Phosphonium iodide, preparation

The present preparation illustrates a general and convenient method for the fnms-iodopropenylation of an alkyl halide.4 The iodopropenyl-ated material is not usually stable but is a useful synthetic intermediate. For example, it forms a stable crystalline triphenylphosphonium salt for use in the Wittig reaction, and under Kornblum reaction conditions (DMS0-NaHC03, 130°, 3 minutes) it gives an (E)-a,/9-unsaturated aldehyde.4 In addition to the phosphonium salt described in Note 15, the following have been prepared (4-p-methoxyphenyl-2-butenyl)-triphenylphosphonium iodide [Phosphonium, [4-(4-methoxyphenyl)-2-butenyl]triphenyl-, iodide], m.p. 123-127° (2-octenyl)triphenyl-phosphonium iodide [Phosphonium, 2-octenyltriphenyl-, iodide], m.p. 98° and (2-octadecenyl)triphenylphosphonium iodide [Phosphonium, 2-octadecenyltriphenyl-, iodide], m.p. 50°. 

There have been several accidents with metalloids detonation with fluorine very violent reaction with boron at 700°C, and ignition with white phosphorus. In the last case, the dangerous character of the reaction of the preparation of hydrogen iodide by distillation of the phosphorus/moist iodide mixture was also mentioned. The formation of phosphonium iodide often causes the conduits of the apparatus to block, which causes the apparatus to detonate due to overpressure. Several accidents involve this factor, which is not due to a reaction that is intrinsically dangerous. 

During preparation of hydriodic acid by distillation of phosphorus and wet iodine, the condenser became blocked with by-product phosphonium iodide, and an explosion, possibly also involving phosphine, occurred. There is also a purification hazard. 

Phosphonium iodide PH4I (M.W. 161.93, b.p. 62.5°, density 2.86) is prepared somewhat tediously from white phosphorus and iodine [286] and was... 

Very pure phosphine is formed by the hydrolysis of phosphonium iodide with water, dilute acids or dilute bases 2. 4.107,109-114) or by the reduction of phosphorus trichloride with lithium in diethyl ether 7,us-ii7) Related to the latter is a method for the preparation of phosphine, described in the patent literature, where phosphorus trichloride vapour, diluted with nitrogen, is passed through a column filled with lithium hydride mixed with an inert material, such as sand, NaCl, KCl or similar materials... 

The reaction between dry phosphine and hydrogen iodide, first described in 1817 by J. J.Houtonde la Billardiere produces phosphonium iodide. The simplest laboratory preparation of this compound is by the hydrolysis of an intimate mixture of diphosphorus tetraiodide and white phosphorus According to X-ray diffraction investigations, phosphonium iodide crystallises in a caesium chloride type lattice 3m,32s). 326) hydrogen atoms... 

Chloral hydrate and chloral alcoholate react with phosphine in the presence of HCi to give compound 4 in the form of its monohydrates The preparation of this compound from chloral hydrate and phosphonium iodide has been previously described by Girard... 

Phosphonium iodide is used to prepare phosphine Physical Properties... 

Phosphonium iodide may be prepared by the action of phosphine with dry hydrogen iodide ... 

Iodoallenes are prepared from propargyl alcohols by means of phosphonium iodide produced in situ from triphenyl phosphite and methyl iodide. In addition, small amounts of the isomeric iodoacetylenes are formed in this process. 

Preparation of Phosphonium Iodide. Perform the experiment in a medium of dry carbon disulphide. Carbon disulphide is poisonous and readily ignites, its mixture with air is explosive. Work with it requires great care and attention. Distil carbon disulphide in a water bath in the absence of an open flame )... 

Preparation of Phosphorus Iodide Pgl. To prepare phosphorus iodide, one must have thoroughly dried carbon disulphide (see Preparation of Phosphonium Iodide ) and purified white phosphorus (see Preparation of Phosphorus Tribromide ). (Perform the experiment in a fume cupboard . ... 

Phosphine, generated by action of the alkali on phosphonium iodide, was shown to be pure by mass spectrometry. During a second preparation, an air leak developed during cold-trap transfer and an explosion occurred. Presence of diphosphane was suspected. See Phosphine (reference 2)... 

Step 1 The diol E must be protected (acetal, in this example) for the Wittig reaction to proceed. The Wittig reagent is prepared from the phosphonium iodide using sodium dimsylate, NaCH2S(0)CH3. 

Tertiary alkylphosphines can be prepared by reaction of phosphonium iodide with alcohols6 or by treatment of a... 

AN IMPROVED ALL-GLASS APPARATUS FOR THE PREPARATION OF PHOSPHONIUM IODIDE... 

Phosphonitrile chloride, trimeric and tetrameric, 6 94 Phosphonium iodide, 2 141, 143 all-glass apparatus for preparation of, 6 91... 

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