- Synthesis of monophosphines directly from white phosphorus
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Monophosphorus compounds are of enormous industrial importance due to the crucial roles they play in applications such as pharmaceuticals, photoinitiators and ligands for catalysis, among many others. White phosphorus (P4) is the key starting material for the preparation of all such chemicals. However, current production depends on indirect and inefficient, multi-step procedures. Here, we report a simple, effective ‘one-pot’ synthesis of a wide range of organic and inorganic monophosphorus species directly from P4. Reduction of P4 using tri-n-butyltin hydride and subsequent treatment with various electrophiles affords compounds that are of key importance for the chemical industry, and it requires only mild conditions and inexpensive, easily handled reagents. Crucially, we also demonstrate facile and efficient recycling and ultimately catalytic use of the tributyltin reagent, thereby avoiding the formation of substantial Sn-containing waste. Accessible, industrially relevant products include the fumigant PH3, the reducing agent hypophosphorous acid and the flame-retardant precursor tetrakis(hydroxymethyl)phosphonium chloride. [Figure not available: see fulltext.]
- Scott, Daniel J.,Cammarata, Jose,Schimpf, Maximilian,Wolf, Robert
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p. 458 - 464
(2021/04/09)
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- Comparative study of inclusion complexation of tetraalkylphosphonium and ammonium salts with cucurbit[7]uril
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Inclusion complexation of tetraalkylphosphonium salts (PSs) with cucurbit[7]uril (CB[7]) was studied spectrophotometrically using methylene blue as a chemical indicator. Differences in the inclusion behaviour caused by the central ions in PSs and tetraalkylammonium salts (ASs) are described herein. The inclusion complexation constant (K) of PS3 with a C3-alkyl chain is remarkably smaller than those of the other PSs, indicating that PS3 is most suitable for clathrate-hydrate formation in bulk solution. In the AS inclusions, AS4 with a C4-alkyl chain showed the small K value. Furthermore, the K values of PSs with CB[7] were measured under high pressure. The K values of CB[7] increased with increasing external pressure and decreasing solvent polarity. From the high-pressure results, the volume change (ΔVrepel) caused by water molecules released from the CB[7] cavity was evaluated. A volumetric study for the inclusion of PSs with CB[7] indicated that in PS6 and PS8 with long C6 and C8 chains, respectively, one alkyl chain was encapsulated in the CB[7] cavity. In the other PSs with short chains, two alkyl chains could be accommodated in the cavity. Based on the effects of temperature, substituents, and external pressure, differences in the inclusion mechanisms of PSs and ASs for CB[7] are discussed.
- Hagiwara, Seiya,Hanaya, Tadashi,Matsumoto, Yuki,Sueishi, Yoshimi
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- Effect of Cation on Physical Properties and CO2 Solubility for Phosphonium-Based Ionic Liquids with 2-Cyanopyrrolide Anions
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A series of tetraalkylphosphonium 2-cyanopyrrolide ([Pnnnn][2-CNPyr]) ionic liquids (ILs) were prepared to investigate the effect of cation size on physical properties and CO2 solubility. Each IL was synthesized in our laboratory and characterized by NMR spectroscopy. Their physical properties, including density, viscosity, and ionic conductivity, were determined as a function of temperature and fit to empirical equations. The density gradually increased with decreasing cation size, while the viscosity decreased noticeably. In addition, the [Pnnnn][2-CNPyr] ILs with large cations exhibited relatively low degrees of ionicity based on analysis of the Walden plots. This implies the presence of extensive ion pairing or formation of aggregates resulting from van der Waals interactions between the long hydrocarbon substituents. The CO2 solubility in each IL was measured at 22 °C using a volumetric method. While the anion is typically known to be predominantly responsible for the CO2 capture reaction, the [Pnnnn][2-CNPyr] ILs with shorter alkyl chains on the cations exhibited slightly stronger CO2 binding ability than the ILs with longer alkyl chains. We attribute this to the difference in entropy of reaction, as well as the variation in the relative degree of ionicity.
- Seo, Samuel,Desilva, M. Aruni,Xia, Han,Brennecke, Joan F.
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p. 11807 - 11814
(2015/09/15)
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