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NITRO DERIVATIVES OF PHENOL^419

the head, accelerated pulse (100-130), and respiration, a rise in temperature to

39-40°C, and moreover, in severe cases, blue mucous membranes, and spasms.

Death, as post mortem examinations have indicated, is usually caused by pneumonia

and meningitis. In many cases chronic poisoning may manifest itself by cataracts

of the eye lenses, and eczema in people with sensitive skin. Inflammation of the

lymphatic glands and degeneration of nails can often be observed.

Martin [32] found that dinitrophenol undergoes in the body a partial reduction

either to 2-amino-4-nitrophenol or to 4-amino-2-nitrophenol and 2,4-diamino-

phenol. Part of the compound is excreted unchanged in the urine.

During the 1914-1918 war, in France, where dinitrophenol was manufactured

in large quantities for explosive compositions, cases of poisoning among the workers,

including fatal cases, were frequent, e.g. within 3 months 277 fatal cases occurred

in a factory with a relatively large scale of production. Experience has shown that

most of the cases are caused by impure dinitrophenol. The reason for this is, however,

not clear since the impurities commonly present in the product are less poisonous

than 2,4-dinitrophenol itself.

Workers in the dinitrophenol plant should be protected in the usual way (i.e.

gloves, respirators, change of clothes, bath, etc.). Selection of workers handling

dinitrophenol is also recommended since it has been shown that a great many

people are resistant to its toxic effects, Selection is based on 15 days’ medical obser-

vation of each new worker in the dinitrophenol plant, in particular in the analysis

of the urine every other day. A test for the presence of aminonitrophenols is partic-

ularly importance. Usually Derrien’s reaction [33] is used. According to Lazarev

[31], the reaction comprises acidification of the urine with 10% sulphuric acid and

diazotization with sodium nitrite, followed by shaking up the prepared solution

with an ammoniacal solution of β− naphthol. If a red colour appears it indicates

the presence of 4-amino-2-nitrophenol in the urine, while a violet shade is evi-

dence for the presence of 2-amino-4-nitrophenol.

If Derrien’s test is positive, the worker should be examined every day. If after

5-6 days the reaction is still positive, the worker must be barred from handling

dinitrophenol. If the test is negative for 15 days or becomes negative by the end

of this period, the worker may carry on with his job. Medical examination should

be repeated from time to time.

In the U.S.S.R. industrial hygiene in dinitrophenol plants is determined by

NKT regulation No. 211, dated 16. June 1930 and also by the U.S.S.R. Ministry

of Health, Instruction No. 443, dated 17. June 1949. The regulations apply

chiefly to the safe handling of dinitrophenol when used as a material for impreg-

nating railway sleepers.

PRINCIPLES OF PREPARATION OF NITROPHENOLS

There are several methods of nitrophenol preparation:

(1) nitration of phenols;

(2) hydrolysis of chloronitro derivatives of aromatic compounds;