Butyl hexafluorophosphate

Butyl-3 -methylimidazolium hexafluorophosphate [BMIM] PFg Butyl Hexafluorophosphate... 

Cyclization takes place when tert-butylisocyanide, benzaldehyde, anilinium chloride, and carbonyl(dicyano)cyclopentadienyl ferrate are reacted, the carbene complex 42 being the result (95JOM(491)135). /50-butyraldehyde, tert-butyl isocyanide, ammonium hexafluorophosphate, and [(T -Cp)Fe(CO)(CN)2] give the cationic bis-carbene 43. 

The advantage of the stoichiometric technique is that it is extremely simple. Care has to be taken to remove all gases dissolved in the IL sample initially, but this is easily accomplished because one does not have to worry about volatilization of the IL sample when the sample chamber is evacuated. The disadvantage of this technique is that it requires relatively large amounts of ILs to obtain accurate measurements for gases that are only sparingly soluble. At ambient temperature and pressure, for instance, 10 cm of l-n-butyl-3-methylimida2olium hexafluorophosphate ([BMIM][PFg]) would take up only 0.2 cm of a gas with a Henry s law constant of... 

Figure 4.2-1 shows the calculated ab initio molecular structure of the ionic liquid [BMIM][PFg] (l-butyl-3-methylimidazolium hexafluorophosphate). 

Lipases from C. antarctica and P. cepacia showed higher enantioselectivity in the two ionic liquids l-ethyl-3-methylimidazolium tetrafluoroborate and l-butyl-3-methylimidazolium hexafluoroborate than in THE and toluene, in the kinetic resolution of several secondary alcohols [49]. Similarly, with lipases from Pseudomonas species and Alcaligenes species, increased enantioselectivity was observed in the resolution of 1 -phenylethanol in several ionic liquids as compared to methyl tert-butyl ether [50]. Another study has demonstrated that lipase from Candida rugosa is at least 100% more selective in l-butyl-3-methylimidazolium hexafluoroborate and l-octyl-3-nonylimidazolium hexafluorophosphate than in n-hexane, in the resolution of racemic 2-chloro-propanoic acid [51]. 

Coupling one of these cations with one of these anions gives an ionic molecule that has high electron density at the anionic end. The computer image at top right shows this for butyl methyl imidazolium hexafluorophosphate. 

Room-temperature ionic liquids have received much attention as green designer solvents. We first demonstrated that ionic liquids acted as good medium for lipase-catalyzed production of polyesters. The polycondensation of diethyl adipate and 1,4-butanediol using lipase CA as catalyst efficiently proceeded in l-butyl-3-methylimidazolinium tetrafluoroborate or hexafluorophosphate under reduced pressure. The polymerization of diethyl sebacate and 1,4-butanediol in l-butyl-3-methylimidazolinium hexafluorophosphate took place even at room temperature in the presence of lipase BC. ... 

Denk et al. reported the first synthesis of 4,5-unsubstituted [l,3,2]diazaphosphe-nium chloride, 47C1 from the dilithio reduction product 50 of 1,2-diiminoethane, via cyclic dichloro-diazasilane 51 by means of metathetical reaction of the latter with PC13 (Scheme 15) [46], l,3-Di-ferf-butyl-[l,3,2]diazaphosphenium tetrachlo-rogallate [46], hexafluorophosphate [52], tetrafloruborate [49], and l,3-dimesityl-[l,3,2] diazaphosphenium triflate [49] were obtained as stable crystalline solids from the... 

Scheme 6.93) [192]. Using either of the two solvent systems, all studied cycloaddition reactions were completed in less than 1 min upon microwave irradiation at 50 °C employing 3 mol% of the catalyst. An additional advantage of using the ionic liquid l-butyl-3-methylimidazolium hexafluorophosphate (bmimPF6) as solvent is that it facilitates catalyst recycling. 

Inter- and intramolecular hetero-Diels-Alder cycloaddition reactions in a series of functionalized 2-(lH)-pyrazinones have been studied in detail by the groups of Van der Eycken and Kappe (Scheme 6.95) [195-197]. In the intramolecular series, cycloaddition of alkenyl-tethered 2-(lH)-pyrazinones required 1-2 days under conventional thermal conditions involving chlorobenzene as solvent under reflux conditions (132 °C). Switching to 1,2-dichloroethane doped with the ionic liquid l-butyl-3-methylimidazolium hexafluorophosphate (bmimPF6) and sealed-vessel microwave technology, the same transformations were completed within 8-18 min at a reaction temperature of 190 °C (Scheme 6.95 a) [195]. Without isolating the primary imidoyl chloride cycloadducts, rapid hydrolysis was achieved by the addition of small amounts of water and subjecting the reaction mixture to further microwave irradia-... 

Indole 73 can be selectively alkylated [110] (Scheme 8.75) by benzyl bromide to give 74 in high yield (>90%) when the reactants were mixed with l-butyl-3-methylimi-dazolium hexafluorophosphate ([bmim][PF6]) as polar solvent and the reaction was performed with brief (1 min) microwave irradiation at 180 °C. Product 74 was fully extracted with diethyl ether and [bmim][PF6] was reused in another cycle of synthesis. 

In 2002 Mehnert and co-workers were the first to apply SILP-catalysis to Rh-catalysed hydroformylation [74], They described in detail the preparation of a surface modified silica gel with a covalently anchored ionic liquid fragment (Scheme 7.7). The complex N-3-(3-triethoxysilylpropyl)-4,5-dihydroimidazole was reacted with 1-chlorobutane to give the complex l-butyl-3-(3-triethoxysilylpropyl)- 4,5-dihydroimidazolium chloride. The latter was further treated with either sodium tetrafluoroborate or sodium hexafluorophosphate in acetonitrile to introduce the desired anion. In the immobilisation step, pre-treated silica gel was refluxed with a chloroform solution of the functionalised ionic liquid to undergo a condensation reaction giving the modified support material. Treatment of the obtained monolayer of ionic liquid with additional ionic liquid resulted in a multiple layer of free ionic liquid on the support. 

B = molybdocene(IV) dithiol (70b). The solitaire porphyrazines exhibited rich redox chemistry, and could be oxidized with ferrocenium hexafluorophosphate to yield the paramagnetic Mo(V) species H2[pz(A3B)], A = di -ferf-butyl phenyl, B = molybdocene(V) dithiol (72a) and H2[pz(A3B)], A = dipropyl, B = molybdocene(V) dithiol (72b), which were studied by EPR (Scheme 13). Additionally, 70a was centrally metalated with Cu(II), to form Cun[pz(A3B)], A = di-ferf-butyl phenyl, B = molybdocene(IV) dithiol (71), which was then oxidized to Cun[pz(A3B)], A = di-terf-butyl phenyl, B = molybdocene(V) dithiol (73) and its magnetic properties investigated. 

These changes in anion and cation were not merely a case of methyl, ethyl, propyl, butyl, and then futile. The change of anion dramatically affects the chemical behavior and stability of the ionic liquid the change of cation has a profound effect on the physical properties, such as melting point, viscosity, and density readily can be seen by examining the phase diagrams for the hexafluorophosphate and tetrafluoroborate salts (see Figures 5.5 and 5.6, respectively). 

Hexafluorophosphate salts behave similarly.101 The diazonium tetrafluoroborates can be prepared either by precipitation from an aqueous solution by fluoroboric acid102 or by anhydrous diazotization in ether, THF, or acetonitrile using /-butyl nitrite and boron trifluoride.103 104 Somewhat milder conditions can be achieved by reaction of aryldiazo sulfide adducts with pyridine-HF in the presence of AgF or AgN03. 

IIH-Imidazollum, 1-butyl-3-methyl-, chloride (1-) 1H-lmldazollum, 1-butyl-3-methyl-, tetrafluoroborate (1-) 1H-lmldazollum, 1-butyl-3-methyl-, hexafluorophosphate (1-)]... 

C. 1- Butyl-3-methylimidazolium hexafluorophosphate. A 1-L, one-necked, round-bottomed flask (Note 13) is charged with 65.6 g (0.37 mol, 1 equiv) of 1- butyl-3-methylimidazolium chloride, and 69.3 g (0.37 mol, 1 equiv) of potassium hexafluorophosphate (Note 19) in 70 ml of distilled water. The reaction mixture is stirred at room temperature for 2 hr affording a two-phase system. The organic phase is washed with 3 X 50 mL of water and dried under reduced pressure (0.1 mbar, 0.001 mm). Then 100 ml of dichloromethane and 35 g of anhydrous magnesium sulfate are added. After 1 hr, the suspension is filtered and the volatile material is removed under reduced pressure (0.1 bar, 0. 1 mm) at 30°C for 2 hr to afford 86.4 g (0.29 mol, 81%) of 1- butyl-3-methylimidazolium hexafluorophosphate as alight yellow viscous liquid, mp 10°C (Notes 20 and 21). 

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