Triphenylphosphine, an organic compound with the chemical formula c18h15p, is a white crystalline powder, insoluble in water, slightly soluble in ethanol, soluble in benzene, acetone, carbon tetrachloride, and easily soluble in ether. It is mainly used in organic synthesis. It is the raw material of polymerization initiator and antibiotic drug clindamycin. It is also the standard sample for organic microanalysis and determination of phosphorus.
It will stimulate human body under intense exposure. If it is exposed to neurotoxicity for a long time, it is a dangerous substance and cannot coexist with strong oxidizing agents. The reactivity of aryl phosphines with oxygen is lower than that of benzyl and alkyl phosphines. However, the oxidation of triphenylphosphine by air is very obvious, forming triphenylphosphine oxide. Triphenylphosphine is not easy to ignite and explode, but when it is heated and decomposed, it will produce toxic phosphine and pox smoke. The operation should be carried out in the fume hood.
Synthetic triphenylphosphine: heat the dispersed sodium sand solution at 55~60 degree C, add 0.9 g of dibromotriphenylphosphine under the protection of nitrogen, then drop 3 ml of 46.7 g of chlorobenzene and 19.0 g of phosphorus trichloride mixture, stand for 5 minutes, wait until black appears locally, control the temperature at 35 ± 5 degree C, and drop the rest of the mixture, 1 Finish dripping in 5 hours. Raise the temperature of the reaction solution to 55 plus 5 "C, continue the reaction for 30 minutes, cool and filter, wash the residue with 60ml toluene for 3 times, combine the washing solution and filtrate, concentrate, cool and precipitate white crystals, a total of 33.5g, the yield is 92.4 percent (calculated by PCB), and the purity is Greater than or equal to 99.0 percent (GC method).
Use of triphenylphosphine:
1. It is used as raw material for organic synthesis, polymerization initiator, antibiotic drug clindamycin, and standard sample for organic microanalysis and determination of phosphorus.
2. Preparation of palladium, iridium, rhodium, nickel and other complex catalysts, wfttig reagent, triphenylphosphine dihalide deoxygenation (N-pyridine oxide, nitroso benzene, hydroperoxide), desulfurization and debromination reagents. Make a-bromonitro compound produce nitrile. Reaction with fatty diazo compounds to synthesize a_ Ketone aldehyde Monoketoacid. Beckmann rearrangement. Dequaternization of pyridinium salt. It is used in some synthesis together with bromine iodine, carbon tetrachloride (bromine), n-brominated butadiene imine, etc.
3. Triphenylphosphine is a quite common reductant. In most cases, the reaction is driven by the formation of triphenylphosphine oxide (a thermodynamically favorable reaction). In addition, triphenylphosphine is widely used as a ligand for metal catalysts.
Deoxidizing agent. Photodelaying reagent. Azide reductant: it can reduce organic azide to amine by combining with water.
RN3 plus PH3p plus H2O = RNH2 plus PH3PO plus N2
alkynate diene reaction catalyst: , - Alkynate is rearranged into conjugated diene ester (sorbate) under the catalysis of triphenylphosphine: phosphorus ylide used in the synthesis of Wittig reaction:
H3P plus CH3Br → PH3P-CH3Br - (dry ether, Phli) → PH3P-CH2P
Deoxygenation triphenylphosphine is widely used in the reduction of hydrogen peroxide or endoperoxide. The reaction is related to the substrate and can produce alcohols, carbonyl compounds or epoxides. The main driving force of this kind of reaction is that triphenylphosphine can form a strong p=o bond with a relatively weak O-O bond (188~209 kj/mol). For example, triphenylphosphine can be used to reduce and decompose odorous oxides and selectively prepare ketones and aldehydes
Reaction with azides triphenylphosphine reacts with organic azides to form imino phosphine
Imino phosphine is a relatively active nucleophile, which is easy to react with electrophiles. For example, it reacts with aldehydes and ketones to form imines and triphenylphosphine oxides. This reaction is similar to Wittig reaction, which is called aza Wittig reaction. The driving force of this reaction is also due to the formation of triphenylphosphine oxide
Reaction with organic sulfide triphenylphosphine can convert cyclic sulfur compounds to olefins at room temperature
Dehalogenation reaction - Brominated ketones react with triphenylphosphine to form ketones
The reaction with organic epoxides is refluxed in water and acetone solvent, and triphenylphosphine can convert epoxy compounds into cycloimines with the participation of sodium azide
Preparation of substituted pyrrole aniline and furan Dione react with triphenylphosphine to produce 1-phenyl-2,5-pyrrolidone
As a ligand of metal catalyst, it forms a metal catalyst with many transition metals as a ligand. For example, Pd (PPh3) 4 is an important catalyst, which is often used in catalytic coupling reactions. It is an important method to build carbon carbon bonds. Its characteristic is that the catalytic conditions are mild. For example, under the joint action of PD (PPh3) 4 and Ag2O, phenylboric acid reacts directly with aromatic halogenated hydrocarbons to produce biphenyl compounds, and the yield of this reaction reaches 90 percent
In addition to phenylboric acid and halogenated compounds, magnesium reagents, zinc reagents, tin reagents, silicon compounds, etc. can be used as substrates for coupling reactions.
4. It is widely used in pharmaceutical, petrochemical, coating, rubber and other industries as catalyst, accelerator, flame retardant, and analytical reagent.
5. In pesticides, trimethyl phosphite, an intermediate of organophosphorus, can be synthesized by transesterification, and then a series of organophosphorus pesticides such as dichlorvos, monocrotophos, phosphorylamine can be obtained. In addition, it can be used as a stabilizer for synthetic rubber and resin, an antioxidant for PVC, and a raw material for the synthesis of alkyd resin and polyester resin.