established by Haber in, ‘Thermodynamics of Technical Gas Reactions’, Haber,
op. cit. (note 12), pp. 204–206.
22. The diffusion of the small hydrogen molecule into iron was later to become
of paramount importance in the history of the synthesis of ammonia
(Chap. 11). At the time neither Haber nor Le Rossignol realised this.
23. To generate the iron catalyst, the purest commercial iron oxide was obtained
and reduced in a stream of hydrogen at 1000 °C. There was, therefore, no
possible formation of nitride. Occasionally, ferrous oxalate was used instead.
For the nickel catalyst, the purest commercial nickel nitrate was treated with
silicic acid. The solid was dried and the metal produced by heating to 350–
400 °C in a stream of hydrogen, Haber noting that at this temperature ‘a
catalytically very effective product is received’. Chromium was prepared
electrolytically from a solution of the sulphate. It was easily removed from the
platinum electrode then ground down in a mortar. Manganese was obtained
electrolytically as a mercury amalgam. The mercury was removed in a vacuum and the manganese ground as before. Little did the workers know that
the eventual successful industrial catalyst was much more of a chemical
‘mongrel’ (Chaps. 10 and 11).
24. The distilled water used to ‘top up’ and ‘wash out’ was weakly alkaline against
the indicator ‘Jedeosin’ (Erythrosin B), but by the addition of 1.4 cc 0.02 N
HCl to a litre of the water it was made neutral to this indicator.
25. Between 25.1 and 25.2% nitrogen was usually confirmed—probably by
using Haber’s patented refractometer, (Chap. 2). Testing Gaseous Mixtures,
United States Patent Office, No. 830,225, Patented 04 September 1906.
26. Bodländer, Zeitschrift für Elektrochemie. 8, 833, (1902).
27. See R. Luther, Zeitschrift für Elektrochemie, 12, 97, (1906), for Haber’s
thermodynamic terminology, also quoted in Louis De Vries, German-English
Scientific Dictionary, 3rd Ed., McGraw-Hill. One might also refer to Lamb’s
translation of Haber’s book, Haber, op. cit. (note 12).
28. Haber only referred to the Nernst ‘approximation formula’ and presented just
one table, (viz, Table 5.2). The whole report of Haber’s ‘presentation’,
Nernst, op. cit. (note 3), was barely a page long—and much of that was taken
up with the retraction of his previous result at 1020 °C in 1905, Haber,
op. cit. (note 13).
29. J.E. Coates, ‘The Haber Memorial Lecture’, J. Chem. Soc., 1642–1672,
(1939).
30. Nernst was beguiled by the large yield of ammonia his experiments provided;
he didn’t question the possibility that his equilibrium could be poor—a fact
established later by Le Rossignol. Although he criticised Haber, his results
were at fault. Le Rossignol dealt with tiny yields, but the work was fastidious,
accurate and reproducible.
126
D. Sheppard
op. cit. (note 12), pp. 204–206.
22. The diffusion of the small hydrogen molecule into iron was later to become
of paramount importance in the history of the synthesis of ammonia
(Chap. 11). At the time neither Haber nor Le Rossignol realised this.
23. To generate the iron catalyst, the purest commercial iron oxide was obtained
and reduced in a stream of hydrogen at 1000 °C. There was, therefore, no
possible formation of nitride. Occasionally, ferrous oxalate was used instead.
For the nickel catalyst, the purest commercial nickel nitrate was treated with
silicic acid. The solid was dried and the metal produced by heating to 350–
400 °C in a stream of hydrogen, Haber noting that at this temperature ‘a
catalytically very effective product is received’. Chromium was prepared
electrolytically from a solution of the sulphate. It was easily removed from the
platinum electrode then ground down in a mortar. Manganese was obtained
electrolytically as a mercury amalgam. The mercury was removed in a vacuum and the manganese ground as before. Little did the workers know that
the eventual successful industrial catalyst was much more of a chemical
‘mongrel’ (Chaps. 10 and 11).
24. The distilled water used to ‘top up’ and ‘wash out’ was weakly alkaline against
the indicator ‘Jedeosin’ (Erythrosin B), but by the addition of 1.4 cc 0.02 N
HCl to a litre of the water it was made neutral to this indicator.
25. Between 25.1 and 25.2% nitrogen was usually confirmed—probably by
using Haber’s patented refractometer, (Chap. 2). Testing Gaseous Mixtures,
United States Patent Office, No. 830,225, Patented 04 September 1906.
26. Bodländer, Zeitschrift für Elektrochemie. 8, 833, (1902).
27. See R. Luther, Zeitschrift für Elektrochemie, 12, 97, (1906), for Haber’s
thermodynamic terminology, also quoted in Louis De Vries, German-English
Scientific Dictionary, 3rd Ed., McGraw-Hill. One might also refer to Lamb’s
translation of Haber’s book, Haber, op. cit. (note 12).
28. Haber only referred to the Nernst ‘approximation formula’ and presented just
one table, (viz, Table 5.2). The whole report of Haber’s ‘presentation’,
Nernst, op. cit. (note 3), was barely a page long—and much of that was taken
up with the retraction of his previous result at 1020 °C in 1905, Haber,
op. cit. (note 13).
29. J.E. Coates, ‘The Haber Memorial Lecture’, J. Chem. Soc., 1642–1672,
(1939).
30. Nernst was beguiled by the large yield of ammonia his experiments provided;
he didn’t question the possibility that his equilibrium could be poor—a fact
established later by Le Rossignol. Although he criticised Haber, his results
were at fault. Le Rossignol dealt with tiny yields, but the work was fastidious,
accurate and reproducible.
126
D. Sheppard