Method for preparing polyamine compounds
View Patent ↗A method for preparing a compound having formula (II) wherein R 1 and R 2 independently are methyl or ethyl, or R 1 and R 2 combine to form a C 5 or C 6 cycloalkyl or cycloalkenyl group. The method includes a step of combining R 1 R 2 CHNO 2 , glutaraldehyde and an amine. The compound is useful in coating compositions and other applications for pH adjustment.
1. A method for preparing a compound having formula (II)
wherein R 1 and R 2 independently are methyl or ethyl, or R 1 and R 2 combine to form a C 5 or C 6 cycloalkyl or cycloalkenyl group; said method comprising combining R 1 R 2 CHNO 2 , glutaraldehyde and a C 6 -C 12 trialkylamine.
2. The method of claim 1 in which R 1 is methyl, R 2 is methyl or ethyl, or R 1 and R 2 combine to form a cyclohexyl group.
3. The method of claim 2 in which R 1 is methyl and R 2 is methyl or ethyl.
4. The method of claim 2 further comprising contacting the compound of formula (II) with a reducing agent capable of reducing aliphatic nitro groups to produce a compound of formula (I)
5. The method of claim 4 in which R 1 is methyl and R 2 is methyl or ethyl.
6. A method for adjusting pH in a coating composition; said method comprising adding to an aqueous coating composition having a pH below 7 a sufficient amount of a compound of formula (I) to produce a final pH from 7.5 to 9.5
wherein R 1 and R 2 independently are methyl or ethyl, or R 1 and R 2 combine to form a C 5 or C 6 cycloalkyl or cycloalkenyl group.
7. The method of claim 6 in which R 1 is methyl, R 2 is methyl or ethyl, or R 1 and R 2 combine to form a cyclohexyl group.
8. The method of claim 7 in which the aqueous coating composition is an acrylic latex comprising polymerized units of acrylic acid, methacrylic acid, or a combination thereof.
9. The method of claim 8 in which R 1 is methyl and R 2 is methyl or ethyl.