Synthesis of Acetaldehyde and Paraldehyde - Erowid
Although the mechanism is not entirely clear, the inhibition of PG synthesis plays a leading role.
Synthesis of Acetaldehyde and Paraldehyde ..
Animal experiments on the chronic toxicity of ethylbenzene have shown that high concentrations (1,000 and 100 mg/m3) may be harmful and cause functional and organic disturbances (nervous system disorders, toxic hepatitis and upper respiratory tract complaints). Concentrations as low as 10 mg/m3 may lead to catarrhal inflammation of the upper respiratory tract mucosae. Concentrations of 1 mg/m3 give rise to disorders of liver function.
There have been reports of serious intoxication in workers who had inhaled concentrated naphthalene vapours; the most common symptoms were haemolytic anaemia with Heinz bodies, hepatic and renal disorders, and optic neuritis. Prolonged absorption of naphthalene may also give rise to small punctiform opacities in the periphery of the crystalline lens, with no functional impairment. Eye contact with concentrated vapours and condensed micro-crystals may result in punctiform keratitis and even chorioretinitis.
whose mechanism of action is based on the ..
Vapours of ethylbenzene and styrene in concentrations of over 2 mg/ml may cause acute poisoning in laboratory animals; the initial symptoms are irritation of the mucous membranes of the upper respiratory tract, the eyes and mouth. These symptoms are followed by narcosis, cramps and death due to respiratory-centre paralysis. The main pathological findings are oedema of the brain and lungs, epithelial necrosis of the renal tubules, and hepatic dystrophy.
In industry acute styrene or ethylbenzene poisoning may occur as the result of a breakdown or faulty plant operation. A polymerization reaction that gets out of control is accompanied by a rapid release of heat and necessitates prompt purging the reaction vessel. Engineering controls that avoid a sudden rise of the styrene and ethylbenzene concentrations in the workplace atmosphere are essential or workers involved can be exposed to the dangerous levels with sequelae such as encephalopathy and toxic hepatitis unless they are protected by suitable respirators.
Mechanism of ActionBarbiturates ..
The blood changes manifest themselves as anaemia, poikilocytosis, anisocytosis, leukopenia (sometimes leukocytosis) with relative lymphocytosis, and in certain cases strongly pronounced thrombocytopenia. There are data on differences in individual susceptibility to xylene. No chronic intoxication has been observed in certain workers exposed for a few decades to xylene, whereas a third of the personnel working under the same conditions of exposure presented symptoms of chronic xylene poisoning and were disabled. Prolonged exposure to xylene may reduce the resistance of the organism and render it more susceptible to various kinds of pathogenic factors. Urinalysis reveals proteins, blood, urobilin and urobilinogen in the urine.
Chronic toxicity. Both styrene and ethylbenzene may also cause chronic poisoning. Prolonged exposure to styrene or ethylbenzene vapours in concentrations above permitted levels may result in functional disorders of the nervous system, irritation of the upper airways, haematological changes (in particular leukopenia and lymphocytosis) and also in hepatic and biliary tract conditions. Medical examination of workers employed for more than 5 years in polystyrene and synthetic rubber plants in which the atmospheric styrene and ethylbenzene concentrations were around 50 mg/m3 revealed cases of toxic hepatitis. Prolonged exposure to styrene concentrations of less than 50 mg/m3 caused disorders of certain liver functions (protein, pigment, glycogen). Polystyrene production workers have also been found to suffer from asthenia and nasal mucosa disorders; ovulation and menstruation disorders have also been observed.
Paraldehyde is the cyclic trimer of ..
it is used as-is in the synthesis of bromal ..
Caution forms easily paraldehyde Application Acetaldehyde may be used for the enzymatic synthesis of fatty acids
PARALDEHYDE is a hypnotic and sedative with anticonvulsant effects
Mechanism of action: Paracetamol exhibits analgesic action by peripheral blockage of pain impulse generation
It is also a building block in the synthesis of ..
The radical mechanism of biological methane synthesis by methyl-coenzyme M reductase Science
Chloral hydrate is a geminal diol with the ..
Toluene has no action on the bone marrow. Those cases that have been reported relate either to an exposure to toluene together with benzene or are not clear on this subject. In theory it is possible that toluene can give rise to a hepatotoxic attack, but this has never been proved. Certain authors have suggested the possibility of its causing an autoimmune illness similar to the Goodpasture syndrome (autoimmune glomerulonephritis).
Radical polymerization - Wikipedia
From the biological point of view, it seems that the bone marrow and blood disorders found in chronic benzene poisoning can be attributed to the conversion of benzene to benzene epoxide. It has been suggested that benzene might be oxidized to epoxide directly in bone marrow cells, such as erythroblasts. As far as the toxic mechanism is concerned, benzene metabolites seem to interfere with nucleic acids. Increased rates of chromosome aberrations have been observed both in humans and in animals exposed to benzene. Any condition likely to inhibit further metabolism of benzene epoxide and conjugation reactions, especially hepatic disorders, tends to potentiate the toxic action of benzene. These factors are of importance when considering differences in individual susceptibility to this toxic agent. Benzene is discussed in more detail elsewhere in this Encyclopaedia.
Preparation of pentaerythritol (Pentaerythrite)
The toxicity of chloronaphthalenes increases with a higher degree of chlorination. Chloracne and toxic hepatitis are the primary problem caused by exposure to this substance. The higher chlorinated naphthalenes may cause severe injury to the liver, characterized by acute yellow atrophy or by subacute necrosis. Chloronaphthalenes also have a photosensitizing effect on the skin.
Aldol Addition - Organic chemistry
Mechanism. Absorption of benzene usually occurs through the lungs and gastrointestinal tract. It tends not to be well absorbed through the skin unless exceptionally high exposures occur. A small amount of benzene is exhaled unchanged. Benzene is widely distributed throughout the body and is metabolized mainly to phenol, which is excreted in the urine after conjugation. After exposure ceases, body tissue levels decline quickly.
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