Ciba-geigy Corporation

Hugo Illy

Rudolf Kirchmayr

Werner Fussenegger

Andreas Schmidt

Andre Schmitter

Ronald Salathe

Bjorn Schliebs

Rudolf Schwabe

Wilhelm Hess

The substituent X in the phenols of the formula: ##STR1## wherein R.sub.1 to R.sub.4 are hydrogen or unsubstituted or substituted alkyl, alkenyl or alkynyl, and X is secondary or tertiary alkyl of 3 to 9 carbon atoms, can be removed by heating said phenols in the presence of an alkali metal hydrogensulfate.

Process for the preparation of substituted phenols

The present invention relates to a process for the preparation of pentaerythritol esters of phosphorous acid derivatives by reacting pentaerythritol with a phosphorous trihalide and a phenol in the presence of a quaternary salt or a polyether. The use of such catalysts is not only able to improve the yield, but also makes it possible for the entire process to be carried out in one step by adding the phenol at the start of the reaction of pentaerythritol with the phosphorous halide.

Process for the preparation of cyclic phosphites

A process for foaming thermoplastic materials by adding to the plastics material 0.05 to 5 percent by weight of a dioxazolone of the formula I ##STR1## in which n is 1, 2 or 3, and when n is 1

Process for foaming plastics

Aromatic sulfonic acid hydrazides and semicarbazides having a sterically hindered phenol group are usable as blowing agents in the manufacture of foamed plastics articles. On heating to about 200 to 300.degree. C. they are splitting off nitrogen and the residue remaining in the foam acts as stabilizer against thermo-oxidative degradation of the plastic material.

Aromatic sulfonyl hydrazides and semicarbazides as chemical blowing

Tris-tetrazoles of formula I, ##STR1## wherein A is alkylene and R is hydrogen, alkyl or phenyl, are suitable blowing agents for thermoplastic resins, especially for polycarbonates and aromatic polyethers. The foaming process can be carried out at a temperature range of 230.degree. to 300.degree. C., the resulting foamed articles have a fine and homogeneous cellular structure. The tris-tetrazoles I can be synthesized from the corresponding tris-nitriles or tris-imidchlorides by reaction with an alkali azide.

Tris-tetrazoles as chemical blowing agents

Bis-tetrazoles wherein the two tetrazole rings are bridged by a direct bond or a divalent organic residue in 5,5'-position or in 1,1'-position have been found to be suitable as blowing agents for thermoplastic resins. They decompose at temperatures of about 230 to 300.degree. C. and therefore can be used for the expansion of resins which are processed at such temperatures, for instance polypropylene, polycarbonates, polyphenyleneoxides or polyamides. Preferred are bis-tetrazoles bridges by aliphatic or araliphatic residues. The expansion can be carried out in an extruder or an injection moulding device.

Bis-tetrazoles as chemical blowing agents for foaming thermoplastic

Tris-tetrazoles of formula I, ##STR1## wherein A is alkylene and R is hydrogen, alkyl or phenyl, are suitable blowing agents for thermoplastic resins, especially for polycarbonates and aromatic polyethers. The foaming process can be carried out at a temperature range of 230 to 300.degree. C, the resulting foamed articles have a fine and homogenous cellular structure. The tris-tetrazoles I can be sythesized from the corresponding tris-nitriles or tris-imidchlorides by reaction with an alkali azide.

Sulfonyltetrazoles of formula I, ##STR1## wherein n is 1 or 2, A is alkylene and R is a mono- or divalent hydrocarbon residue, are usable as blowing agents for thermoplastic polymers. These compounds decompose at temperatures above 200.degree. C, therefore they can be used preferably for foaming thermoplasts of higher softening temperature such as aromatic polycarbonates, polyesters or polyethers.

Sulphonyltetrazoles as chemical blowing agents

3-Hydroxy-5-phosphono-1,2-oxaphospholanes can be synthesized from .beta.-dicarbonyl compounds by reaction with 2 moles of an diorganophosphite. The products are usable as flameproofing agents for plastics, particularly for polyurethanes and epoxide resins which are able to react with the hydroxyl group of the oxaphospholanes.

Growing community of inventors

Reinach, Switzerland

Hugo Illy