Rohm and Haas Company

Morton International, Inc.

Al Zimin, Sr

Michael R Friswell

Peter A Caputo

Two or more dyes or markers, including a dye or marker having an absorbance peak in the 400 to 500 nm range and including a dye or marker having an absorbance peak in the 560 to 700 nm range are mixed together in appropriate ratios so when added to a liquid, such as a petroleum fuel, at combined levels of from 5 to 100 ppm, the colors of the dyes and/or markers cancel each other such that a &ldquo;water-white&rdquo; liquid still appears &ldquo;water-white&rdquo;.

Color canceling marking systems

A stabilized aqueous solution of a diazo compound has the formula: ##STR1## where X.sup.1 is selected from nitro and chloro, X.sup.2 is selected from nitro, chloro and hydrogen, and Y is an acid-derived anion. The solution has a pH of about 1.5 or below and a diazo concentration of about 2 wt % or less. The solution is useful as an extractant/developer for petroleum fuel markers.

Growing community of inventors

Wayne, NJ, United States of America

Al Zimin, Sr