Disclosed is a catalyst based on synthetic silica, in a heterogeneous catalysis method, to promote the effective conversion of residual glycerin, resulting from the production of biodiesel, into formic acid with high selectivity and stability, in a continuous flow reaction. The conversion of residual glycerin occurs by homogeneous catalysis, by the action of components remaining from the synthesis of biodiesel, with the formation of major compounds, such as formic acid, cyclic ethers and diglycerol, in continuous flow and reflow reactions. The reaction can also be carried out by adding sodium salts in the homogeneous catalytic conversion process of commercial glycerin. The process values the residual glycerin, without the need for purification before its transformation into products with high added value, but of renewable origin, adding more interest and potential.

Disclosed is a catalyst based on synthetic silica, in a heterogeneous catalysis method, to promote the effective conversion of residual glycerin, resulting from the production of biodiesel, into formic acid with high selectivity and stability, in a continuous flow reaction. The conversion of residual glycerin occurs by homogeneous catalysis, by the action of components remaining from the synthesis of biodiesel, with the formation of major compounds, such as formic acid, cyclic ethers and diglycerol, in continuous flow and reflow reactions. The reaction can also be carried out by adding sodium salts in the homogeneous catalytic conversion process of commercial glycerin. The process values the residual glycerin, without the need for purification before its transformation into products with high added value, but of renewable origin, adding more interest and potential.

An aqueous iron sulfide dissolver including zinc, chromium, a methoxybenzoic acid, formic acid, acetic acid, and hydrochloric acid. The iron sulfide dissolver is made by combining these components, and dissolves compounds including iron sulfide upon contact. Evolved hydrogen sulfide reacts with the methoxybenzoic acid to yield solubilized methanethiol as an intermediate product, which is further oxidized to yield dissolved dimethyl disulfide.

An aqueous iron sulfide dissolver including zinc, chromium, a methoxybenzoic acid, formic acid, acetic acid, and hydrochloric acid. The iron sulfide dissolver is made by combining these components, and dissolves compounds including iron sulfide upon contact. Evolved hydrogen sulfide reacts with the methoxybenzoic acid to yield solubilized methanethiol as an intermediate product, which is further oxidized to yield dissolved dimethyl disulfide.

An arrangement for separating chemicals comprises a first distillation column (100) and the first distillation column (100) receives a mixture that comprises water and at least two organic acids and extractant that comprises at least one of the following: hexanol, an ester of hexanol with said at least one organic acid and 2-methylpentanol. The first distillation column (100) forms a heterogeneous azeotrope of water and extractant at its top (104) on the basis of reactive heteroazeotropic extractive distillation not controlling chemical reactions between the extractant and said at least two organic acids, said first distillation column (100) removing the azeotrope through its top (104) for separating water from the organic acid.

An arrangement for separating chemicals comprises a first distillation column (100) and the first distillation column (100) receives a mixture that comprises water and at least two organic acids and extractant that comprises at least one of the following: hexanol, an ester of hexanol with said at least one organic acid and 2-methylpentanol. The first distillation column (100) forms a heterogeneous azeotrope of water and extractant at its top (104) on the basis of reactive heteroazeotropic extractive distillation not controlling chemical reactions between the extractant and said at least two organic acids, said first distillation column (100) removing the azeotrope through its top (104) for separating water from the organic acid.

The invention relates to a method for catalytically producing formic acid and regenerating the catalyst used in the process. A vanadyl ion, vandate ion, or polyoxometallate ion, which is used as the catalyst, of the general formula [PMo.sub.xV.sub.yO.sub.40].sup.n is brought into contact with an alpha hydroxyl aldehyde, an alpha hydroxy carboxylic acid, a carbohydrate, a glycoside, or a polymer, which contains a carbon chain and which comprises at least one OH group that is bound to the carbon chain as a substituent in a repeating manner and/or an O, N, or S atom contained in the carbon chain in a repeating manner, in a liquid solution (12) in a vessel (10) at a temperature above 70 C. and below 160 C., wherein 6x11, 1y6, 3<n<10, and x+y=12, where n, x, and y is each a whole number. The catalyst reduced in the process is returned to its starting state by oxidation. For this purpose, the solution (12) is brought into contact with a gas (18) which contains a volume percent of oxygen of at least 18% at a pressure of at least 2 bar and maximally 16 bar by means of a mixing device or via a liquid-non-permeable gas-permeable membrane. CO and/or CO.sub.2 resulting during the reaction and merging with the gas (18) is discharged in such a quantity that the volume percent of CO and CO.sub.2 combined does not exceed 80% in the gas (18).

The invention relates to a method for catalytically producing formic acid and regenerating the catalyst used in the process. A vanadyl ion, vandate ion, or polyoxometallate ion, which is used as the catalyst, of the general formula [PMo.sub.xV.sub.yO.sub.40].sup.n is brought into contact with an alpha hydroxyl aldehyde, an alpha hydroxy carboxylic acid, a carbohydrate, a glycoside, or a polymer, which contains a carbon chain and which comprises at least one OH group that is bound to the carbon chain as a substituent in a repeating manner and/or an O, N, or S atom contained in the carbon chain in a repeating manner, in a liquid solution (12) in a vessel (10) at a temperature above 70 C. and below 160 C., wherein 6x11, 1y6, 3<n<10, and x+y=12, where n, x, and y is each a whole number. The catalyst reduced in the process is returned to its starting state by oxidation. For this purpose, the solution (12) is brought into contact with a gas (18) which contains a volume percent of oxygen of at least 18% at a pressure of at least 2 bar and maximally 16 bar by means of a mixing device or via a liquid-non-permeable gas-permeable membrane. CO and/or CO.sub.2 resulting during the reaction and merging with the gas (18) is discharged in such a quantity that the volume percent of CO and CO.sub.2 combined does not exceed 80% in the gas (18).

The invention relates to a method for catalytically producing formic acid and regenerating the catalyst used in the process. A vanadyl ion, vandate ion, or polyoxometallate ion, which is used as the catalyst, of the general formula [PMo.sub.xV.sub.yO.sub.40].sup.n is brought into contact with an alpha hydroxyl aldehyde, an alpha hydroxy carboxylic acid, a carbohydrate, a glycoside, or a polymer, which contains a carbon chain and which comprises at least one OH group that is bound to the carbon chain as a substituent in a repeating manner and/or an O, N, or S atom contained in the carbon chain in a repeating manner, in a liquid solution (12) in a vessel (10) at a temperature above 70 C. and below 160 C., wherein 6x11, 1y6, 3<n<10, and x+y=12, where n, x, and y is each a whole number. The catalyst reduced in the process is returned to its starting state by oxidation. For this purpose, the solution (12) is brought into contact with a gas (18) which contains a volume percent of oxygen of at least 18% at a pressure of at least 2 bar and maximally 16 bar by means of a mixing device or via a liquid-non-permeable gas-permeable membrane. CO and/or CO.sub.2 resulting during the reaction and merging with the gas (18) is discharged in such a quantity that the volume percent of CO and CO.sub.2 combined does not exceed 80% in the gas (18).

The invention relates to a process to separate formic acid from methyltetrahydrofuran (MTHF) said process comprising subjecting a composition comprising formic acid and MTHF to distillation, characterized in that the process comprises adding water to said distillation. This allows for cost-efficient recovery and recycling of MTHF, for example in process to produce and recover formic acid from a biomass hydrolysate.