Phosphonium iodide

Phosphonium iodide was first prepared by Billardiere in 1817, by mixing dry phosphine and hydrogen iodide. This 

Apparatus. The apparatus is set up as shown in Fig. 15. A is a dropping funnel B is a T tube C is a 1000-ml. reaction flask H is a thin-waUed glass tube 2 cm. in diam- 

J and K contain water to remove excess hydrogen iodide and to indicate the rate of flow of gases through the system. M is a pressure equalizer to allow liquid in A to flow smoothly into C. Rubber stoppers are used throughout. The outlet L leads to an efficient hood for disposal of excess 

Preparation of Phosphorus-Diphosphorus Tetraiodide. Twenty-five grams of white phosphorus is cut into small pieces (Caution. Cut under water ) each of which is dried individually with absorbent paper and quickly placed in a 300-ml. flask (not the 1000-ml. flask in Fig. 15) from,which the air has been displaced by carbon dioxide. During this operation, and subsequently until the phosphorus is entirely dry, carbon dioxide is passed through the flask. Then 25 to 30 ml. of carbon disulfide is added through a funnel and the mixture shaken tmtil the phosphorus has dissolved. 

The funnel is removed and 44 g. of iodine is added in small portions, with constant shaking and cooling. A condenser is attached to the flask, and carbon disulfide is removed by immersing the flask in warm water. Volatilization of the last traces of carbon disulfide may be accomplished by passing a slow stream of carbon dioxide through the apparatus. 

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The reaction of potassium hydroxide solution with phosphonium iodide also gives pure phosphine ... 

Patents on the catbonylation of methyl chlotide [74-87-3] using carbon monoxide [630-08-0] in the presence of rhodium, palladium, and tidium complexes, iodo compounds, and phosphonium iodides or phosphine oxides have been obtained (26). In one example the reaction was conducted for 35... 

Some compounds are named as derivatives of the simple phosphoms hydrides (phosphines). For example, dimethylphosphine [676-59-5], (CH2)3PH triphenylphosphine oxide [791-28-6], (CgH3)3P=0 1,2-dimethyldiphosphine [53684-00-7], CH PHPHCH diethyliodophosphine [20472-47-3], (C2H3)2PI phosphonium iodide [12125-09-6], PH" P tetramethylphosphonium chloride [1941 -19-1], (CH3) P" C1 and phenylphosphonium bromide [55671-96-0], CgH PHjBr-. 

Phosphine generated by the above procedures is usually contaminated to varying degrees with diphosphine, which renders it spontaneously flammable. Pure phosphine can be produced by hydrolysis of phosphonium iodide [12125-09-6] PH I, which can be made by the action of water on a mixture of phosphoms and diphosphoms tetraiodide [13455-00-0] (71). 

The reaction of higher alkyl chlorides with tin metal at 235°C is not practical because of the thermal decomposition which occurs before the products can be removed from the reaction zone. The reaction temperature necessary for the formation of dimethyl tin dichloride can be lowered considerably by the use of certain catalysts. Quaternary ammonium and phosphonium iodides allow the reaction to proceed in good yield at 150—160°C (109). An improvement in the process involves the use of amine—stannic chloride complexes or mixtures of stannic chloride and a quaternary ammonium or phosphonium compound (110). Use of these catalysts is claimed to yield dimethyl tin dichloride containing less than 0.1 wt % trimethyl tin chloride. Catalyzed direct reactions under pressure are used commercially to manufacture dimethyl tin dichloride. 

The synthesis of phosphonium iodide 24, the precursor of phos-Br phorus ylide 12, begins with the alkylation of 5-lithio-2-methyl- furan,10 derived from the action of n-butyllithium on 2-methylfuran 17 (16), with 1,4-dibromobutane (17) to give 15 in 75% yield (see... 

Scheme 3b). It is instructive at this point to reiterate that the furan nucleus can be used in synthesis as a progenitor for a 1,4-dicarbonyl. Whereas the action of aqueous acid on a furan is known to provide direct access to a 1,4-dicarbonyl compound, exposure of a furan to an alcohol and an acid catalyst should result in the formation of a 1,4-diketal. Indeed, when a solution of intermediate 15 in benzene is treated with excess ethylene glycol, a catalytic amount of / ara-toluenesulfonic acid, and a trace of hydroquinone at reflux, bisethylene ketal 14 is formed in a yield of 71 %. The azeotropic removal of water provides a driving force for the ketalization reaction, and the presence of a trace of hydroquinone suppresses the formation of polymeric material. Through a Finkelstein reaction,14 the action of sodium iodide on primary bromide 14 results in the formation of primary iodide 23, a substance which is then treated, in crude form, with triphenylphosphine to give crystalline phosphonium iodide 24 in a yield of 93 % from 14.

Intermediates 18 and 19 are comparable in complexity and complementary in reactivity. Treatment of a solution of phosphonium iodide 19 in DMSO at 25 °C with several equivalents of sodium hydride produces a deep red phosphorous ylide which couples smoothly with aldehyde 18 to give cis alkene 17 accompanied by 20 % of the undesired trans olefin (see Scheme 6a). This reaction is an example of the familiar Wittig reaction,17 a most powerful carbon-carbon bond forming process in organic synthesis. 

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°. 

At last, barium and calcium complexes of phosphonium bifluorenylide 19 was obtained from the corresponding phosphonium iodide (Scheme 12). The anion displays weak nucleophilicity toward both cations which prefer to coordinate with neutral oxygen of THF and with iodide. Located outside the coordination sphere of the metals, it represents thus the first example of uncomplexed phosphonium diylide [59]. 

In this context, the treatment of the AT-phosphinyl iminoethers 15 with methyl iodide furnish the P-methyl phosphonium iodides, which by heating experience an 0-dealkylation, reminiscent of the Arbuzov reaction, for yielding the iV-acylphosphazenes 16 [45] (Scheme 16). 

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. 

DMII = N,N-dimethyl imidazohum iodide DEII = N,N-diethyl imidazohum iodide BMII = N-butyl-N-methyl imidazohum iodide [Etpy]I = N-ethyl pyridinium iodide [pyMe]I = N-methyl pyridinium iodide MTOPI = methyl trioctyl phosphonium iodide [BusPMe] = methyl tributyl phosphonium iodide. 

Phosphonium iodide See Phosphonium iodide Oxidants See other metal halides, oxidants... 

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. 

Phosphine ignites in cone, nitric acid and addition of warm fuming nitric acid to phosphine causes explosion [1], Phosphonium iodide ignites with nitric acid, and ethylphosphine explodes with fuming acid [2], Tris(iodomercuri)phosphine is violently decomposed by nitric acid or aqua regia [3],... 

See Oxygen, below, also Phosphonium iodide Potassium hydroxide... 

Bromates, chlorates or iodates ignite in contact with phosphonium iodide at ambient temperature if dry, or in presence of acid to generate bromic acid, etc. Ignition also occurs with nitric acid, and reaction with dry silver nitrate is very exothermic. Interaction with antimony pentachloride at ambient temperature proceeds explosively. 

Phosphine, generated by action of the alkali on phosphonium iodide, was shown to... 

In 1985, Cristiau et al. reported that the reaction of methyl 2,3-butadienoate with PPh3 followed by the addition of Nal afforded phosphonium iodide 532, which makes the y-carbon prone to nucleophilic attack, leading to the formation of 4-meth-oxy-2-enonate 533 [197a]. 

PH4I PHOSPHONIUM IODIDE 90.3833 -4.6958E+03 -3.3063E+01 3.5026E-02... 

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... 

Like sulfonyl esters, sulfonamides can be reduced either to sulfinic acids, or to thiols. Heating of p-toluenesulfonamide with fuming hydriodic acid and phosphonium iodide at 100° afforded 85% of p-thiocresol [703]. 

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