Method for marking liquid hydrocarbons and other fuels and oils
A method for marking a petroleum hydrocarbon, biodiesel fuel or ethanol fuel by adding to the petroleum hydrocarbon, biodiesel fuel or ethanol fuel at least one compound having formula (I) wherein R 1 and R 2 independently represent at least one substituent selected from the group consisting of hydrogen, C 1 -C 12 alkyl, C 1 -C 12 alkoxy and nitro; and R 3 and R 4 independently represent hydrogen, methyl or ethyl.
1. A method for marking a petroleum hydrocarbon, biodiesel fuel or ethanol fuel; said method comprising adding to said petroleum hydrocarbon, biodiesel fuel or ethanol fuel at least one compound having formula (I)
wherein R 1 and R 2 independently represent at least one substituent selected from the group consisting of hydrogen, C 1 -C 12 alkyl, C 1 -C 12 alkoxy and nitro; and R 3 and R 4 independently represent hydrogen, methyl or ethyl.
2. The method of claim 1 in which R 4 is hydrogen and R 3 is methyl or hydrogen.
3. The method of claim 2 in which R 1 and R 2 independently represent at least one substituent selected from the group consisting of hydrogen, C 1 -C 4 alkyl, C 1 -C 4 alkoxy and nitro.
4. The method of claim 3 in which R 3 is hydrogen.
5. The method of claim 4 in which each compound of formula (I) is present at a level from 0.05 ppm to 20 ppm.
6. The method of claim 5 in which at least one of R 1 and R 2 represents a substituent other than hydrogen.
7. The method of claim 6 in which R 1 and R 2 independently represent at least one substituent selected from the group consisting of hydrogen, C 1 -C 2 alkyl, C 1 -C 2 alkoxy and nitro.
8. The method of claim 7 in which each compound of formula (I) is present at a level from 0.1 ppm to 10 ppm.
9. A method for identifying a petroleum hydrocarbon, biodiesel fuel or ethanol fuel marked with at least one compound having formula (I)
wherein R 1 and R 2 independently represent at least one substituent selected from the group consisting of hydrogen, C 1 -C 12 alkyl, C 1 -C 12 alkoxy and nitro; and R 3 and R 4 independently represent hydrogen, methyl or ethyl; wherein each compound of formula (I) is present at a level from 0.05 ppm to 20 ppm; said method comprising separating each compound of formula (I) using a chromatographic method and identifying each compound of formula (I) by mass spectral analysis.
10. The method of claim 9 in which R 3 and R 4 are hydrogen, at least one of R 1 and R 2 represents a substituent other than hydrogen and R 1 and R 2 independently represent at least one substituent selected from the group consisting of hydrogen, C 1 -C 4 alkyl, C 1 -C 4 alkoxy and nitro.