Benzofuran herbicidal aq. suspensions esp. for sugar beet - contain polycarboxylated vinyl polymer and surfactant

摘要

Herbicidal aqs. suspension contains a substituted benzofuran herbicide of formula (I): (where R1,R2,R3 independently = H or alkyl or R1 and R2 together or R2 and R3 together=alkylene; R4=hydroxy, opt. substd. alkoxy, opt. substd. alkenyloxy, opt. substd. alkynyloxy, opt. substd. aryloxy, alkylthio, NR6R7, -OOCR13, -OSO2R14 or -OOR15 or R3 and R4 together = O or =N-R16. R6, R7 = opt. substd. alkyl or together with the N atom form an opt. substd. heterocyclic; R13 = opt. substd. alkyl, opt. substd. alkenyl, opt. substd. alkynyl, opt. substd. aryl, mono- or dialkylamino, opt. substd-alkoxy, opt. substd. aryloxy, opt. substd. arylamino, opt. substd. alkenyloxy or opt. substd. alkynyloxy; R14= opt. substd. alkyl or opt. substd. aryl; R15= alkyl, alkenyl or alkynyl; R16 = alkyl or cycloalkyl; R5= R8CO-, R9SO2-, R9-SO-, R31R32NSO2; R8 = halogenated alkyl; R9 = opt. substd. alkyl or opt. substd. aryl; R31, R32 independently = H or opt. substd. alkyl and R10, R11, R12 independently = H, alkyl, halo, cyano, acyl or alkoxy). (I) has m.pt. >=50 degrees C and a water solubility >=0.1% at 25 degrees C. In addn. to water the compsn. also contains a polycarboxylated vinyl polymer as suspension agent, a surface activeaagent having a reversible thickening temp. of 45 degrees C or above and, when the surface active agent is not a sequenced copolymer of ethyleneoxide and propylene oxide, a deflocculating agent. Esp. useful for control of weeds in sugar beet but may also be used to control weeds in sunflowers, tobacco, pastures, crucifers etc. Usually 0.5-8kg/hectare (pref. 1-4 kg/hectare) of (I) are applied, after sowing. The suspension may be used at the post-emergent stage but is pref. used pre-emergence. The pref. cpd. (I) is 2-ethoxy-2,3-dihydro-3,3-dimethyl-benzofuran-5-yl methanesulphonate (ethofumesate).