexpensive and stable alloy needless of a support as a main catalyst, and can guarantee a high yield of the diol in the case where the production cost is relatively low.

Provided is a method for preparing a diol. In the method, a saccharide and hydrogen as raw materials are contacted with a catalyst in water to prepare the diol. The employed catalyst is a composite catalyst comprised of a main catalyst and a cocatalyst, wherein the main catalyst is a water-insoluble acid-resistant alloy; and the cocatalyst is a soluble tungstate and/or soluble tungsten compound. The method uses an acid-resistant, inexpensive and stable alloy needless of a support as a main catalyst, and can guarantee a high yield of the diol in the case where the production cost is relatively low.

A hydrogenolysis process is disclosed for directly converting a sugar feed comprised of a high fructose feedstock, a high sucrose feedstock, or a combination of these to a mixed lower polyols product including both propylene glycol and ethylene glycol. The process provides greater propylene glycol selectivity than ethylene glycol selectivity such that the propylene glycol is present to a greater extent than the ethylene glycol in the mixed lower polyols product. The sugar feed and a source of hydrogen are supplied to a reaction vessel and reacted in the presence of a hydrogenolysis catalyst comprising molybdenum (Mo) and ruthenium (Ru).

A hydrogenolysis process is disclosed for directly converting a sugar feed comprised of a high fructose feedstock, a high sucrose feedstock, or a combination of these to a mixed lower polyols product including both propylene glycol and ethylene glycol. The process provides greater propylene glycol selectivity than ethylene glycol selectivity such that the propylene glycol is present to a greater extent than the ethylene glycol in the mixed lower polyols product. The sugar feed and a source of hydrogen are supplied to a reaction vessel and reacted in the presence of a hydrogenolysis catalyst comprising molybdenum (Mo) and ruthenium (Ru).

Use of diverse biomass feedstock in a process for the recovery of target C5 and C6 alditols and target glycols via staged hydrogenation and hydrogenolysis processes is disclosed. Particular alditols of interest include, but are not limited to, xylitol and sorbitol. Various embodiments of the present invention synergistically improve overall recovery of target alditols and/or glycols from a mixed C5/C6 sugar stream without needlessly driving total recovery of the individual target alditols and/or glycols. The result is a highly efficient, low complexity process having enhanced production flexibility, reduced waste and greater overall yield than conventional processes directed to alditol or glycol production.

Use of diverse biomass feedstock in a process for the recovery of target C5 and C6 alditols and target glycols via staged hydrogenation and hydrogenolysis processes is disclosed. Particular alditols of interest include, but are not limited to, xylitol and sorbitol. Various embodiments of the present invention synergistically improve overall recovery of target alditols and/or glycols from a mixed C5/C6 sugar stream without needlessly driving total recovery of the individual target alditols and/or glycols. The result is a highly efficient, low complexity process having enhanced production flexibility, reduced waste and greater overall yield than conventional processes directed to alditol or glycol production.

Use of diverse biomass feedstock in a process for the recovery of target C5 and C6 alditols and target glycols via staged hydrogenation and hydrogenolysis processes is disclosed. Particular alditols of interest include, but are not limited to, xylitol and sorbitol. Various embodiments of the present invention synergistically improve overall recovery of target alditols and/or glycols from a mixed C5/C6 sugar stream without needlessly driving total recovery of the individual target alditols and/or glycols. The result is a highly efficient, low complexity process having enhanced production flexibility, reduced waste and greater overall yield than conventional processes directed to alditol or glycol production.

The present invention relates to a method for preparing a compound of formula (I). The present invention also relates to compounds of formula (A) or a compound in the form of a stereoisomer. The present invention further relates to the use of a compound of formula (A) as aroma chemical.

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