Description
Adipic dihydrazide (ADH) is the most suitable hydrazide cross-linking agent, and ADH has been widely used in water-based paint emulsions in combination with diacetone acrylamide. ADH is weakly alkaline, and there is a possibility of agglomeration when solid ADH is added directly to the emulsion, so usually ADH should be dissolved in hot water before use.
Chemical Properties
white to slightly yellow crystalline powder
Uses
Adipic dihydrazide is used as a formaldehyde scavenger and reacts with formaldehyde, thereby preventing the volatilizing of formaldehyde in the air. It is also employed as a paint additive and coating additive. It is also used as an intermediate. Further, it is used for cross-linking water-based emulsions and as a hardener for certain epoxy resins, which finds application in powder coating.
Uses
Adipic acid dihydrazide is a homobifunctional cross-linking reagent specific for aldehydes resulting in relatively stable hydrazone linkages. Adipic acid dihydrazide is typically, used in the linking of glycoproteins, such as antibodies, in a site specific fashion following periodate oxidation. Oxidation and coupling may conveniently be performed at pH 5.0 due to the low pKa of the hydrazide which avoids competition by primary amines.
Flammability and Explosibility
Non flammable
reaction suitability
reagent type: cross-linking reagent
Synthesis
General method: 7.6 g (100.0 mmol) of solid hydrazine (H3N + NHCO2-) was mixed with adipic acid (7.3 g, 50.0 mmol) in a mortar and pestle under solvent-free conditions for 10 min, followed by a stirring reaction for 5 h at 100 °C. The structure and composition of the reaction products were confirmed by 400 MHz NMR (nuclear magnetic resonance) and elemental analysis. The analysis showed that the product was hexanedihydrazide (C6H14N4O2) with ≥96% conversion and ≥95% yield (8.27 g).
Alternative method: 10 g of decane was used as solvent and the reaction conditions were adjusted to stirring at 110 °C for 12 h, followed by filtration and separation operations. The rest of the steps were the same as in the generalized method. The product was analyzed as hexanedihydrazide (C6H14N4O2) with 97% conversion and 93% yield.
Substitution: 5.0 g (100.0 mmol) of hydrazine hydrate was used in place of the solid hydrazine and 10.12 g (100.0 mmol) of diethyl adipate was used in place of adipic acid. The reaction was stirred at 75 °C for 5 h under the condition of 10 g ethanol as solvent. The product was analyzed as hexanedihydrazide (C6H14N4O2) with 89% conversion and 83% yield.
References
[1] Patent: KR2015/88523, 2015, A. Location in patent: Paragraph 0128; 0137; 0148-0149
[2] Organic Syntheses, 1956, vol. 36, p. 72,Note 7
[3] Justus Liebigs Annalen der Chemie, 1929, vol. 475, p. 122
[4] Journal fuer Praktische Chemie (Leipzig), 1915, vol. <2> 91, p. 23
[5] Journal fuer Praktische Chemie (Leipzig), 1981, vol. 323, # 3, p. 360 - 366
