Synthetic uses of thionyl chloride

El‐Sakka, Ibrahim A.; Hassan, Nasser A.

doi:10.1080/17415990500031187

Cited by 24 publications

(16 citation statements)

References 132 publications

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“…One key feature that all the organic species have in common is that they can undergo charge‐transfer interactions with SOCl 2 20. 26, 31 Although no quantitative analysis has so far been carried out to answer the question of why organicus liquor regius with different compositions show different reactivity toward different noble metals, it can reasonably be assumed that the dissolution selectivity derives from the tunable interaction between SOCl 2 and the organic solvent/reagents. Further systematic fundamental studies on organicus liquor regius are promising directions for future research.…”

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confidence: 99%

“Organic Aqua Regia”—Powerful Liquids for Dissolving Noble Metals

et al. 2010

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The dissolution of noble metals is important for metallurgy, catalysis, organometallic chemistry, syntheses and applications of noble-metal nanoparticles, and recycling of noble metals. Aqua regia ("royal water") has been used for centuries as a powerful etchant to dissolve noble metals. The beauty of aqua regia is that the simple 1:3 mixture of concentrated nitric and hydrochloric acids can dissolve noble metals such as gold, palladium, and platinum, although these metals are not soluble in either of the acids alone. We show that simple mixtures of thionyl chloride (SOCl 2 ) and some organic solvents/reagents (pyridine, N,N-dimethylformamide, and imidazole) can also dissolve noble metals with high dissolution rates under mild conditions. We name these mixtures "organicus liquor regius".[1] The discovery of this solvent system is of unprecedented scientific significance and engineering value: Compared with inorganic chemistry, organic chemistry provides precise control over chemical reactivity, and the ability to tailor organic reactions enables the selective dissolution of noble metals. By varying the composition of organicus liquor regius we have for the first time realized the selective dissolution of noble metals, namely, the dissolution of Au and Pd from a Pt/Au/Pd mixture and of Au from an Au/Pd mixture. Selective dissolution is important for many applications, especially for recycling noble metals. The global energy crisis demands green energy technologies, which will undoubtedly require increased resources of noble metals. However, noble metals are scarce on earth; thus, the ability to recover high-purity noble metals by recycling processes will be paramount. Among the noble metals, Pt is used most widely as a catalyst in many green technologies, in particular, proton-exchange membrane (PEM) fuel cells. [2][3][4] The recycling of Pt, however, has long been a challenging issue: Current recycling technologies are complicated, and rely on the dissolution of Pt in strong inorganic acids and the subsequent separation of the dissolved Pt from solution. [5][6][7] The nonselectivity of the inorganic acids results in the dissolution of other noble metals such as Ag, Au, and Pd at the same time as Pt. This lack of selectivity limits the quality of the recycled Pt. Therefore, an improved route for Pt recycling-both in terms of quality and efficiency-requires a selective dissolution process, which would remove the noble metal impurities (Ag, Au, Pd, etc.) before the final dissolution of Pt. Preliminary investigations on a few non-aqueous solutions for dissolving noble metals have been carried out, [8][9][10][11] but they showed unsatisfactory solubility, [9][10][11][12] selectivity, [9][10][11][12] efficiency, [8,10] stability, [11] and simplicity.[8-10] These etchants are not ideal because of the intrinsic inorganic chemistry associated with conventional oxidizers of noble metals (halogens and oxygen). [8,9,11] Organicus liquor regius oxidizes noble metals by a different mechanism. Figure 1 shows a graph of the diss...

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“Organic Aqua Regia”—Powerful Liquids for Dissolving Noble Metals

et al. 2010

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“…On the other hand, a significant amount (6.8%) of the S 2p signal was also found for Ch-Cl sample, in the correspondence of the binding energy of S 2p 3/2 , and in particular at 164.2 eV that is in the correspondence of the signal expected for S-C covalent bonds [50]. The formation of this bond is probably ascribable to the high reactivity of SOCl 2 [51]. A small amount (0.4%) of S-C bond was also found for GO-Cl ( figure 1(m)).…”

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confidence: 54%

Electrochemical sensing of glucose by chitosan modified graphene oxide

et al. 2020

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Graphene oxide (GO) coated electrodes provide an excellent platform for enzymatic glucose sensing, induced by the presence of glucose oxidase and an electrochemical transduction. Here, we show that the sensitivity of GO layers for glucose detection redoubles upon blending GO with chitosan (GO +Ch) and increases up to eight times if covalent binding of chitosan to GO (GO−Ch) is exploited. In addition, the conductivity of the composite material GO−Ch is suitable for electrochemical applications without the need of GO reduction, which is generally required for GO based coatings. Covalent modification of GO is achieved by a standard carboxylic activation/amidation approach by exploiting the abundant amino pendants of chitosan. Successful functionalization is proved by comparison with an ad-hoc synthesized control sample realized by using non-activated GO as precursor. The composite GO−Ch was deposited on standard screen-printed electrodes by a dropcasting approach. Comparison with a chitosan-GO blend and with pristine GO demonstrated the superior reliability and efficiency of the electrochemical response for glucose as a consequence of the high number of enzyme binding sites and of the partial reduction of GO during the carboxylic activation synthetic step.

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“…It is known that SOCl 2 beside chlorinating action can act as an oxidant [4,5], especially when the reactions are performed at heating. For instance, the 1,4-dihydroxynaphthalene similar in the structure to thioxanthenone I at heating with SOCl 2 in benzene was converted into 1,4-naphthoquinone, and when this reaction was carried out in the presence of pyridine 2,3-dichloronaphthoquinone-1,4 was obtained [6].…”

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“…Based on the published data compiled in the review [4] we chose as one of such reagents the thionyl chloride whose mechanism of chlorination still remained incompletely understandable. It is known that SOCl 2 beside chlorinating action can act as an oxidant [4,5], especially when the reactions are performed at heating.…”

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