Method for the hydrogenation of unsaturated polymers containing double bonds
View Patent ↗The present invention relates to a method for the hydrogenation of unsaturated polymers containing double bonds, the unsaturated polymers present in latex form being hydrogenated in the presence of a metal-containing colloid.
1. A method for the hydrogenation of unsaturated polymers containing double bonds, comprising the steps of: (a) preparing a metal-containing colloid in the presence of an unsaturated polymer present in latex form and a reducing agent selected from the group consisting of hydrogen, complex hydrides, reductive inorganic compounds, organic compounds, alkali metal formates, finely divided non-noble metals and mixtures thereof, whereby the pH during the preparation of the metal-containing colloid is in the range of from 3 to 6, and (b) hydrogenating and hydrogenating the colloid containing latex mixture obtained, and separating the metal containing colloid from the latex, and isolating the polymer latex.
2. The method as claimed in claim 1 , characterized in that unsaturated polymers containing double bonds which are used are those which are composed of conjugated dienes or of from 1 to 5% by weight of conjugated dienes and from 95 to 99% by weight of unsaturated monomers containing vinyl groups.
3. The method as claimed in claim 1 , characterized in that the concentration of the polymer latex to be hydrogenated is from 1 to 50% by weight, based on the aqueous emulsion.
4. The method as claimed in claim 1 , characterized in that metal salts or metal complexes which are based on metals of group VIIIB of the Periodic Table of the Elements (Mendeleev) and of ruthenium or rhodium are used for the preparation of the metal-containing colloid.
5. The method as claimed in claim 1 , characterized in that the hydrogenation of the colloid-containing latex mixture is carried out at pressures in the range of from 0.1 to 100 bar and at temperatures in the range of from 25 to 100° C.
6. The method as claimed in claim 1 , wherein the reducing agent is selected from the group consisting of hydrogen, NaBH4, hydroxylammonium hydrochloride, hydrazine and hydrazine hydrate, formaldehyde and acetaldehyde, formic acid and sodium formate, zinc powder and mixtures thereof.
7. The method as claimed in claim 1 , wherein the reducing agent is selected from the group consisting of hydrogen, sodium borohydride, and hydrazine hydrate and mixtures thereof.
8. The method as claimed in claim 1 , wherein the reducing agent is added in the presence of a hydrogen atmosphere.