Dangerous reactions effects

Zone-1 - Usually no reaction Zone-2 - Usually no dangerous physiological effect... 

Professor Martel s book addresses specifically some of the more technical eispects of the risk assessment process, mainly in the areas of hazard identification, and of the consequence/effect analysis elements, of the overall analysis whilst where appropriate setting these aspects in the wider context. The book brings together a substantial corpus of information, drawn from a number of sources, about the toxic, flammable and explosive properties and effect (ie harm) characteristics of a wide range of chemical substances likely to be found in industry eind in the laboratory, and also addresses a spectrum of dangerous reactions of, or between, such substances which may be encountered. This approach follows the classical methodology and procedures of hazard identification, analysing material properties eind... 

Tin disulphide has the same dangerous reactions as sulphides, for which sulphide anion is very sensitive to the effect of oxidants. So the effect of chloric acid and chlorates gives rise respectively to violent detonations and the formation of spectacular showers of sparks. Dichlorine oxide detonates, but this is to be expected. 

Phenols have two structural features, the hydroxyl function and the aromatic ring, for which the dangerous reactions are analysed on p.250. There follows an analysis of the effects of each of these features on the other and their consequences in terms of risk. 

Finaiiy, carbon chains that have an unsaturated bond, an aromatic ring or another group, can cause dangerous reactions which involve these structural elements or groups. In this case, the simultaneous presence of these structural parameters can boost their reactivity due to the electronic effects that they exert on each other. 

As usual the dangerous reaction has most effect on the compounds which are most often handled, ie chlorinated derivatives. If the operating methods are not well executed, this will be a determining factor in an accident. 

The interaction between nitromethane, the etherate of boron trifluoride and silver oxide gives rise to an extremely dangerous reaction. However, it is difficult to interpret it. Can it be explained by the unstable property of silver tetrafluoroborate or the destabilising effect of boron trifluoride on nitromethane ... 

There is also the haloform reaction (effect of a haloform on a ketone in a basic medium), already described with halogen derivatives on p.272 (the danger is more related to the interaction of the polyhalogen derivative with the base, according to the author). A large number of accidents involved the ketone as much as butanone. The accident below illustrates the danger of this reaction ... 

The effect of nitric acid on dimethyl sulphide in the presence of dioxan gives rise to a detonation, even at liquid nitrogen temperatures. There is no factor in this description that can prove whether the accident is related to sulphide or dioxan, which probably gives rise to dangerous reactions with nitric acid. 

Problems associated with these drugs include troublesome and potentially dangerous side effects, including extrapyramidal reactions, hypersensitivity reactions with possible liver dysfunction, marrow aplasia, and excessive sedation. 

Reactivity A substance s susceptibility to undergoing a chemical reaction or change that may result in dangerous side effects, such as explosion, burning, and corrosive or toxic emissions. 

The control of dangerous reactions to components in foods is not as widely conducted as is the monitoring of side effects caused by pharmaceuticals. This problem results mainly from the complexity of food matrices, and from the limited possibilities for attributing specific effects to particular food components. 

Unstable chemicals are subject to spontaneous reactions. Situations where unstable chemicals may be present include the catalytic effect of containers, materials stored in the same area with the chemical that could initiate a dangerous reaction, presence of inhibitors, and effects of sunlight or temperature change. Examples include acetaldehyde, ethylene oxide, hydrogen cyanide, nitromethane, organic peroxides, styrene, and vinyl chloride. 

Frequently occurring adverse effects are gastrointestinal complaints and dose related CNS effects including fatigue, sedation, ataxia, dysarthria and other symptoms of incoordination. Rare but potentially dangerous reactions are bone marrow depression and pancreatitis. The risk of serious and potentially fatal hepatotoxicity is greater in children under 2 years. 

Adverse effects occur in 3-12% in the form of rash, fever, urticaria, vasculitis, arthralgia, a lupuslike reaction, cholestatic jaundice, hepatitis, lym-phadenopathy and polyserositis but the most dangerous adverse effect is agranulocytosis (it occurs only in 0.3-0.6%). The reaction is readily reversible when the drug is discontinued. Cross-sensitivity between propylthiouracil and methimazole is about 50%, therefore switching drugs in patients with severe reactions is not recommended. 

Anyone prescribed an antidepressant should not take other medications without consulting with a physician. This warning of possible negative effects can also occur with over-the-counter-drugs that patients take themselves. A prescription for an antidepressant should include a list of foods to avoid, because some antidepressants can have dangerous reactions with foods. 

CONSENSUS REPORTS lARC Cancer Review Animal Sufficient Evidence IMEMDT 5,47,74 IMEMDT 20,195,79. SAFETY PROFILE Confirmed carcinogen with experimental tumorigenic and neoplastigenic data. Poison by inhalation and ingestion. Human systemic effects by an unspecified route convulsions. Potentially dangerous reaction with DMF in presence of Fe, also CCU. When heated to decomposition it emits highly toxic fumes of cr, HCl, and phosgene. See also BENZENE HEXACHLORIDE and other benzenehexachloride entries. 

The enantiomeric purity of our synthetic (S)-141, however, was only 59% ee. Acid treatments (H I and 1 141) in the course of the synthesis caused partial racemization due to retro-aldol/aldol and/or retro-Michael/Michael reactions. Unfortunately, milder methods of deprotection such as hot dilute acetic acid or trifluoroacetic acid in dichloromethane were not effective enough to give 141 in appreciable yield. In enantioselective syntheses, retro-aldol/aldol and/or retro-Michael/Michael processes are most dangerous reactions to cause partial racemization. 

For a cholinergic neuron to receive another impulse, acetylcholine must be released from the receptor to which it has bound. This will only happen if the concentration of acetylcholine in the synaptic cleft is very low. Low synaptic concentrations of acetylcholine can be maintained via a hydrolysis reaction catalyzed by the enzyme acetylcholinesterase. This enzyme hydrolyzes acetylcholine into acetic acid and choline. If acetylcholinesterase activity is inhibited, the synaptic concentration of acetylcholine will remain higher than normal. If this inhibition is irreversible, as in the case of exposure to many nerve gases and some pesticides, sweating, bronchial constriction, convulsions, paralysis, and possibly death can occur. Although irreversible inhibition is dangerous, beneficial effects may be derived from transient (reversible) inhibition. Drugs that inhibit acetylcholinesterase in a... 

The incidence of adverse reactions to rifamycins and especially rifampicin is low and the side effects reported are said to be mild and transient, provided the drug is administered daily. By contrast, intermittent administration or readministration after longer periods carry the risk of unpleasant, sometimes potentially dangerous reactions. It is considered possible that some of these phenomena are due to underlying immunologic mechanisms. 

Precaution Combustible liq. avoid contact with air or oxygen (explosion danger, adverse effect on subsequent reactions)... 

Toxicology LC50 8050 ppm harmful low acute inhalation toxicity si. toxic by ingestion irritating to eyes and skin potential anesthesia hazard in enclosed space TSCA listed Precaution Flamm. liq. dangerous fire risk avoid contact with air or oxygen (explosion danger, adverse effect on subsequent reactions)... 

Fluorine, the most reactive element known, is a dangerous material but may be handled safely using proper precautions. In any situation where an operator may come into contact with low pressure fluorine, safety glasses, a neoprene coat, boots, and clean neoprene gloves should be worn to afford overall body protection. This protection is effective against both fluorine and the hydrofluoric acid which may form from reaction of moisture in the air. 

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