Bengal

WATER - WATERPROOFING AND WATER/OIL REPELLENCY] (Vol 25) Rose Bengal [11121-48-5]... 

World markets for vegetable fibers have been steadily declining in recent years, mainly as a result of substitution with synthetic materials. Jute has traditionally been one of the principal bast fibers (toimage basis) sold on the world market however, the precipitous decline in jute exports by India (Fig. 2) indicate the decreasing market demand for this fiber that is vitally important to the economies of India (West Bengal), Bangladesh, and Pakistan. 

The role of rose bengal and other sensitizer dyes in the photodimerization of 2-acet5i-l,4-benzoquinone [1125-55-9] involves electron transfer but not singlet oxygen (42) (see Dyes, SENSITIZING). 

Dyes, xanthene used for eosin, fluorescein-type phthaleins, rhodamines, and rose Bengal. 

Photooxidafions are also iudustriaHy significant. A widely used treatment for removal of thiols from petroleum distillates is air iu the presence of sulfonated phthalocyanines (cobalt or vanadium complexes). Studies of this photoreaction (53) with the analogous ziuc phthalocyanine show a facile photooxidation of thiols, and the rate is enhanced further by cationic surfactants. For the perfume iudustry, rose oxide is produced iu low toimage quantifies by singlet oxygen oxidation of citroneUol (54). Rose bengal is the photosensitizer. 

Dye-Sensitized Photoisomerization. One technological appHcation of photoisomerization is in the synthesis of vitamin A. In a mixture of vitamin A acetate (all-trans stmcture) and the 11-cis isomer (23), sensitized photoisomerization of the 11-cis to the all-trans molecule occurs using zinc tetraphenylporphyrin, chlorophyU, hematoporphyrin, rose bengal, or erythrosin as sensitizers (73). Another photoisomerization is reported to be responsible for dye laser mode-locking (74). In this example, one metastable isomer of an oxadicarbocyanine dye was formed during flashlamp excitation, and it was the isomer that exhibited mode-locking characteristics. 

PVSA-SG film was used for determination of Fe(Phen) + and Zn + as ternary complex Zn +-Phen-bengal rose by spectrophotometric method. The calibration graph was linear in the concentration 5T0 -5T0 mol/lfor Fe(II) and FlO - 5T0 mol/1 for Zn(II). The film can be regenerated and reused. LG-PDMDA-SG film was shown to be perspective modificator of the PG electrode surface and used for voltammetric detection of Mo(VI) at ppb level. 

It was shown that Zn + adsorbed onto SG-PVSA composite film as Zn(Phen) complex. It can be detected spectrophotometrically after treatment with anionic dye Bengal Rose (BR). Ternary complex Zn + - Phen-BR formed on the surface under optimal conditions. SG-PVSA film was used for determination of Zn + by spectrophotometric method. The calibration graph was linear in the concentration range 2,5T0 - STO mol/l. 

The roots of Cephcelis Ipecacuanha (Brot) A. Rich constitute the Brazilian ipecacuanha of commerce and also that cultivated in the Federated Malay States, Bengal and Burma. Carthagena ipecacuanha is derived from Cephcelis acuminata Karsten collected in Colombia. Emetine, the principal alkaloid of this drug, was first obtained by Pelletier and Magendie in 1817, but was first prepared in a pure state by Paul and Cownley, who separated from commercial emetine the phenolic base, cephaeline, and later obtained a third alkaloid, psychotrine. To these Pyman added emetamine and 0-methylpsychotrine. 

Address 21-A Shakespeare Sarani Calcutta 700 017 West Bengal India... 

Several compounds that inhibit vesicular glutamate transport have been identified These include the dyes Evans Blue and Rose Bengal. In addition, the stilbene derivative 4,4 -diisothiocyanatostilbene-2,2 -disulfonic acid (DEDS), a compound commonly used as a specific inhibitor of anion channels, inhibits vesicular glutamate transport. Most known inhibitors have limited use as they are membrane impermeant, with the exception of Rose Bengal. 

Photo-induced Diels Alder reaction occurs either by direct photo activation of a diene or dienophile or by irradiation of a photosensitizer (Rose Bengal, Methylene Blue, hematoporphyrin, tetraphenylporphyrin) that interacts with diene or dienophile. These processes produce an electronically excited reagent (energy transfer) or a radical cation (electron transfer) or a radical (hydrogen abstraction) that is subsequently trapped by the other reagent. 

Bengal, Methylene Blue, haematoporphyrin and tetraphenylporphyrin and, generally, in organic solvents. Some examples are illustrated in Scheme 4.15. Peroxide products obtained from fatty acid precursors [61] or from cyclopenta-dienes [62] are of interest as pharmaceuticals or for biomedical studies others are versatile starting materials for further transformation. 

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