MCPA
Trade and Other Names: Trade or other names for MCPA or products containing it include: Agritox, Agroxone, Agrozone, Agsco MXL, Banlene, Blesal MC, Bordermaster, Cambilene, Cheyenne, Chimac Oxy, Chiptox, Class MCPA, Cornox Plus, Dakota, Ded-Weed, Empal, Envoy, Gordon's Amine, Kilsem, Legumex, Malerbane, Mayclene, MCP, Mephanac, Midox, Phenoxylene, Rhomene, Rhonox, Sanaphen-M, Shamrox, Selectyl, Tiller, U 46 M-Fluid, Vacate, Weed-Rhap, and Zhelan.
Chemical Class: phenoxy compound
Introduction: MCPA is a systemic postemergence phenoxy herbicide used to control annual and perennial weeds (including thistle and dock) in cereals, flax, rice, vines, peas, potatoes, grasslands, forestry applications, and on rights-of-way. This herbicide is very compatible with many other compounds and may be used in formulation with many other products, including bentazone, bromoxynil, 2,4-D, dicamba, fenoxaprop, MCPB, mecoprop, thifensulfuron, and tribenuron.
NOTE: As with some of the other phenoxy herbicides, MCPA is an acid, but is often formulated as a salt (e.g. dimethylamine salt) or an ester (e.g. isooctyl ester). Unless otherwise indicated, this document will refer to the acid form.
Formulation: This herbicide is very compatible with many other compounds, and may be used in formulation with many other products, including bentazone, bromoxynil, 2,4-D, dicamba, fenoxaprop, MCPB, mecoprop, thifensulfuron, and tribenuron.
Physical Properties:
Appearance: Pure MCPA occurs as colorless crystals.
Chemical Name: (4-chloro-2-methylphenoxy)acetic acid
CAS Number: 94-74-6
Molecular Weight: 200.62
Water Solubility: 825 mg/L @ 25 C (acid)
Solubility in Other Solvents: v.s. in ether, ethanol, toluene, xylene; s. in methanol
Melting Point: 118-119 C
Vapor Pressure: 0.2 mPa @ 20 C
Partition Coefficient: Not Available
Adsorption Coefficient: MPCA acid, 100; MCPA salts, 20 (estimated); MCPA ester, 1000 (estimated)