Light decomposition

Ethylene Dibromide. Technical material was washed three times with concentrated sulfuric acid, rinsed with water, and dried over calcium chloride. It was then distilled through 1 foot of glass beads. The fraction boiling between 130.2° and 131.2° C. was used. Every third day an aqueous solution was prepared by weighing approximately 0.5000 gram of ethylene dibromide into 2000.0 grams of water. It was stored in a dark bottle to minimize light decomposition. 

Smith, G.N. 1968. Ultraviolet light decomposition studies with Dursban and 3,5,6-trichloro-2-pyridinol. Jour. Econ. Entomol. 61 793-799. 

Solutions of ferrocene in halogenated solvents at room temperature are reported to be stable in the dark, but upon exposure to light decomposition occurs at a relatively rapid, quite noticeable rate. Typically, a brown sludge is formed as the decomposition proceeds. 

Vat dyestuff selection some vat dyestuffs are called fibre protectors, others are fibre damagers. The fibre protectors mostly contain nitrogen atoms in their chromophores. These vat dyestuffs have good light fasmess and compensate for the influence of the damagers. The latter and/or their light decomposition products catalyse the fibre damage by photolysis. 

Recrystallization from pentane gave attractive yellow crystals. The structure of 2 could be determined by X-ray diffraction analysis (Figure 2). The NMR spectroscopic results were consistent with the assigned structure (Table 1). The IR spectrum shows three v(CO absorptions at 1965, 1991 and 2044 cm. This behavior is typical for metal carbonylates of the type c/s-L2M(CO)3 Compound 2 is more stable than the previosly described (ri -C5H5)M(CO)3SiMe2SiMe2Br (M=W, Mo) [5], Complex 2 decomposes thermally below 150°C and is stable against light. Decomposition under the influence of donor solvents was not observed. 

Poly-rert-butylphenol disulfide Yellow to light Decomposition temperature > 200° C Vulcanizing... 

Stable under normal storage conditions. Hydrolyzed by strong acids and alkalis. Stable to light. Decomposition temperature >200°C. Main loss from soil via microbial degradation. ty2 (soil heavy clay) 10 to 12 weeks, (soil loam) 8 to 10 weeks... 

Decomposes on standing for a long time, especially in light. Decomposition is recognized by the xmpleasant odor. Burns with a blue flame to CO3 and SO3 ignition point 236°C. 

The above is a thetmal process. Free radicals can also be generated with the aid of UV light. This, for instance, was done with a UV light decomposition of benzoin methyl ether in the presence of an oxidizing salt ... 

What happens to the final radical is uncertain. High conversions were reported in polymerizations of n-butyl vinyl ether in the presence of azobisisobutyronitrile (as a source of radicals) with ip - tolyl)2—I PFe at 50°C [55]. The above is an illustration of a thermal process [12]. Free radicals can also be generated with the aid of UV light. This, for instance, was done with a UV light decomposition of benzoin methyl ether in the presence of an oxidizing salt [56] ... 

Also, it was found that hexaarylbisimidazole will initiate polymerizations as a result of irradiation with visible light. The same is true of bisacylphosphine oxde. Other eompounds are ketocoumarins that are efficient photoinitiators for acrylic and methacrylic monomers in the presences of amines, phenoxy acetic acid, and alkoxy pyridinium salts. It was also shown that free-radical initiation is possible through visible light decomposition of ferrocenium salts in a three component composition, combined with either a hydroperoxide or a epoxide, and a third ingredient, a dicyanobutadiene derivative ... 

Relatively stable in aqueous acidic media in the presence of stabilizers such as urea derivatives, sulphamide, oxamide, DMF, caprolactam, 7V-methyl-2-pyrrolidone, dimethylhydantoin, succinimide (Burk Reineke, 1979) unstable to UV light, decomposition in media with pH values above 7 increasing with increase in pH and temperature... 

Polyester resins can be cross-linked by a free-radical initiator, usually an organic peroxide. Free radicals may be formed by thermal decomposition of an initiator such as erf-butyl perbenzoate or benzoyl peroxide, by ultraviolet (UV) or visible light decomposition, or by chemical decomposition in ambient temperature applications utilizing activators such as dimethylaniline. Inhibitors such as hydroquinone consume free radicals initially and reaction does not proceed until the inhibitor system is completely consumed. After an induction period the free... 

Nitric acid is subject to thermal or light decomposition with increasing concentration and this may give rise to some non-negligible variations in the vapor pressure above the liquid because the nitrogen oxides produced dissolve partly or completely in the acid. 

---