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arID W. FASSETT                                                                    CYANIDES AND NITRILES                     2033

         eH5CHCNBr (Bromobenzylnitrile)                            4.  Physiological Response
                                                                       Since the introduction of this material in the manufacture of synthetic foams,
                                                                   there have been a number of reports of severe pulmonary effects in man, usually
                                                                   beginning after a latent period with repeated exposures and characterized by an
                                                                   acute asthmalike reaction.76 Direct pulmonary irritant effects are noted in ani­
                                                                   mals,77 although the specific picture of a sensitization-type asthma has not been
                                                                   reproduced in animals. Skin sensitization in animals has been demonstrated. This
                                                                   does not appear to have been a major problem in humans.
         5 (20°C.)                                                     Merewether78 points out that the isocyanates are very reactive substances and
                                                                   are known to react with various groupings in proteins and thus should be capable
                                                                   of forming antigens. The reaction is probably with free amino groups. In the case
          ily potent lachrymator. The CN group is prob-            of phenyl isocyanate, the reaction leads to the formation of a phenylhydantoic
          ■CN.4 Like some other potent lachrymators, it            acid.79 There seems little doubt that the pulmonary reaction is at least partly
          lion with SH groups.75                                   based on some type of delayed or sensitization-type reaction.
          cal effects of various levels in air as follows:             Because the pulmonary effects can be produced in man at very low levels in
          mg./cu. meter                                            air, TDI should only be used in areas with adequate general and local ventilation
           0.15 mg./cu. meter                              <       or with air-supplied respirator equipment. Skin contact should be avoided. Per­
          : mg./cu. meter (10 min.)                                sons with chronic respiratory disease or respiratory allergies should not be exposed.
          ng./cu. meter (30 min.); 3500.0 mg./cu. meter                Other isocyanates may have irritant properties on the eyes or respiratory
          *         \                  i ■¥,               I       tract.
                                                           i
                                                                   5.  Threshold Limit Value
           CH3C6H3(NCO)2 (Tolylene
                                                                      0.02 p.p.m. (0.14 mg./cu. meter).24 May not protect persons having a previous
                                                                  specific sensitization.

                                                                  6.  Odor Threshold
           jolyurethane foams, foam-type insulation, etc.
                                                                      0.4 p.p.m. in about half of subjects.
                                                                   SODIUM DICYANAMIDE, NaN(CN)2

                                                                   1« Uses and Industrial Exposures
                                                                      Sodium dicyanamide is used as a chemical intermediate. It is said to repel
                                                                  moths and to have some insecticidal properties.
             p                                                    2. Physical and Chemical Properties
           ‘one, ethyl acetate, toluene, and kerosene                 Physical state: colorless crystals
            11 mg./liter o 140.5 p.p.m.                               Molecular weight: 89.04
                                                                      Melting point: 315°C. (decomposes)
                                                                      Soluble in water: 26.5 g. per 100 g. of water at 30°C.; soluble in methanol:
            Ie.76                                                 4.2 g. per 100 g. of methanol at 30°C.
            )oxia No. 2, Cambridge Univ, Press, Mass., 1948.          17 J. A. Zapp, Jr., Arch. Ind. Health, 15, 324 (1957).
            ; Guide, Toluene 2,4-Diisocyanate, Am. Ind. IIyQ-         78 E. R. A. Merewether, Industrial Medicine and Hygiene, Vol. Ill, Butterworth, London,
                                                                  1956.    '
                                                                      78 J. S. Fruton, General Biochemistry, 2nd ed., Wiley, New York, 1959.
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