Riedel-De Haen Aktiengesellschaft

Kurt Eiglmeier

Joachim Schulz

Reinhard Knieps

Benzophenone derivatives having at least one hydroxyl group in the ortho-position relative to the carbonyl group are used for stabilizing numerous substrates against the action of UV light. 1,3-bis-(4-Benzoyl-3-hydroxyphenoxy)-2-propanol is a photo-absorber containing two benzophenone groups. Particularly suitable stabilizers are esters of this substituted propanol with unsaturated carboxylic acids, for example esters of acrylic acid and methacrylic acid. These compounds are prepared by esterifying the substituted propanol with an unsaturated acid or by esterifying the substituted propanol with a saturated acid containing a reactive methylene group and subjecting the product to subsequent condensation with a keto compound. They can be polymerized and are suitable for the preparation of homopolymers and copolymers.

UV light stabilizer based on benzophenone

Substituted bromofluorobenzene, wherein the fluorine is in para-position and the bromine in meta-position to another substituent, is prepared by direct bromination of the corresponding fluorobenzene derivative. Bromination is advantageously carried out in the presence of a catalyst, preferably a metal or metal salt. The elementary bromine is used in an amount of 0.9 to 1.3 mols per mol of fluorobenzene derivative and the reaction temperature is between 20.degree. and 200.degree. C. The bromofluorobenzene derivatives are suitable for the synthesis of medicaments and plant protective agents.

Growing community of inventors

Seelze, Germany

Kurt Eiglmeier