Monuron, effect

Dimethylamine was shown to have a strong accelerating effect on the cure of a BADGE/ DICY mixture at 116 °C and it was also found that Monuron undergoes considerable reaction with the resin at 90 °C. 

Sugarcane Sower initiation is dependent on day length, temperature, age, moisture, and variety, and can be prevented by chemical applications at, or very close to, the date of floral initiation. The effective chemicals have been of two types (a) photosynthetic inhibitors, such as 3-(p-chlorophenyl)-1,1-dimethylurea (monuron), or (b) leaf-burning, contact chemicals. The very effective bipyridylium herbicides 6,7-dihydrodipyrido[l,2-a 2, r-c]pyrazidinium dibromide (diquat) and 1, l -dimethyl-4,4 -bipyridinium bis (methyl sulfate) (paraquat) combine the two properties, although the... 

Many other compounds have been included in studies on sucrose response. Most of these have been herbicides or enzyme poisons. None of the common herbicides had any positive effect on sucrose at rates up to that causing severe foliar injury. Earlier reports of response from 2-(2,4,5-trichlorophenoxy)propionic acid and 2,2-dichloropropionic acid could not be substantiated in British Guiana and Queensland. 27 Some compounds, such as 3-(p-chlorophenyl)-l,l-dimethylurea (monuron), (2,4-dichloro-phenoxy) acetic acid in soil, ethylenediaminetetraacetic acid, and leaf desiccants decreased sucrose and juice solids content. 20 Field trials with several chemicals in Trinidad showed enhanced sucrose at 14 to 28 days before harvest resulting from the application of 8 and 12 lb. (per acre) of... 

Pickett et al. (1992) reported that California citrus growers depend on herbicides for weed control. Simazine was rated as the most important herbicide used in citrus production. Abdel-Rehman et al (1994) reported that control of annual broadleaf weeds was most effective with simazine plus fluazifop and least effective with fhiazifop alone. Application of diuron or atrazine once at 1-4kg a.i./ha or twice at 1 + 1, 1 + 2 or 2 + 2kg a.i./ha, significantly reduced grasses and broadleaf weeds. Broadleaf weeds were controlled by 2-4kg a.i./ha of diuron and 2 + 2kg a.i./ ha of simazine at the 60-day sampling period (Singh et al, 1987). Perez (1976) reported that fluometuron, diuron, monuron, and simazine, all at 4.8kg a.i./ha, and bromacil at 4kg a.i./ha controlled weeds without injury to citrus on latosols, while simazine and diuron at 4.8 kg a.i./ha or bromacil at 4kg a.i./ha caused no injury to grapefruit after two applications on sandy soil. 

The acute oral lDjq of monuron for rats is 3400 mg/kg, that of diuron 3600 mg/kg. The no-effect levels for rats and dogs are 250 and 500 ppm, respectively. Monuron is nontoxic to bees, diuron mildly toxic (Beran, 1970). 

Cooke (1955) reported first that the sugar content of plants treated with monuron greatly decreased, and attributed this finding to a correlation of the phytotoxic effect of monuron with photosynthesis. 

Figure 2. The effect of a 10 M solution of ioxynil (A) or monuron (B) on the chlorophyll content of flax cotyledons incubated in sealed conical flasks containing air ( ) or argon (O) with light of 30 Wm (IS).

Figure 3. The effect of 10 M monuron on pigment content and ethane generation of flax cotyledons incubated at 30 Wm. Pigment levels are expressed as a percentage of the levels at 0 h. Key carotenes, xanthophylls, A/ chlorophyll, B, and ethane generation, O ( %).

Figure 6. The effect of monuron (10 MJ on the chlorophyll level of paraquat-treated (10 M) cotyledons under light of 5.25 Wm. Key paraquat, O and paraquat plus monuron,...

The effect of monuron (10 M) on the ability of paraquat to promote the formation of nitrite from hydroxylamine in isolated chloroplasts. For further details see legend to Figure 7, from Youngman jet al. (32)... 

Nonlinear isotherms have been reported particularly at low Cg values (Fig. 3.10a). The sorption of both dibromoethane (EDB) and the herbicide diuron (DUN) on a peat soil (49.3%OC) both show this response, which is more pronounced with the latter. A similar type of response is also observed in soils of lower organic carbon content. A competitive effect is also demonstrated with trichloroethylene and phenol suppressing the sorption of EDB and EDB (at a sufficient concentration), monuron and dichlorophenol affecting the sorption of diuron. The... 

The bipyridyl free radicals are not a direct cause of death, but just a stage in a rapid cycle of reduction and re-oxidation. In the course of this cycle much hydrogen peroxide is formed, and some superoxide free radical which is considered to be the true toxic agent (Fridovich, 1975). When monuron (see above) is used to inhibit photosynthesis, diquat loses most of its effect. Although paraquat is completely safe in normal usage, large oral doses cause fibrosis of the lungs, and death may follow. For a book on bipyridylium herbicides, see Summers (1980). 

Substituted ureas can be used for promoting a synergistic effect when curing epoxy resins with dicy. Earlier, 3-(p-chlorophenyl)-l,l-dimethylurea (Monuron made by DuPont) was popular [22,23], but it has now been withdrawn due to health hazards. 

Clamydomonas sp, Chlorella sp, and Chlorella NMI were found by Pillay and Tchan (1972) to be more sensitive than Chlorococcum, Nostoc, or Anabaena to monuron, diuron, and neburon. At very low concentrations (0.001 to 0.01 ppm) a stimulatory effect on Chlamydomonas and the two Chlorella species was observed, while at 0.1 to one ppm, the herbicides became strongly inhibitory. Stimulation by low concentrations of herbicides is well-established (Atkins 1965, Pillay 1967). 

Apart from hardener, some adhesives in this category also contain an additional activator (e.g., catalyst such as monurone - also used as cross-linking agent). With that, a faster rate of reaction can be achieved, which effectively shortens the duration needed for the adhesion process or lowers the activation temperature. However, this also leads to reduced storage stability of the adhesive. 

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