[Objective] An object is to provide a method for producing a diol by which diols having a favorable color scale and containing a reduced amount of an unsaturated aliphatic hydrocarbon can be produced.

[Solution] A method for producing a diol, including a) supplying metaboric acid, a saturated aliphatic hydrocarbon and a reaction gas containing molecular oxygen to a reactor and performing liquid-phase oxidation of the saturated aliphatic hydrocarbon with the reaction gas containing molecular oxygen in the presence of metaboric acid to obtain a reaction liquid containing an oxide, b) esterifying the oxide to obtain a reaction liquid containing a borate compound, c) separating the reaction liquid containing a borate compound into an unreacted saturated aliphatic hydrocarbon and a distillation residue by distillation, d) separating the distillation residue into orthoboric acid and an organic layer by hydrolysis, e) separating the organic layer into an alkali aqueous solution layer and a crude alcohol layer by saponification with an alkali, and f) performing first distillation on the crude alcohol layer to remove a monoalcohol, and then performing second distillation on the residual liquid under conditions of a temperature of lower than 250° C. and a residence time of shorter than 60 minutes.

[Objective] An object is to provide a method for producing a diol by which diols having a favorable color scale and containing a reduced amount of an unsaturated aliphatic hydrocarbon can be produced.

[Solution] A method for producing a diol, including a) supplying metaboric acid, a saturated aliphatic hydrocarbon and a reaction gas containing molecular oxygen to a reactor and performing liquid-phase oxidation of the saturated aliphatic hydrocarbon with the reaction gas containing molecular oxygen in the presence of metaboric acid to obtain a reaction liquid containing an oxide, b) esterifying the oxide to obtain a reaction liquid containing a borate compound, c) separating the reaction liquid containing a borate compound into an unreacted saturated aliphatic hydrocarbon and a distillation residue by distillation, d) separating the distillation residue into orthoboric acid and an organic layer by hydrolysis, e) separating the organic layer into an alkali aqueous solution layer and a crude alcohol layer by saponification with an alkali, and f) performing first distillation on the crude alcohol layer to remove a monoalcohol, and then performing second distillation on the residual liquid under conditions of a temperature of lower than 250° C. and a residence time of shorter than 60 minutes.

[Objective] An object is to provide a method for producing a diol by which diols having a favorable color scale and containing a reduced amount of an unsaturated aliphatic hydrocarbon can be produced.

[Solution] A method for producing a diol, including a) supplying metaboric acid, a saturated aliphatic hydrocarbon and a reaction gas containing molecular oxygen to a reactor and performing liquid-phase oxidation of the saturated aliphatic hydrocarbon with the reaction gas containing molecular oxygen in the presence of metaboric acid to obtain a reaction liquid containing an oxide, b) esterifying the oxide to obtain a reaction liquid containing a borate compound, c) separating the reaction liquid containing a borate compound into an unreacted saturated aliphatic hydrocarbon and a distillation residue by distillation, d) separating the distillation residue into orthoboric acid and an organic layer by hydrolysis, e) separating the organic layer into an alkali aqueous solution layer and a crude alcohol layer by saponification with an alkali, and f) performing first distillation on the crude alcohol layer to remove a monoalcohol, and then performing second distillation on the residual liquid under conditions of a temperature of lower than 250° C. and a residence time of shorter than 60 minutes.

[Objective] An object is to provide a method for producing a diol by which diols having a favorable color scale and containing a reduced amount of an unsaturated aliphatic hydrocarbon can be produced. [Solution] A method for producing a diol, including a) supplying metaboric acid, a saturated aliphatic hydrocarbon and a reaction gas containing molecular oxygen to a reactor and performing liquid-phase oxidation of the saturated aliphatic hydrocarbon with the reaction gas containing molecular oxygen in the presence of metaboric acid to obtain a reaction liquid containing an oxide, b) esterifying the oxide to obtain a reaction liquid containing a borate compound, c) separating the reaction liquid containing a borate compound into an unreacted saturated aliphatic hydrocarbon and a distillation residue by distillation, d) separating the distillation residue into orthoboric acid and an organic layer by hydrolysis, e) separating the organic layer into an alkali aqueous solution layer and a crude alcohol layer by saponification with an alkali, and f) performing first distillation on the crude alcohol layer to remove a monoalcohol, and then performing second distillation on the residual liquid under conditions of a temperature of lower than 250° C. and a residence time of shorter than 60 minutes.

[Objective] An object is to provide a method for producing a diol by which diols having a favorable color scale and containing a reduced amount of an unsaturated aliphatic hydrocarbon can be produced. [Solution] A method for producing a diol, including a) supplying metaboric acid, a saturated aliphatic hydrocarbon and a reaction gas containing molecular oxygen to a reactor and performing liquid-phase oxidation of the saturated aliphatic hydrocarbon with the reaction gas containing molecular oxygen in the presence of metaboric acid to obtain a reaction liquid containing an oxide, b) esterifying the oxide to obtain a reaction liquid containing a borate compound, c) separating the reaction liquid containing a borate compound into an unreacted saturated aliphatic hydrocarbon and a distillation residue by distillation, d) separating the distillation residue into orthoboric acid and an organic layer by hydrolysis, e) separating the organic layer into an alkali aqueous solution layer and a crude alcohol layer by saponification with an alkali, and f) performing first distillation on the crude alcohol layer to remove a monoalcohol, and then performing second distillation on the residual liquid under conditions of a temperature of lower than 250° C. and a residence time of shorter than 60 minutes.

[Objective] An object is to provide a method for producing a diol by which diols having a favorable color scale and containing a reduced amount of an unsaturated aliphatic hydrocarbon can be produced. [Solution] A method for producing a diol, including a) supplying metaboric acid, a saturated aliphatic hydrocarbon and a reaction gas containing molecular oxygen to a reactor and performing liquid-phase oxidation of the saturated aliphatic hydrocarbon with the reaction gas containing molecular oxygen in the presence of metaboric acid to obtain a reaction liquid containing an oxide, b) esterifying the oxide to obtain a reaction liquid containing a borate compound, c) separating the reaction liquid containing a borate compound into an unreacted saturated aliphatic hydrocarbon and a distillation residue by distillation, d) separating the distillation residue into orthoboric acid and an organic layer by hydrolysis, e) separating the organic layer into an alkali aqueous solution layer and a crude alcohol layer by saponification with an alkali, and f) performing first distillation on the crude alcohol layer to remove a monoalcohol, and then performing second distillation on the residual liquid under conditions of a temperature of lower than 250° C. and a residence time of shorter than 60 minutes.

Catalysts for producing one or more oxygenated products from methane are provided. In embodiments, the catalyst comprises active sites comprising isolated, cationic transition metal M atoms covalently bound to internal surfaces of pores of a porous metal M silicate, wherein M is Rh or Ir, and further wherein the M atoms are bound to five oxygen (O) atoms. Methods for making and using the catalysts are also provided.

Catalysts for producing one or more oxygenated products from methane are provided. In embodiments, the catalyst comprises active sites comprising isolated, cationic transition metal M atoms covalently bound to internal surfaces of pores of a porous metal M silicate, wherein M is Rh or Ir, and further wherein the M atoms are bound to five oxygen (O) atoms. Methods for making and using the catalysts are also provided.

Catalysts for producing one or more oxygenated products from methane are provided. In embodiments, the catalyst comprises active sites comprising isolated, cationic transition metal M atoms covalently bound to internal surfaces of pores of a porous metal M silicate, wherein M is Rh or Ir, and further wherein the M atoms are bound to five oxygen (O) atoms. Methods for making and using the catalysts are also provided.

Systems and methods are provided for direct methane conversion to methanol. The methods can include exposing methane to an oxidant, such as O.sub.2, in a solvent at conditions that are substantially supercritical for the solvent while having a temperature of about 310 C. or less, or about 300 C. or less, or about 290 C. or less. The solvent can correspond to an electron donor solvent that, when in a supercritical state, can complex with O.sub.2. By forming a complex with the O.sub.2, the supercritical electron donor solvent can facilitate conversion of methane to methanol at short residence times while reducing or minimizing further oxidation of the methanol to other products.