Chemical functionalization of cellulosic materials with diazo compounds
A method for chemically functionalizing a cellulosic material using a diazo compound, and the functionalized cellulosic materials obtained by the method. The cellulosic materials may be functionalized with a functional groups selected from hydrophobic agents, catalyzing agents, sensing agent, diagnostic agents, printing agents chelating agents, ligands, antioxidants, antimicrobial agents, or drugs. Also, the uses of functionalized cellulosic materials obtained by the method in a variety of applications.
1 . A method for functionalizing a cellulosic material, comprising a step of:
contacting said cellulosic material with a diazo compound to obtain a functionalized cellulosic material,
wherein the diazo compound is stabilized by at least one electron-withdrawing group and has general formula R′R 2 C═N 2 , wherein R 1 and R 2 are substituents independently selected from acyl, aldehyde, amide, ester, nitrile, nitro, sulfonyl and aryl groups, or wherein R 1 is selected from acyl, aldehyde, amide, ester, nitrile, nitro, and sulfonyl groups and R 2 is a hydrogen or an alkyl group, or R 1 is selected from aryl groups and R 2 is an alkyl group, or wherein the diazo compound has general formula:
2 . The method according to claim 1 , wherein the cellulosic material is a mercerized cellulosic material.
3 . The method according to claim 1 , wherein the functionalization takes place via formation of an ether linkage.
4 . The method according to claim 1 , wherein the cellulosic material is in the form of fabric, paper or cardboard.
5 . The method according to claim 1 , wherein the cellulosic material comprises pristine cellulose.
6 . The method according to claim 1 , wherein the cellulosic material consists of pristine cellulose.
7 . The method according to claim 1 , wherein the diazo compound stabilized with at least one electron-withdrawing group has one of the following formula:
8 . The method according to claim 1 , wherein the functionalization takes place in a solvent selected from the group consisting of non-polar solvents, polar aprotic solvent, and any combination thereof.
9 . The method according to claim 1 , wherein the functionalization takes place at a temperature comprised between room temperature and reflux temperature.
10 . The method according to claim 1 , wherein the functionalization takes place in the presence of a rhodium (II) carboxylate used as catalyst or in the presence of a photochemical activation.
11 . The method according to claim 1 , wherein the functionalization takes place in the absence of a catalyst and in the absence of any photochemical activation.
12 . The method according to claim 1 , wherein said method is for functionalizing a cellulosic material with a functional group selected from the group consisting of: hydrophobic agents, catalyzing agents, sensing agents, diagnostic agents, printing agents, chelating agents, ligands, antioxidants, antimicrobial agents, and drugs,
wherein R 1 or R 2 is said functional group or each of R 1 and R 2 is said functional group, or
wherein said method further comprises a step of modifying, with said functional group, the functionalized cellulosic material obtained by contacting the cellulosic material with the diazo compound.
13 . The method according to claim 12 , wherein the hydrophobic agent belongs to the family of saturated fatty acids, to the family of diterpenes, or the family of sterols, or wherein the hydrophobic agent is 1-adamantanecarboxylic acid.
14 . The method according to claim 13 , wherein the hydrophobic agent is selected from the group consisting of cholesterol, palmitic acid and abietic acid.
15 . The method according to claim 1 , further comprising a step of using the functionalized cellulosic material for the fabrication of one of: a hydrophobic cellulosic material, a packaging material, a cellulose-supported catalyst or a security element.
16 . The method according to claim 1 , further comprising a step of using the functionalized cellulosic material obtained in the fabrication of an item useful in packaging, in catalyst, in filtration, adsorption and water treatment, in remediation, in medicine, in anti-counterfeiting, in paper-based electronics or in the fabrication of clothes, protective garments, health-care materials, medical devices, fiduciary items, official documents, or identifiers.