Harrison’s reagent

Harrison s reagent (a mixture of non-aqueous solutions of 4-(lV,iV-dimethylamino)-benzaldehyde and diphenylamine) yields a yellow, orange, or brown colour on contact with phosgene, according to concentration [165,1742]. A more marked colour change (yellow to blue) is observed when N,yV-dialkylanilines are coupled to the above aldehyde, and exposed to phosgene [1255] ... 

The color reaction of triphosgene with Harrison s reagent (a mixture of 4-(N,N-dimethylamino)benzaldehyde and diphenylamine in a non-aqueous solvent) yields a yellow to deep-orange hue, according to the concentration [19]. 

This qualitative test is also referred to as Harrison s test since he was the first to describe it in 1912. The test specimen is either boiled or padded with a reagent containing a mixture of silver nitrate (1%), sodium thiosulphate (4%) and sodium hydroxide (4%) and then steamed. Those parts where degradation takes place due to oxycellulose or hydrocellulose in a fabric will be stained black or dark grey due to the formation of silver by reduction. 

This is also referred to as Harrison s test. The reagent is a solution containing 1 per cent of silver nitrate, 4 per cent of sodium thiosulphate, and... 

We will see later that other reactions can be in competition with Reactions (3.2) and (3.3). Reaction (3.3) is possible only if the proton affinity of the analyte (affinity of the molecule for the proton) is higher than that of the reagent gas. By definition, the proton affinity of a molecule M is the variation of enthalpy associated with the reaction MH+ M + H+ in the gas phase. Table 3.1 taken from Harrison s book supplies proton affinity values for families of common organic compounds."... 

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