Guidelines for care & Use of Dry Solvent Stills [Example]

9. Esters
10. Ethers
11. Halogens
Nitriles can cause the same general symptoms as HCN, but the onset is apt to be slower and they
are more likely to be active as primary irritants on the skin or eye. They are also frequently
absorbed rapidly and completely through the intact skin in the same manner as the cyanides. The
halogenated compounds are also highly toxic and possess some of the same properties as HCN.
However, at low concentrations, these materials behave more like the highly irritating vesicant
gases such as phosgene and cause severe lachrymatory effect and both acute and delayed
pulmonary edema and irritation.
The action of the esters varies widely from the mildly anesthetic and irritant properties of ethyl
acetate to the very poisonous, irritant and vesicant action of methyl sulfate and the esters of
formic acid. The formic acid esters are powerful irritants, especially the chlorinated ones. They
have been used as war gases. With increase in molecular weight, the relative toxicity of the esters
increases, but because of decrease in volatility, the actual danger decreases.
The ethers are powerful narcotics acting rapidly on the central nervous system. They are also
slightly irritant and can be dangerous if inhaled in large quantities.
Chlorine is a dangerous and strong lung irritant and a concentration of one part per million for
an 8 hour exposure is the maximum allowed. This is also the lowest concentration offering a
detectable odor.
Bromine fumes are highly irritating to the eyes and both the upper and lower sections of the
respiratory tract. The maximum allowable concentration is one part per million and the least
detectable odor is in the order of 3.5 parts per million.
12. Hydrocarbons
13. Metals
Saturated aliphatic hydrocarbons are relatively harmless from the toxicological point of view.
Methane and ethane are simple asphysiants; propane and butane have, in addition, anesthetic
properties, while hydrocarbons from pentane and up are narcotic, convulsive and irritant.
Hexane and heptane are the most dangerous.
Unsaturated aliphatic hydrocarbons from ethylene to heptylene have simple asphysiant and
anesthetic properties. Acetylene may also be included in this group.
Cyclic hydrogenated hydrocarbons are more potent than the open chain hydrocarbons but are
less toxic than the aromatic hydrocarbons. Cyclohexane has about the same toxicity as hexane
but has a stronger narcotic action. They have their principal effect on the central nervous
system.
Aromatic hydrocarbons are much more poisonous than the aliphatic group. Benzene has a
destructive influence on blood cells and blood-forming organs following chronic exposure. It also
has an acute narcotic effect and may cause intoxication, unconsciousness or death in a short time
if present in high concentration. It may be carcinogenic.
Halogenated hydrocarbons as a class have the general physiological effect of anesthesia and
narcosis. Permanent damage may result to the liver and kidneys. The halogenated hydrocarbons
of the benzene group may be blood poisons.
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