Phenol: Highly Toxic

Phosphonothioate Esters of Phenols. Phosphonates with a single P—C bond are highly toxic and persistent iasecticides but have not been used extensively because some compounds produce delayed neuropathy leading to irreversible paralysis ia higher animals, including humans. Such compounds specifically inhibit an enzyme, neurotoxic esterase, that is responsible for the growth and maintenance of long nerve axons (31,32). 

Phenol. Phenol monomer is highly toxic and absorption by the skin can cause severe blistering. Large quantities can cause paralysis of the central nervous system and death. Ingestion of minor amounts may damage kidneys, Hver, and pancreas. Inhalation can cause headaches, dizziness, vomiting, and heart failure. The threshold limit value (TLV) for phenol is 5 ppm. The health and environmental risks of phenol and alkylated phenols, such as cresols and butylphenols, have been reviewed (66). 

Trimethylsilyl cyanide. This reagent readily silylates alcohols, phenols, and carboxylic acids, and more slowly, thiols and amines. Amides and related compounds do not react with this reagent. The reagent has the advantage that a volatile gas (HCN is highly toxic) is the only byproduct. 

Metafor 3- Mononitrophenol Monoclinic prisms from eth or dil HC1 mp 97° bp 194° at 70mm, decomps when distd at ordinary pressure d 1.485g/cc at 20°, 1.2797 at 100°. Does not volatilize with steam cannot be prepd by the nitration of phenol. Can be obtained by boiling diazotized m-nitroaniline with w and sulfuric acid (Ref 3). SI sol in w, sol in ale. Highly toxic by ingestion and inhalation Refs 1) Beil 6, 222-24, (116), [212-14]... 

Since 1950 many in the chemical industry have been keenly aware of the possibilities of highly toxic 2,3,7,8-tetrachlorodibenzo-p-dioxin forming in the manufacture of 2,4,5-trichlorophenol. This phenol is made by treating 1,2,4,5-tetrachlorobenzene with strong caustic at high temperatures for several hours. Manufacturing procedures which do not carefully control temperature and alkalinity increase the probability of dioxin formation. 

M-NHC catalysts in this area. Metal catalysed carbonylation also provides an alternative synthetic ronte to the prodnction of materials that traditionally reqnire highly toxic precnrsors, like phosgene. This section discnsses carbonylation of aryl hahdes, oxidative carbonylation of phenolic and amino componnds, carbonylation of aryl diazoninm ions, alcohol carbonylation, carbonylative amidation, and copolymerisation of ethylene and CO. 

Specific effluents have also been subjected to WRF-mediated remediation studies. Decolourization, dechlorination and detoxification of highly toxic bleach plant effluents derived from the pulp and paper industry have been reported [26-28], while degradation and decolourization of synthetic dyes due to the non-specificity of the LMEs have been widely documented [29, 30], Likewise, treatment of the acidic, phenolic-rich olive oil mill wastewater has shown COD reduction, decolourization and dephenolization [31-34],... 

At the Sn02 anode only a very small amount of highly toxic intermediates (hydroquinone, catechol, benzoquinone) is formed. These intermediates are formed in large amounts on the Pt anode probably by chemical reaction of adsorbed hydroxyl radicals with phenol. 

A hydrolysis step is involved in the pulp industry in order to concentrate the cellulose from wood. This uses large-scale processes whereby a liquid fraction, the lignocellulose, is formed as a by-product in the process, and contains high levels of phenolic components and their derivatives. These compounds also constitute an environmental problem due to their possible introduction into rivers, lakes, and/or seas. Chlorophenols from the cellulose bleaching process have traditionally attracted most of the interest in the analysis of industrial waste because of their high toxicity. 

Phenols and related compounds are highly toxic to humans and aquatic organisms, thus becoming a cause for serious concern in the environment when they enter the food chain as water pollutants. Even at very low levels (i.e., <1 ppb), phenols affect the taste and odor of water and fish [253]. New environmental regulations introduced throughout the world place greater emphasis on treatment of this industrial waste. This fact has been realized by the pulp in-... 

Phenol was mutagenic to Escherichia coli B/Sd-4 at highly toxic doses only (survival... 

Phenolic oxidation by PPO and POD in B-deficient leaves leads to the production of quinones. These compounds are known for their high toxicity, and for being responsible for the production of oxygenated radicals such as H2O2 and O2. The accumulation of quinones in plants that act as indicators of the deficiency has been considered as the prime cause of cell damage and of growth reduction [127]. 

Phenols are highly toxic. They are strongly corrosive to the skin and the mucuous membranes. 

Reductive dehalogenation of chlorinated phenols to phenol, cyclohexanol and other chlorine-free compounds takes place rapidly with hydrogen gas and Pd/C in an aqueous system or under solvent-free conditions. Thus, pentachloro phenol was able to be completely dechlorinated within 20 min (Scheme 4.45). This methodology enables a facile route for rapid and complete detoxification of highly toxic polychlorinated aromatic hydrocarbons and environmental remediation71,72. 

A study of the soil of a Douglas fir forest in The Netherlands spiked with 37CI -chloride demonstrated that chlorinated phenols, dibenzo-p-dioxins, and dibenzo-furans are produced naturally in the humic soil layer probably via chloroperoxidase chemistry (Scheme 3.5) (1712). Twenty polychlorinated dioxins and furans were found to be produced naturally in this study, including the highly toxic 2,3,7,8-tetra- (2246), 1,2,3,7,8-penta- (2247), and 1,2,3,7,8,9-hexachlorodibenzo-p-dioxin (2248). The major congeners found are 4-chloro- (2249), 1,7-dichloro-... 

---