Reaction of a solution comprising a mixture

A method of increasing the concentration of one or more compounds in a solution comprising a mixture of at least two chemical compounds which are in chemical equilibrium with one another selected from the group consisting of aqueous formaldehyde solution, solutions of alkyl thiols in sulfur and solutions of oligomer mixtures, with the exception of the reaction of a formaldehyde solution with aniline in the presence of acid catalysts, wherein the formaldehyde solution comprises polyoxymethylene glycols or polyoxymethylene glycols and monomeric formaldehyde or polyoxymethylene glycols and methylene glycol or polyoxymethylene glycols and monomeric formaldehyde and methylene glycol, which method comprises the following steps:

• (a) fractionating the solution by means of a separation method to give at least two fractions in which different chemical compounds of the mixture are present in increased concentrations compared to the chemical equilibrium;
• and
• (b) reacting at least one of the compounds of increased concentration with a further chemical compound or compounds before the chemical equilibrium is fully established in at least one of the fractions, and recovering the desired compound(s).

A method of reacting an aqueous formaldehyde solution comprising a mixture of chemical compounds, including formaldehyde, methylene glycol and oligomers made up of at least two methylene glycol units, with at least one further chemical compound selected from the group consisting of acetylene, formaldehyde and higher aldehydes, CO, olefins, amines, hydroxylamine and diols, which method comprises the following steps:

• (a) fractionation of said solution by means of a separation method to give at least two fractions in which fractions the chemical compounds of the mixture are present in increased concentrations compared to the chemical equilibrium, which said solution shows before this fractionation step and
• (b) reaction of one fraction with the further chemical compound or compounds before the chemical equilibrium is fully reestablished,
• with the exception of the reaction of a formaldehyde solution with aniline in the presence of acid catalysts, wherein the formaldehyde solution comprises polyoxymethylene glycols or polyoxymethylene glycols and monomeric formaldehyde or polyoxymethylene glycols and methylene glycol or polyoxymethylene glycols and monomeric formaldehyde and methylene glycol.

A method of increasing the concentration of one or more compounds in a solution comprising a mixture of water, formaldehyde, methylene glycol and oligomers made up of at least two methylene polymethylene glycols, which compounds are in chemical equilibrum, which method comprises the following steps:

• (a) fractioning said solution by means of a separation method to give at least two fractions in which fractions the chemical compounds of the mixture are present in increased concentrations compared to the chemical equilibrium, and
• (b) reacting the compounds of increased concentration in at least one fraction with a further chemical compound or compound(s) before the chemical equilibrium is fully reestablished, and recovering the desired compound(s).