Abstract: The invention relates to novel aromatic acids, especially to compounds of formula ##STR1## wherein R.sub.1 is lower alkyl, R.sub.2 is lower alkyl, R.sub.3 is hydrogen, carboxy or sulfo, R.sub.4 is carboxy or sulfo, G is an unsubstituted or substituted 1,4-phenylene group or an unsubstituted or substituted 1,4-naphthylene group, and wherein either R.sub.5 and R.sub.6 together are an additional bond and L is an oxygen or sulfur atom or wherein R.sub.5 is hydrogen, R.sub.6 is halomethyl and L is an oxygen atom, and salts thereof, to the use of compounds I and their salts, to a process for the preparation of compounds I and their salts, to starting materials used in that preparation process, and salts thereof, to a process for the preparation of those starting materials and their salts, to a device in which the compounds I and their salts are used, and to a process in which that device is used.

Abstract: The invention relates to novel aromatic acids, especially to compounds of formula ##STR1## wherein R.sub.1 is lower alkyl, R.sub.2 is lower alkyl, R.sub.3 is hydrogen, carboxy or sulfo, R.sub.4 is carboxy or sulfo, G is an unsubstituted or substituted 1,4-phenylene group or an unsubstituted or substituted 1,4-naphthylene group, and wherein either R.sub.5 and R.sub.6 together are an additional bond and L is an oxygen or sulfur atom or wherein R.sub.5 is hydrogen, R.sub.6 is halomethyl and L is an oxygen atom, and salts thereof, to the use of compounds I and their salts, to a process for the preparation of compounds I and their salts, to starting materials used in that preparation process, and salts thereof, to a process for the preparation of those starting materials and their salts, to a device in which the compounds I and their salts are used, and to a process in which that device is used.

Abstract: The invention relates to novel aromatic acids, especially to compounds of formula ##STR1## wherein R.sub.1 is lower alkyl, R.sub.2 is lower alkyl, R.sub.3 is hydrogen, carboxy or sulfo, R.sub.4 is carboxy or sulfo, G is an unsubstituted or substituted 1,4-phenylene group or an unsubstituted or substituted 1,4-naphthylene group, and wherein either R.sub.5 and R.sub.6 together are an additional bond and L is an oxygen or sulfur atom or wherein R.sub.5 is hydrogen, R.sub.6 is halomethyl and L is an oxygen atom, and salts thereof, to the use of compounds I and their salts, to a process for the preparation of compounds I and their salts, to starting materials used in that preparation process, and salts thereof, to a process for the preparation of those starting materials and their salts, to a device in which the compounds I and their salts are used, and to a process in which that device is used.

Abstract: The invention relates to azo compounds, especially to compounds of formula ##STR1## wherein R.sub.1 is lower alkyl, R.sub.2 is lower alkyl, R.sub.3 is hydrogen, carboxy or sulfo, R.sub.4 is carboxy or sulfo, G is an unsubstituted or substituted 1,4-phenylene group or an unsubstituted or substituted 1,4-naphthylene group, and wherein either R.sub.5 and R.sub.6 together are an additional bond and L is an oxygen or sulfur atom or wherein R.sub.5 is hydrogen, R.sub.6 is halomethyl and L is an oxygen atom, and salts thereof, to the use of compounds I and their salts, to a process for the preparation of compounds I and their salts, to starting materials used in that preparation process, and salts thereof, to a process for the preparation of those starting materials and their salts, to a device in which the compounds I and their salts are used, and to a process in which that device is used.