The invention relates to a method for the catalytic generation of formic acid at an oxygen partial pressure below 1 bar and regeneration of the catalyst used therefor.

The synthesis, structure, and reactivity of a family of iridium-based molecular cluster complexes, including neutron and X-ray single-crystal diffraction measurements, are provided. It is found that one complex, which includes an Ir.sub.3H.sub.6(.sup.3H) trinuclear core, exhibits reactivity for reversible CO.sub.2 hydrogenation via hydride transfer. This reactivity is unlike previous reports of one known Ir.sub.3H.sub.6(.sup.3H) complex, which is inert.

Process for the co-production of acetic acid and dimethyl ether with reduced formic acid content by distilling a mixture containing dimethyl ether, methanol and methyl formate, separating methyl formate from the mixture to recover dimethyl ether and methanol, and catalytically reacting the methanol and methyl acetate to produce a reaction product of acetic acid an dimethyl ether.

Process for the co-production of acetic acid and dimethyl ether with reduced formic acid content by distilling a mixture containing dimethyl ether, methanol and methyl formate, separating methyl formate from the mixture to recover dimethyl ether and methanol, and catalytically reacting the methanol and methyl acetate to produce a reaction product of acetic acid an dimethyl ether.

The presently disclosed and/or claimed inventive concept(s) relates generally to the reduction of carbon dioxide by heterogeneous catalysis. More particularly, but not by way of limitation, the presently disclosed and/or claimed inventive concept(s) relates to the reduction of carbon dioxide by heterogeneous catalysis with a heterogeneous hydrogenation catalyst comprising structurally frustrated Lewis pairs, wherein, for example but not by way of limitation, formic acid is produced and hydrocarbons are indirectly produced. In one non-limiting embodiment, the heterogeneous catalyst comprises hexagonal boron nitride (h-BN) having structurally frustrated Lewis pairs therein.

The presently disclosed and/or claimed inventive concept(s) relates generally to the reduction of carbon dioxide by heterogeneous catalysis. More particularly, but not by way of limitation, the presently disclosed and/or claimed inventive concept(s) relates to the reduction of carbon dioxide by heterogeneous catalysis with a heterogeneous hydrogenation catalyst comprising structurally frustrated Lewis pairs, wherein, for example but not by way of limitation, formic acid is produced and hydrocarbons are indirectly produced. In one non-limiting embodiment, the heterogeneous catalyst comprises hexagonal boron nitride (h-BN) having structurally frustrated Lewis pairs therein.

In some variations, the invention provides a process for producing furfural, 5-hydroxymethylfurfural, and/or levulinic acid from cellulosic biomass, comprising: fractionating the feedstock in the presence of a solvent for lignin, sulfur dioxide, and water, to produce a liquor containing hemicellulose, cellulose-rich solids, and lignin; hydrolyzing the hemicellulose contained in the liquor, to produce hemicellulosic monomers; dehydrating the hemicellulose to convert at least a portion of C.sub.5 hemicelluloses to furfural and to convert at least a portion of C.sub.6 hemicelluloses to 5-hydroxymethylfurfural; converting at least some of the 5-hydroxymethylfurfural to levulinic acid and formic acid; and recovering at least one of the furfural, the 5-hydroxymethylfurfural, or the levulinic acid. Other embodiments provide a process for dehydrating hemicellulose to convert oligomeric C.sub.5 hemicelluloses to furfural and to convert oligomeric C.sub.6 hemicelluloses to 5-hydroxymethylfurfural. The furfural may be converted to succinic acid, or to levulinic acid, for example.

In some variations, the invention provides a process for producing furfural, 5-hydroxymethylfurfural, and/or levulinic acid from cellulosic biomass, comprising: fractionating the feedstock in the presence of a solvent for lignin, sulfur dioxide, and water, to produce a liquor containing hemicellulose, cellulose-rich solids, and lignin; hydrolyzing the hemicellulose contained in the liquor, to produce hemicellulosic monomers; dehydrating the hemicellulose to convert at least a portion of C.sub.5 hemicelluloses to furfural and to convert at least a portion of C.sub.6 hemicelluloses to 5-hydroxymethylfurfural; converting at least some of the 5-hydroxymethylfurfural to levulinic acid and formic acid; and recovering at least one of the furfural, the 5-hydroxymethylfurfural, or the levulinic acid. Other embodiments provide a process for dehydrating hemicellulose to convert oligomeric C.sub.5 hemicelluloses to furfural and to convert oligomeric C.sub.6 hemicelluloses to 5-hydroxymethylfurfural. The furfural may be converted to succinic acid, or to levulinic acid, for example.

Provided herein is a process for producing a compound of formula (I), or a salt thereof: (I) catalyst. Also provided herein are catalysts which find use in the process.

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Provided herein is a process for producing a compound of formula (I), or a salt thereof: (I) catalyst. Also provided herein are catalysts which find use in the process.

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