Alkylations phosphine, tris

Quaternary phosphonium iodides are also good choices for the iodide salt catalyst component because they are highly active and, in some cases, soluble in the reaction and recovery processes. The simple quaternization of tri(n-alkyl)phosphines or triarylphosphines with n-alkyl iodides produces a wide variety of low cost phosphonium iodide salts ... 

The tetrakis-phosphino and -arsino complexes reported in Table 3 have very different thermal and air stabilities. In general, complexes with alkyl-phosphines and -arsines are air-unstable or pyrophoric. The tetrakis(arylphosphino) complexes (but not the bis or tris derivatives) are moderately air- and heat-stable, and the tetrakis phosphites may be handled in the atmosphere. Ni(PF3)4 is a stable liquid compound, whereas Ni(PCl3)4 and Ni(PBr3)4 are solids and stable only in dry air. 

Zhu, Y., Song, C. 1992. Recovery of neptunium, plutonium and americium from highly active waste. Tri-alkyl phosphine oxide extraction. In Transuranium Elements A Half Century. Morss, L.R. Fuger, J., Eds. ACS, Washington, DC, pp. 318-330. 

In Figure 1, the observed reactions are indicated in the context of a proposed catalytic scheme for terminal hydroformy-lation. The reaction pathway involving the alkyl phosphine intermediate (VIII) is the most likely. Overall, the results of the NMR studies provide consistent explanations for the process parameters of selective hydroformylation, particularly of the low pressure continuous product flashoff process (.5,15). it was shown that, in contrast to prior indications (3), the tris-phosphine complex (I) is a remarkably stable and favored species in the presence of excess phosphine and H2. This complex (I) is postulated to have a key role in the reversible generation and... 

Tri- -butyl phosphate is the work horse of the nuclear industry and is being used at various stages of nuclear fuel cycle. Apart from alkyl phosphates, tri-alkyl phosphine oxides are also used in many plant scale operations as well as in laboratory scale analytical separations. Minimizing their inventory in such separations through SLM methods though professed has not found industrial scale applications. Some of the laboratory scale applications of alkyl phosphates and tri-alkyl phosphine oxides as carriers in SLM will be discussed in this section (Table 31.7). 

No phosphonitrilic alkyls have been obtained. Stokes 85) continued the work of Couldridge 20) on the reaction of zinc ethyl with the tri-meric chloride at high temperatures a violent reaction took place, but no identifiable products could be isolated. It is probable that alkyl phosphines were formed. W. Philpott 2) found the trimeric chloride in ethereal solution to be unreactive to methyl Grignard reagents and to aluminum alkyls. Unsuccessful attempts have been made by H. T. Searle 2) to prepare the methyl derivatives by reaction of Me2PCls with ammonium chloride, either dry or in tetrachloroethane. Most of the expected hydrogen chloride is evolved, but ring closure does not take place. 

Phosphine oxides. Few molecular complexes of trivalent transplutonium elements have been reported. Several studies examine the extraction chemistry of Am, Cm, and Bk with a combination of /3-diketones and tri-n-alkyl phosphine oxides and tiialkylphosphates. From these, compounds reported to be of the formula AnF3(R3PO) c (An = Am, Cm R = n-octyl, Bu"0) were isolated, where L = CF3COCHCOR (R = Me, CF3, Bu ). The stoichiometry of the complexes (An P=0) was not always reported. The complex Am(CF3COCHCOCF3)3[OP(OBu )3]2 is reported to be volatile at 175 °C. ... 

Air oxidation of a variety of aliphatic and alkyl aromatic compounda air oxidation of p-nitrotoluene sulfuric acid substitution chlorination of a variety of organic compounds reaction between isobutylene and acetic acid oxidation of ethylene to acetaldehyde (Wacker processes) hydrochlorination of olehns absorption of phosphine in an aqueous soluhon of formaldehyde and hydrochloric acid acehc acid from the carbonylation of methanol oxidation of tri-alkyl phosphine dimerization of olefins. 

Preparation of Xi02. Using stable CLAs, Shi et al. [74] investigated the extraction and phase behaviors of tri-octyl phosphinic oxide (TOPO [or tri-alkyl phosphinic oxide TRPO])-kerosene/H2S04-Ti(IV) systems. They found that, under favorable hydrolysis conditions, a porous spherical Ti02 was obtained after the hydrolysis of Ti(IV) in the inner organic phase loaded with Ti(IV). 

The authors found that branched alkyl phosphines were not useful at all, whereas aryl phosphines afforded 1145 in acceptable yield but modest trans/cis selectivity (Scheme 1.298). However, both triethylphosphine and tri- -butylphosphine produced 1145 in nearly quantitative yield with 100 0 trans/cis selectivity. Operationally, the phosphonium salts were generated in situ, triethylphosphine was the reagent of choice. Similarly, the tranr-2-alkenyl bis- and ttis-oxazoles 1147—1150 were readily prepared. A further application of this methodology for the synthesis of ulapuahde A is discussed in Section 1.5.6. 

The air-stabilities of the complexes in Table I vary widely. Isocyanide complexes and complexes of the alkyl phosphines are very air sensitive or pyrophoric. The aryl phosphine complexes are moderately air sensitive the phosphite complexes can be handled in air but should be stored in an inert atmosphere. The phosphite complexes are insoluble in polar solvents such as alcohols and water, and soluble in hydrocarbons. Aryl phosphine complexes are soluble in aromatic solvents or tetrahydrofuran and insoluble in alkanes and alcohols. The alkyl phosphine complexes are soluble in ethers and hydrocarbons the triethylphosphine complex dissociates to the deep-purple tris complex, and is protonated by alcohols. 

The reactions of rhenium(V) oxo-alkyl-phosphine complexes with various alkynes were studied and the X-ray crystal structure of [Re(=0)Mc3(PhC>CPh)] was reported OO. The synthesis of a number of ibenium(I) tris-alkyne complexes was reported and [Re(OSiMe3)(MeCjCMe)3] characterised by X-ray diffraction Oi. The synthesis of a series of bis-imido alkyne and imido bis-alkyne rhenium complexes of the type [Re(NAr)2Cl(RCSCR)] and [ReCl(NAr)(NpGCNp)2] has been reported302 and the electrtxiic structures of the compounds investigated by Extended Huckel molecular mbital calculations. 

Buriak and co-workers chose a different modification strategy to Crabtree s catalysts and they replaced the pyridine with various alkyl phosphines. Optimization studies revealed that complex [(IMes)Ir(COD)(PBu3)]BARF 5 (BARF = tetrakis[3,5-bis(triflouromethylphenyl)borate]) was the most stable and displayed similar activity to 3. Furthermore, 5 was active for highly hindered tri- and tetrasubstituted alkenes at 1 atm pressure of H2 in the presence of air. 

The first polyphosphino maeroeyeles designed speeifieally for use as transition metal binders were reported in 1977 in back-to-baek eommunications by Rosen and Kyba and their eoworkers. The maeroeyeles reported in these papers were quite similar in some respeets, but the synthetic approaches were markedly different. DelDonno and Rosen began with bis-phosphinate 18. Treatment of the latter with Vitride reducing agent and phosphinate 19, led to the tris-phosphine,20. Formation of the nickel (II) complex of 20 followed by double alkylation (cyclization) and then removal of Ni by treatment of the complex with cyanide, led to 21 as illustrated in Eq. (6.15). The overall yield for this sequence is about 10%. 

Under similar conditions, perfluoroalkyl iodides react with alkyl phosphates to give fluorinated phosphine oxides, phosphinates, and phosphines [54 (equation 49) The product formed depends upon the stoichiometry and type of iodide used. When sodium alkyl trithiocarbonates are used as substrates, perfluoroalkyl tri-thiocarbonates ate formed [55]. 

Alkyl lithiums Dodecacarbonyltetracobalt Barium sulphide Tri isopropyl phosphine... 

A. Nucleophilic Reactions of the P=0 Group.—Tris(trifluoromethyl)-phosphine oxide (33) reacts with hexamethyldisiloxane to give a phos-phorane, whose n.m.r. spectrum at — 140 °C shows non-equivalent trifluoromethyl groups. Although this unusual reaction clearly involves nucleophilic attack of the phosphoryl oxygen on silicon at some stage of the reaction, a full study of the mechanism has not been published. Tertiary phosphine oxides can be converted cleanly into dichlorophos-phoranes (34) by treatment with two moles of phosphorus pentachloride. Alkylation of the sodium salt of tetraphenylmethylenediphosphine dioxide (35) with alkyl halides, in dimethyl sulphoxide, has been reported to... 

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