Polymer and small molecule mechanochemistry: closer than ever

• José G. Hernández

Beilstein J. Org. Chem. 2022, 18, 1225–1235, doi:10.3762/bjoc.18.128

• transduction of mechanical cues with high directionality to the mechanophores [1][2][3][4]. In contrast, ball milling protocols have a more evident effect on the macroscopic level of the system, for instance, by causing comminution, amorphization, polymorphic transformations, structural defects, melting of the

Particle size effect in the mechanically assisted synthesis of β-cyclodextrin mesitylene sulfonate

• Stéphane Menuel,
• Sébastien Saitzek,
• Eric Monflier and
• Frédéric Hapiot

Beilstein J. Org. Chem. 2020, 16, 2598–2606, doi:10.3762/bjoc.16.211

• diffraction patterns recorded after various grinding times, and establish the extent of the amorphization of the reaction mixture during mechanochemical milling. The peaks corresponding to pure β-CD crystals decrease over time. Clearly, the polycrystalline β-CD powder becomes amorphous over time. The

• amorphization is usually described as a process starting on a thin surface layer and then propagating into the bulk [23], which impedes the structure and property characterization of the material. However, a significant fraction of residual crystalline domains still existed in the samples even after 1 h of

• should be aware of the highly speculative nature of such interpretations because of the multiple processes (amorphization, particle comminution, product removal to form a fresh reactant surface) operating during ball-milling. Conclusion While the nature of the grinding processes is still not entirely

Palladium nanoparticles supported on chitin-based nanomaterials as heterogeneous catalysts for the Heck coupling reaction

• Tony Jin,
• Malickah Hicks,
• Davis Kurdyla,
• Sabahudin Hrapovic,
• Edmond Lam and
• Audrey Moores

Beilstein J. Org. Chem. 2020, 16, 2477–2483, doi:10.3762/bjoc.16.201

• ChsNCs (Supporting Information File 1, Figure S3) where broadening of the peaks was observed for ChsNC as amorphization of the internal ChNC structure occurred during the deacetylation process. ChsNCs were readily suspendable in aqueous media and formed a transparent solution, owing to their positively

Natural dolomitic limestone-catalyzed synthesis of benzimidazoles, dihydropyrimidinones, and highly substituted pyridines under ultrasound irradiation

• Kumar Godugu,
• Venkata Divya Sri Yadala,
• Mohammad Khaja Mohinuddin Pinjari,
• Trivikram Reddy Gundala,
• Lakshmi Reddy Sanapareddy and
• Chinna Gangi Reddy Nallagondu

Beilstein J. Org. Chem. 2020, 16, 1881–1900, doi:10.3762/bjoc.16.156

• fresh catalyst (Figure 8a). It was also noticed that the broadening in the XRD pattern of the recovered catalyst had increased with an increase of the ultrasonication time. This clearly indicated that the amorphization of the recovered catalyst was enhanced by increasing the ultrasonication time

Mechanochemical amorphization of chitin: impact of apparatus material on performance and contamination

• Thomas Di Nardo and
• Audrey Moores

Beilstein J. Org. Chem. 2019, 15, 1217–1225, doi:10.3762/bjoc.15.119

• mechanochemical amorphization of chitin. We measured the crystallinity index of chitin after milling it in a vibration mill in an apparatus made of copper, aluminum, brass, tungsten carbide, zirconia, stainless steel, polytetrafluoroethylene (PTFE), or poly(methyl methacrylate) (PMMA). These materials offer a

• : amorphization; biomass; chitin; hardness; mechanochemistry; metal contamination; Introduction The last decade has seen a tremendous development in the field of mechanochemistry, which was notably covered in the New York Times in 2016 [1]. Yet, mechanochemistry is hardly a novel concept, since it is likely

• amounts of material from the jars and balls in the reagents and products as a contamination. Milling media can have a catalytic effect due to leaching or surface adsorption [7][35][36][37]. Contamination has been noted in alloying [26][38] as well as amorphization of hard materials [39], and could cause