Patent ID: 6207809
Filing Date: 2001-03-27
Classification: C07C

Abstract:
A process for the preparation of aqueous solutions of diazonium salts of the formula (1) ##STR3##in which some or all of the amino groups are in protonated form,R.sup.1, R.sup.2, R.sup.3 and R.sup.4, independently of one another, are hydrogen, a C.sub.1 -C.sub.16 -alkyl, C.sub.3 -C.sub.7 -cycloalkyl, C.sub.2 -C.sub.16 -alkenyl, aryl or a 5- to 6-membered aliphatic or aromatic heterocycle, which are optionally substituted by one or more C.sub.1 -C.sub.4 alkyl radicals, halogen atoms or groups of the formula .dbd.O, --OR', --NR'R"", --SR', --COR', --COOR', --CONR'R"", --NR'CONR""R'"" or --SO.sub.2 NR'R"", where R', R"", R'"" are hydrogen or a C.sub.1 -C.sub.10 -alkyl, C.sub.3 -C.sub.7 -cycloalkyl, C.sub.2 -C.sub.16 -alkenyl, aryl or a 5- to 6-membered aliphatic or aromatic heterocycle, or where R' and R"", or R"" and R'"", or R.sup.3 and R.sup.4 together with the adjacent N atom form a 5- or 6-membered aliphatic or aromatic heterocycle, and R.sup.1 and R.sup.2 may additionally be halogen or groups of the formula --OR', --NR'R""R'"", --SR', --COR', --COOR', --CONR'R"", --SO.sub.3 H.sub.2, --PO.sub.4 H.sub.2, --NR'CONR""R'"" or --SO.sub.2 NR'R"";A, A' and A"", independently of one another, are a divalent group of the formula --O--, --NR'--, --S--, --CO--, --COO--, --CONR'--, --NR'CONR""-- or --SO.sub.2 NR'--;B, B' and B"", independently of one another, are a substituted or unsubstituted C.sub.1 -C.sub.14 -alkylene, C.sub.3 -C.sub.7 -cycloalkylene, C.sub.2 -C.sub.14 -alkenylene, arylene or heteroarylene radical,or B, B' or B"" form, together with R.sup.3 and/or R.sup.4 and the adjacent N atom a 5- to 7-membered heterocycle;Y.sup.- is F.sup.-, Cl.sup.-, Br.sup.-, HSO.sub.4.sup.-, 1/2SO.sub.4.sup.2-, H.sub.2 PO.sub.4.sup.-, 1/2HPO.sub.4.sup.2-, 1/3PO.sub.4.sup.3-, an anion of a pyro-, meta- or poly-phosphoric acid, BF.sub.4.sup.-, PF.sub.6.sup.-, HCO.sub.3.sup.-, 1/2CO.sub.3.sup.2-, NO.sub.2.sup.-, NO.sub.3.sup.-, formate, acetate, propionate, R""""SO.sub.4.sup.-, R""""SO.sub.3.sup.- or R""""COO.sup.-, where R"""" is a substituted or unsubstituted C.sub.1 -C.sub.21 -alkyl or aryl radical;k, l and m, independently of one another, are the number 0, 1, 2 or 3;n, o and p, independently of one another, are the numbers 0 or 1;x is an integer from 1 to 3; andy and z are each an integer from 1 to 4, where the sum x+y+z is 3 to 5, which comprisesreacting an aqueous solution of a water-soluble salt of the aromatic nitro compound of the formula (2), ##STR4##with hydrogen and in the presence of a catalyst which catalyzes the reduction of aromatic nitro groups to amino groups, and diazotizing the aromatic amine formed in the process in the aqueous solution with a diazotization reagent to give the diazonium salt.