Table 1.

Main reaction types used to modify cellulose REGs and typical reaction conditions covering homogeneous (*) and heterogeneous systems.

Reaction type	Reactants	Medium, pH conditions/catalysis	Temperature, duration	Ref.
ligation	aliphatic/aromatic hydrazine analogues[a]	aqueous, (mostly) alkaline	25–35 °C, 24–72 h	[76, 77, 78, 79, 80]
		DMSO (anhydrous), Ar atmosphere	50–60 °C, 4 days	[109]
	hydroxylamines	aqueous, acidic or DMAc/LiCl (2.5 % w/v), Et3N*	40 °C, up to 700 h	[73, 74, 75]
	thiosemicarbazide	aqueous, acidic	60–65 °C, 90 min	[20, 52]
		NMMO/water (80/20, v/v)*	60 °C, 90 min	[81, 82, 83]
reductive amination	1° amine ligands + reducing agent	aqueous buffer, acidic or alkaline	70 °C, 24–72 h	[87, 88, 89, 90]
		MeOH/acetic acid	50 °C, 12–16 h	[54]
		DMF	RT or 70 °C, 1 or 3 days	[110]
		DMAc/LiCl*	70 °C, 24 h	[111]
Pinnick oxidation & amide coupling	1) NaClO2	1) aqueous, acidic	1) RT, 20–48 h	[22, 88, 89, 103, 104, 105]
	2) 1° amine ligands + coupling agents	2) aqueous, pH switch to alkaline	2) RT, 2 h–3 d	[88, 89, 103, 104, 105]
		aqueous, pH 5	4 °C, 24 h	[22]
Knoevenagel condensation	1,3‐diketones	aqueous bicarbonate, pH 8.5	80–90 °C, 4–48 h	[75]

[a] Characterized by hydrazine core (NH₂‐NH‐R).