Rapid, Solvent-Free Synthesis of Amorphous, Photoluminescent, Carbon Nanodots from Imidazole and Maleic Anhydride Solids

Abstract

A facile, rapid, and sustainable synthesis of amorphous, photoluminescent, carbon nanodots in high yields (∼51%), by cogrinding of maleic anhydride and imidazole, is reported for the first time. The heat liberated during the exothermic oligomerization of maleic anhydride, initiated by imidazole in the solid state, was identified to be the cause of carbonization of the reaction mixture. These carbon nanodots showed very low cytotoxicity toward mesenchymal stem cells, even at very high concentrations (1 mg/mL). Having the highest adsorption capacity for ammonia among unmodified carbons reported to date (∼19.3 mg/g), these carbon nanodots could be used for the removal of ammonia from the gas phase. In addition, these carbon nanodots could be used as an ionotropic cross-linker for chitosan, to prepare stable gels, suitable for a wide variety of applications. In contrast to the present solid-state methodologies which involve the use of hazardous chemicals or high temperatures, this solvent-free method of preparing carbon nanodots is sustainable, facile, safe, and inexpensive.

Highly Efficient Biobased Synthesis of Acrylic Acid

“…Moreover,r eproduction of the oxidation reaction led to inconsistent results in terms of conversion and selectivity.L iterature reports indicate that maleic anhydride can readily undergo polymerization by imidazoles. [25] While NMI acts as aligand for copper during the reaction, it is proposed that dissociation from the complex results to NMI acting as initiator for anionic polymerization of maleic anhydride.T he oxidation reaction was monitored over time by 1 HNMR spectroscopy (Supporting Information, page 6, Figure S1) indicating that, while hydroxybutenolide is converted and the amount of maleic anhydride increases in the first few hours of the reaction (63 %, 3h), it subsequently decreases over aprolonged period (27 %, 72 h), which is attributed to the anionic polymerization. In the attempt to prevent maleic anhydride from reacting,the oxidation was carried out in the absence of NMI.…”

One-step solvent-free synthesis of carbon dot-based layered composites exhibiting color-tunable photoluminescence

“…[7][8][9][10][11][12] Recently, green synthesis of these CDs has been intensively explored for the industrial production of CD-based materials towards a future sustainable society. [13][14][15][16][17][18] Our intention here is to demonstrate practical solvent-free synthesis of CDs in layered inorganic compounds as a green process to form luminescent composites (Fig. 1).…”

“…7–12 Recently, green synthesis of these CDs has been intensively explored for the industrial production of CD-based materials towards a future sustainable society. 13–18…”

Synthesis of Carbon Nanodots from Sugarcane Syrup, and Their Incorporation into a Hydrogel-Based Composite to Fabricate Innovative Fluorescent Microstructured Polymer Optical Fibers

“…There is a continuous search for greener and cheaper methods to produce CNDs with low polydispersity from renewable sources [ 14 , 15 , 16 , 17 , 18 ]. Nature offers a plethora of carbon sources that has motivated the investigation of a wide variety of carbon sources as raw materials to obtain CNDs, which include lignin biomass, waste paper, kitchen waste, starch, orange peels, potato, grass, soy milk, papaya, eggs, coffee grounds, hair, cow manure, among others [ 19 , 20 , 21 , 22 , 23 ].…”