The discovery of phosgene

Humphrey Davy himself, but by his younger brother Dr. John Davy [466b,466c]. These exchanges are described in some detail in Dobbin s extensive account of the history of the discovery of phosgene [540], and will be only summarised here. 

Murray chose to interpret Cruickshank s experiments [429a] by suggesting that the 

Murray s inability to observe a reaction between dry oximuriatic acid and carbon monoxide was reinforced, curiously, by the similar finding of a lack of action by Gay-Lussac and Thenard [727]. In a reply dated February 9, 1811 [466b], John Davy (while still a medical student) attributed the formation of the carbonic acid produced in Murray s 

In a further communication of August 9, 1811, entitled An Account of a New Gas, with a Reply to Mr. Murray s last Observations on Oximuriatic acid , John Davy announced the existence of a new gas which he declared was present in Mr. Murray s experiments without his knowledge of it [466c]. This gas, Davy states, was the cause for the phenomena that were attributed to the formation of carbonic acid gas  

The next step I took was to examine the gas, that resulted from the now evident action of oximuriatic gas on carbonic oxide. Mr. Brande was present at the time. 

---

Events leading to the discovery of phosgene - the nature of oximuriatic acid... 

The history of the discovery of phosgene began almost thirty years before John Davy s notable paper presented to the Royal Society on February 6, 1812 [467], which ended the then heated controversy concerning the nature of chlorine. 

The key passage, relating to the discovery of phosgene, is illustrated in Fig. 1.1. Significant portions of this text were iater published, in modified version, as parts of John Davy s "Memoirs of the Life of Sir Humphry Davy, Bart. LL.D. F.R.S." [467a Vol. 1 pp. 417-418] and "Collected Works of Sir Humphry Davy" [467b Vol. 1 pp. 122-124],... 

Dr. John Davy became a fellow of the Royal Society in 1834 and died in 1868, survived by a son and daughter [1742a]. A short biography has been written by Ross [1742a], although (somewhat surprisingly) his most marked contribution to science, the discovery of phosgene, is not mentioned. 

The reaction between ammonia and phosgene (in a 4 1 stoicheiometry) was first reported in 1812, in the paper in which John Davy reported the discovery of phosgene [467]. The white product was claimed by Regnault in 1838 [1696a] to be a mixture of ammonium chloride and an "isomeric carbamide of urea", but Hofmann [972a] and Natanson [1483aa] later correctly demonstrated that it was a mixture of ammonium chloride and urea itself. The overall reaction between phosgene and ammonia in benzene is thus deceptively simple [2168] ... 

I have much pleasure now in looking back on this happy period of my life, when the whole of my time was devoted to chemical studies and pursuits, - in their most interesting and fascinating form - and I shall never forget the lively interest which my Brother took in what I was doing. - When I ascertained the existence of phosgene gas he was out of town - on his return I related to him all the particulars -1 am quite sure he felt more pleasure than if he had made the same discovery himself... 

As discussed previously, the discovery of the chlorination of secondary phosphines with phosgene should make phosphinous halides more available (80). Disubstituted phosphinous halides suffer displacement of the halogen by Grignard reagents under mild conditions, but yields are variable. The early observations of Meisenheimer clearly demonstrated that diarylphosphinous chlorides are smoothly converted to tertiary phosphines in ether (142). 

Since the discovery of PTFE a considerable research efforts focused on the photo-initiated polymerization of TFE. Polymer has been produced in the mercury-sensitized photolysis of gaseous TFE. However, analysis showed perfluorocyclopropane to be the main product. At pressures less than 8 kPa it is reported to be the only product [695,696]. Photopolymerization of gaseous TFE has also been reported in the presence of mercury bromide, phosgene, and nitrous oxide [697 99]. Atkinson [697] has observed that mercury bromide activated by light of 365 nm initiates the photochemical polymerization of TFE. 

In spite of his neat discovery. Dr. Davy has not foreseen the prolific potentiality of phosgene as an outstanding building block and reagent in chemistry. However, while treating phosgene with ammonia, he was very close to another discovery of extreme importance, that of the elucidation of the nature of urea. 

In 1909 the German Chemist Fritz Haber discovered a catalyzed process [13], which allowed the synthesis of ammonia (NH3) from the elements hydrogen and nitrogen. He received the Nobel prize in chemistry for his discovery. The Nobel prize for Fritz Haber was a subject of controversy because Haber is also the inventor of war gas (phosgene COCI2), which killed hundreds of thousands of soldiers in World War I. Conscience-stricken, Haber s wife committed suicide. Carl Bosch succeeded to scale up Haber s synthesis from the laboratory scale to industrial production. After World War I other industrialized countries also introduced ammonia synthesis and therefore the consumption of hydrogen increased rapidly. 

---