Process for the preparation of carbodimides

Claim 1

IN THE PROCESS OF PREPARING ORGANIC CARBODIMIDES FROM ORGANIC ISOCYANATES FREE OF SUBSTITUENTS OF ZEREWITINOFF ACTIVE HYDROGEN, SAID ORGANIC ISOCYANATE BEING SELECTED FROM THE GROUP CONSISTING OF BENZENE ISOCYANATES, LOWER ALKYL BENZENE ISOCYANATES, LOWER ALKOXY BENZENE ISOCYANATES, HALOBENZENE ISOCYANATES, NITROBENZENE ISOCYANATES, NAPHTHALENE ISOCYANATES, BIPENYL ISOCYANATES, DIPHENYL ETHER ISOCYANATES, ALKANE ISOCYANATES CONTAINING FROM 1 TO 18 CARBONS, ALKENE ISOCYANATES, CONTAINING FROM 3 TO 18 CARBONS, CYCLOHEXANE ISOCYANATES, LOWER ALKYL CYCLOHEXANE ISOCYANATES, AND DECAHYDRONAPHTHALENE ISOCYANATES, ONE TO THREE ISOCYANATE GROUP BEING PRESENT IN SAID ISOCYANATE, THE IMPROVEMENT WHICH COMPRISES HEATING, TOGETHER SAID IXOCYANATE, AT A TEMPERATURE IN THE RANGE OF 30* TO 190*C., FROM 0.001 TO 0.1 MOLE PER MOLE OF SAID ISOCYANATE OF A CATALYST SELECTED FROM THE GROUP CONSISTING OF (1) PHOSPHATES OF THE FORMULA (RO)3PO, (2) PHOSPHATES OF THE FORMULA (R"O)3PO, (3) PHOSPHONATES OF THE FORMULA (RO)2P(O)R'', (4) PHOSPHORAMIDES OF THE FORMULA (R2N)3PO, (5) PHOSPHONAMIDES OF THE FORMULA (R2N)2P(O)R'' AND (6) TRIARYLAMIDOPHOSPHATES OF THE FORMULA (R"NH)3PO, IN WHICH CATALYST R AND R'' ARE SELECTED FROM THE GROUP CONSISTING OF ALKYL GROUPS OF 1 TO 12 CARBONS, ALKENYL GROUPS OF 2 TO 12 CARBONS AND HALOALKYL GROUPS OF 1 TO 12 CARBONS, AND R" IS SELECTED FROM THE GROUP CONSISTING OF PHENYL, LOWER ALKYL PHENYL, LOWER ALKOXY PHENYL AND HALO PHENYL GROUPS, SAID ORGANIC ISOCYANATE BEING HEATED IN THE PRESENCE OF SAID CATALYST UNTIL THE EVOLUTION OF CARBON DIOXIDE IS SUBSTANTIALLY COMPLETE.