Examples of Metal Deactivators

N -bis(salicyloyl)hydrazide can be prepared through the reaction of a salicylic acid alkyl ester and hydrazine. Alternatively, a thionyl chloride route is viable (4). Detailed examples of the synthesis are given in the literature (5). 

N -Bis(salicyloyl)hydrazide serves particularly as a metal deactivator in cable and wire insulation for power and communications engineering (1). This compound allows a non-hazardous processing in engineering applications due to a substantially reduced eye irritation in comparison to other metal deactivators. 

In addition to low molecular compounds, polyhydrazides of 3,3 -thiodipropionylhydrazide have been proposed as metal deactivators (6). These compoimds can be manufactured by the reaction of a 3,3 -thiodipropionic acid dihydrazide with a suitable bis(acid chloride). 

N -Bis(3,5-di-ferf-butyl-4-hydroxyphenylpropionyl)hydrazine 3-N-Salicyloylamino-l,2,4-triazole (Adekastab CDA-1) (8) Decamethylene dicarboxylic acid-bis(N -salicyloylhydrazide) (Adekastab CDA-6) (8) 

Isophthaloyl dihydrazide Sebacoyl bisphenylhydrazide N,N -diacetyladipoyl dihydrazide N,N -bis(salicyloyl)oxalyl dihydrazide N,N -bis(salicyloyl)thiopropionyl dihydrazide 2 3-Bis[[3-[3,5-di-fert-butyl-4-hydrox) henyl]propionyl]]propionohy-drazide (Irganox MD1024) (9) 

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Examples of metal deactivators are shown in Figure 18.2. Selected metal deactivators are shown in Table 18.1. 

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