Tetrabutylphosphonium cation

Table I. Organic compounds, which were mostly used in syntheses of zeolites of pentasil-type. Abbreviations are TPA for te-trapropylammonium cation, TEPA for triethylmonopropylam monium cation, TEA for tetrabutylanmonium cation, TBP for tetrabutylphosphonium cation, TPA for tripropylamine and CgDN for hexamethyldiamine...

Intermediate phase transfer catalysts such as tetrabutylphosphonium and ben-zyltriethylammonium cations have no strong effect either way, and will generally give a mixture of products. 

ESR data obtained on y-irradiation of tetraalkylphosphonium salts in solution (96% sulphuric acid) at 77 K differ markedly from those for the trialkylphosphonium ions44. The latter irradiation produces the expected phosphabetaine radical cation and, for example, tetrabutylphosphonium iodide has features assigned previously to I2 45. On the other hand, PH was not detected44,46. Trialkylphosphonium salts, such as trimethyl and triethyl compounds, produce radicals whose ESR spectra are characteristic of the radical cations of R3P +. The central region of the ESR spectra is dominated by features from... 

Absorption of C02 at ambient pressure using basic ILs have attracted much attention in recent years, such as IL consisting of an imidazolium cation with a primary amine moiety and tetrafluoroborate anion [3], tetrabutylphosphonium amino acids [73]. Chitin and chitosan can be dissolved in [BMIm]Cl [74] and so on. 

Even if anionic chaotropes are the most popular neoteric IPRs, polarizable cations such as sulfonium and phosphonium reagents showed single selectivity toward polarizable anions their behavior was rationalized on the basis of their chaotropicity. Probe anion retention generally increases in the order of tributylsulfonium < tetrabutylammonium < tetrabutylphosphonium. Interestingly, retention was found to be influenced by the kosmotropic/chaotropic character of both the IPR and the probe anion [93] and this confirms the peculiarities of hydrophobic ion-pairing. Quaternary phosphonium salts provided increased selectivity compared to ammonium in the IPC of heavy metal complexes of unithiol [112]. 

It was noted that moving from tetrabutylammonium to tetrabutylphosphonium salts with a common anion led to identical solvation properties. This reflects the relatively small differences between these cations. 

Amino acids (AA), as one of the most abundant biomaterials in nature, are known to be nontoxic, biodegradable, and biocompatible. They are excellent feedstocks for the synthesis of ILs, because of their reasonable cost and environment-friendly characteristics. In 2005, a group of amino acid ionic liquids (AAILs) was first synthesized by Fukumoto s group from 20 natural AA [85]. They prepared AAILs based on l-ethyl-3-methylimidazolium cation, [emim], by neutralization method. In this method, [emim]OH was prepared by anion exchange resin, followed by addition of [emim]OH to a slight excess of an equimolar AA aqueous solution to prepare salts and water as a by-product [86]. Further, they synthesized tetrabutylphosphonium-based AAILs ([TBP][AA]) by mixing AA with aqueous solution of tetrabutylphosphonium hydroxide ([TBP][OH]) [87]. Tao et al. [88] synthesized [AAE]N03 ILs ([AAE] stands for AA ester as cation and NO3 stands... 

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