Solvent-Free Iodination of Organic Molecules Using the I2/Urea—H2O2 Reagent System.

ChemInform ◽  
2007 ◽  
Vol 38 (27) ◽  
Author(s):  
Jasminka Pavlinac ◽  
Marko Zupan ◽  
Stojan Stavber
Keyword(s):  
Organic Molecules ◽  
Solvent Free

Mechanochemistry for sustainable, efficient dehydrogenation/hydrogenation

2020 ◽  
Author(s):  
Blaine G. Fiss ◽  
Austin James Richard ◽  
Tomislav Friscic ◽  
Audrey Moores
Keyword(s):  
Ball Milling ◽  
Chemical Industry ◽  
Organic Molecules ◽  
Solvent Free ◽  
Chemical Transformations ◽  
Triple Bonds ◽  
Bulk Chemicals ◽  
Challenges And Opportunities ◽  
Hydrogenation Reactions ◽  
Solution Routes

Hydrogenation reactions are one of the pillars of the chemical industry, with applications from bulk chemicals to pharmaceuticals manufacturing. The ability to selectively add hydrogen across double and/or triple bonds is key in the chemist’s toolbox, and the enabling component in the development of sustainable processes. Traditional solution-based approaches to hydrogenation reactions are tainted by significant consumption of energy and production of solvent waste. This review highlights the development and applications of recently emerged solvent-free approaches to conduct the hydrogenation of organic molecules using mechanochemistry, i.e. chemical transformations induced or sustained by mechanical force. In particular, we will show how mechanochemical techniques such as ball-milling enable catalytic or stoichiometric metal-mediated hydrogenation reactions that are simple, fast, and are conducted under significantly milder conditions compared to traditional solution routes. Importantly, we highlight the current challenges and opportunities in this field, while also identifying exciting cases in which mechanochemical hydrogenation strategies lead to new, unique targets and reactivity.

scholarly journals Ozone-Mediated Amine Oxidation and Beyond: A Solvent Free, Flow-Chemistry Approach

2021 ◽  
Author(s):  
Eric Skrotzki ◽  
Jaya Kishore Vandavasi ◽  
Stephen Newman
Keyword(s):  
Organic Molecules ◽  
Flow Chemistry ◽  
Packed Bed ◽  
High Reactivity ◽  
Solvent Free ◽  
Packed Bed Reactor ◽  
Primary Amines ◽  
Amine Oxidation ◽  
Synthetic Utility ◽  
Free Oxidation

Ozone is a powerful oxidant, most commonly used for oxidation of alkenes to carbonyls. The synthetic utility of other ozone-mediated reactions is hindered by its high reactivity and propensity to over-oxidize organic molecules, including most solvents. This challenge can largely be mitigated by adsorbing both substrate and ozone onto silica gel, providing a solvent-free oxidation method. In this manuscript, a flow-based packed bed reactor approach is described that provides exceptional control of reaction temperature and time of this reaction to achieve improved control and chemoselectivity over this challenging reaction. A powerful method to oxidize primary amines into nitroalkanes is achieved. Examples of pyridine, C–H bond, and arene oxidations are also demonstrated, confirming the system is generalizable to diverse ozone-mediated processes.<br>

Solvent-free iodination of organic molecules using the I2/urea–H2O2reagent system

2007 ◽  
Vol 5 (4) ◽  
pp. 699-707 ◽  
Author(s):  
Jasminka Pavlinac ◽  
Marko Zupan ◽  
Stojan Stavber
Keyword(s):  
Organic Molecules ◽  
Solvent Free

scholarly journals Ozone-Mediated Amine Oxidation and Beyond: A Solvent Free, Flow-Chemistry Approach

2021 ◽  
Author(s):  
Eric Skrotzki ◽  
Jaya Kishore Vandavasi ◽  
Stephen Newman
Keyword(s):  
Organic Molecules ◽  
Flow Chemistry ◽  
Packed Bed ◽  
High Reactivity ◽  
Solvent Free ◽  
Packed Bed Reactor ◽  
Primary Amines ◽  
Amine Oxidation ◽  
Synthetic Utility ◽  
Free Oxidation

Ozone is a powerful oxidant, most commonly used for oxidation of alkenes to carbonyls. The synthetic utility of other ozone-mediated reactions is hindered by its high reactivity and propensity to over-oxidize organic molecules, including most solvents. This challenge can largely be mitigated by adsorbing both substrate and ozone onto silica gel, providing a solvent-free oxidation method. In this manuscript, a flow-based packed bed reactor approach is described that provides exceptional control of reaction temperature and time of this reaction to achieve improved control and chemoselectivity over this challenging reaction. A powerful method to oxidize primary amines into nitroalkanes is achieved. Examples of pyridine, C–H bond, and arene oxidations are also demonstrated, confirming the system is generalizable to diverse ozone-mediated processes.<br>

High Resolution Replication of Organoclay Surfaces

1982 ◽  
Vol 40 ◽  
pp. 576-577
Author(s):  
W. W. Barker ◽  
W. E. Rigsby ◽  
V. J. Hurst ◽  
W. J. Humphreys
Keyword(s):  
Clay Mineral ◽  
Organic Molecule ◽  
Organic Molecules ◽  
X Ray Diffraction ◽  
Xrd Pattern ◽  
X Ray ◽  
Naturally Occurring ◽  
Silicate Layers ◽  
Mineral Identification

Experimental clay mineral-organic molecule complexes long have been known and some of them have been extensively studied by X-ray diffraction methods. The organic molecules are adsorbed onto the surfaces of the clay minerals, or intercalated between the silicate layers. Natural organo-clays also are widely recognized but generally have not been well characterized. Widely used techniques for clay mineral identification involve treatment of the sample with H2 O2 or other oxidant to destroy any associated organics. This generally simplifies and intensifies the XRD pattern of the clay residue, but helps little with the characterization of the original organoclay. Adequate techniques for the direct observation of synthetic and naturally occurring organoclays are yet to be developed.

Direct phase determination in electron crystallography: small organic molecules

1992 ◽  
Vol 50 (2) ◽  
pp. 1166-1167
Author(s):  
Douglas L. Dorset
Keyword(s):  
Organic Molecules ◽  
Data Sets ◽  
Temperature Structure ◽  
3D Analysis ◽  
Intensity Data ◽  
Electron Crystallography ◽  
Phase Determination ◽  
Measured Intensity ◽  
3D Data

The quantitative use of electron diffraction intensity data for the determination of crystal structures represents the pioneering achievement in the electron crystallography of organic molecules, an effort largely begun by B. K. Vainshtein and his co-workers. However, despite numerous representative structure analyses yielding results consistent with X-ray determination, this entire effort was viewed with considerable mistrust by many crystallographers. This was no doubt due to the rather high crystallographic R-factors reported for some structures and, more importantly, the failure to convince many skeptics that the measured intensity data were adequate for ab initio structure determinations.We have recently demonstrated the utility of these data sets for structure analyses by direct phase determination based on the probabilistic estimate of three- and four-phase structure invariant sums. Examples include the structure of diketopiperazine using Vainshtein's 3D data, a similar 3D analysis of the room temperature structure of thiourea, and a zonal determination of the urea structure, the latter also based on data collected by the Moscow group.

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