Triazine herbicides

A compound of the formula I ##STR19## wherein R.sup.1 and R.sup.2 each independently represent a hydrogen or halogen atom, or an optionally substituted C.sub.1-12 alkyl, C.sub.2-12 alkenyl, C.sub.2-12 alkynyl, C.sub.3-8 cycloalkyl, C.sub.1-12 alkoxy, C.sub.2-12 alkenyloxy, C.sub.2-12 alknyloxy, phenyloxy, C.sub.1-12 alkylthio, C.sub.2-12 alkenylthio, C.sub.2-12 alkynylthio, phenylthio or amino group, or a formyl, optionally substituted C.sub.1-12 alkylcarbonyl, cyano, carboxy, optionally substituted C.sub.1-12 alkoxycarbonyl, dialkylaminoxy, dialkyliminoxy or azido group;

• x represents an oxygen or sulphur atom or a group --SO.sub.2 --, --SO-- or --NR.sup.4 -- where R.sup.4 represents a hydrogen atom or an optionally substituted alkyl group;
• n is an integer from 1 to 4;
• Y represents a hydrogen atom or each Y independently represents a halogen atom, a hydroxy group or an optionally substituted C.sub.1-12 alkyl, C.sub.2-12 alkenyl, C.sub.2-12 alkynyl, phenyl, C.sub.1-12 alkoxy, C.sub.2-12 alkenyloxy, C.sub.2-12 alkynyloxy, phenyloxy, C.sub.1-12 alkythio, C.sub.2-12 alkenylthio C.sub.2-12 alkynylthio, phenylthio or amino group, or a formyl, optionally substituted alkylcarbonyl, cyano or nitro group, or, when n is at least 2, two groups Y may be linked to form a fused saturated carbocyclic ring;
• and
• Z represents a hydroxyalkyl, hydroxybenzyl, or mono-, di- or trialkoxyalkyl group, a group --CH.dbd.NOH, or an optionally esterified carboxyalkyl group, or a group COR.sup.3 where R.sup.3 represents a hydrogen or halogen atom, or a hydroxy group, or an optionally substituted C.sub.1-12 alkyl, phenyl, C.sub.2-12 alkenyl, C.sub.2-12 alkynyl, C.sub.1-12 alkoxy, C.sub.2-12 alkenyloxy, C.sub.2-12 alkynyloxy, cycloalkyloxy, phenyloxy, dialkylaminoxy, dialkyliminoxy, amino, C.sub.1-12 alkylthio, phenylthio, C.sub.2-12 alkenylthio or C.sub.2-12 alkynylthio group, or a carboxylic acid salt of a compound of formula I with an equivalent amount of an inorganic or organic cation,
• said optional substituents for alkyl, alkenyl, alkynyl, alkoxy, alkenylthio, alkylcarbonyl, and alkoxycarbonyl groups being independently selected from one or more of halogen, C.sub.1-12 alkoxy, hydroxy, C.sub.1-12 alkylthio, phenylthio, phenyl, alkylsulphinyl, alkylenedioxy, alkylenedithio, haloalkyl, and alkoxycarbonyl groups, thienyl groups and dialkyliminoxy, optionally substituted amino, trialkylsilyl, alkylcarbonyl, phenylcarbonyl, alkoxycarbonyl, carboxy, cyano, thiocyanate, and optionally substituted aminocarbonyl groups,
• said optional substitutents for phenyl, cycloalkyl, phenyloxy or phenylthio groups may be independently selected from one or more of halogen atoms and nitro, cyano, C.sub.1-12 alkyl, C.sub.1-12 haloalkyl, C.sub.1-12 alkoxy, C.sub.1-12 alkylthio, C.sub.1-12 alkoxycarbonyl and aralkoxycarbonyl groups,
• said optional substitutents for an amino group being independently selected from C.sub.1-12 alkyl, C.sub.1-12 alkoxy, amino, mono or dialkylamino, arylamino, alkoxyalkyl, haloalkyl, hydroxy, hydroxyalkyl, carboxyalkyl or alkylcarbonylamino, or the amino group may form part of a pyrrolidinyl or morpholino ring.