Sodium hypophosphite reduction

Electroless Nickel Nickel is deposited through chemical (sodium hypophosphite) reduction. Rate control, by pH and temperature, determines phosphorous content, usually 8-11% by weight. 10-20... 

Zhu, H.-T, Zhang, C.-Y., and Yin, Y.-S. (2004) Rapid synthesis of copper nanoparticles by sodium hypophosphite reduction in ethylene glycol under microwave irradiation,/ Cryst Growth, 270(3-4), 722-728. 

Triethylammonium formate is another reducing agent for q, /3-unsaturated carbonyl compounds. Pd on carbon is better catalyst than Pd-phosphine complex, and citral (49) is reduced to citronellal (50) smoothly[55]. However, the trisubstituted butenolide 60 is reduced to the saturated lactone with potassium formate using Pd(OAc)2. Triethylammonium formate is not effective. Enones are also reduced with potassium formate[56]. Sodium hypophosphite (61) is used for the reduction of double bonds catalyzed by Pd on charcoal[57]. 

Distibines and Distibenes. A considerable number of tetraalkyl- and tetraaryldistibines have been investigated. These are usually obtained by the reduction of a dialkyl- or diaryUialostibine with sodium hypophosphite (111,112) or magnesium (108,116). Distibines can also be prepared by the treatment of a metal dialkyl- or diarylstibide with a 1,2-dihaloethane (70,71,77,85,91,128)... 

In the alternative method of reduction, which is particularly valuable for the determination of small amounts of tellurium, the procedure is as follows. Treat the solution containing, say, up to about 0.01 g Te in 90 mL with 10 mL of 1 3-sulphuric acid, then add 10 g sodium hypophosphite (phosphinate), and heat on a steam bath for 3 hours. Collect and weigh the precipitated tellurium as above. 

This reduction has also been achieved by treating the nitrile with sodium hypophosphite (NaH2P02 ) and Raney nickel in aqueous acetic acid - pyridine or formic acid. 

Pure arsenic has been prepared by reducing carefully purified ammonium dihydrogen arsenate at 1000° C. in a current of ammonia, the arsenic being finally resublimed in a vacuum.7 The element may also be obtained as an amorphous precipitate by reduction of aqueous arsenious acid, for example, by means of sodium hypophosphite,8 or by the addition of a few drops of phosphorus trichloride.9 The reaction in the latter case probably takes the following course ... 

Rapid reduction of aromatic nitro compounds into amines has been described using sodium hypophosphite and FeSC>4-7H20. The reactions showed best results in terms of yields and purity, when the substrates were pre-absorbed on alumina and irradiated by microwaves under solvent-free conditions. The reaction is chemoselective and does not affect functional groups such as CN, OH, COOH, CONH2 or halogens. In addition, oximes were not reduced under the given reaction conditions, but were dehydrated to the corresponding nitriles instead (Scheme 4.32)57. 

Meshram, H.M., Ganesh, Y.S.S., Sekhar, K.C. and Yadav, J.S., Microwave thermolysis VII selective diversity in the reduction using sodium hypophosphite under microwave irradiation, Synlett, 2000, 993-994. 

Reduction of nitroalkenes. Vinyl nitro compounds are reduced to saturated ketones or aldehydes by Raney nickel and an aqueous solution of sodium hypophosphite. Ester groups, C=C bonds, and aryl NO, and halo groups are not reduced. Under these conditions nitroalkanes arc reduced to amines, and oximes are converted into carbonyl compounds in high yield. 

In the reduction of p-chlorocinnamic acid with an excess of sodium hypophosphite and palladium (equation 47), the double bond is saturated and the hydrogenolysis of chlorine occurs. With one equivalent of the hypophosphite, only saturation of the double bond takes place, and p-chlorohydrocinnamic acid is obtained after 1.5 h. ... 

The preceding arsinic acid (5 grams), in 50 c.c. of water and 10 c.c. of concentrated hydrochloric acid, is reduced with 7 to 10 grams of sodium hypophosphite and 8 c.c. of a one per cent, solution of potassium iodide by warming the mixture on the water-batli and passing in a stream of carbon dioxide. The reduction product separates, is filtered off,washed with dilute hydrochloric acid, and dried at 50° C. in a vacuum. The yield is 80 per cent. The arseno-compound is a yellowish-red, amorphous powder, soluble in water and in small quantities in methyl alcohol, from which it may be precipitated by absolute alcohol. In acids and alkalis it is insoluble. 

Symmetrical arsenobenzenes are formed by reduction of the following compounds with sodium hypophosphite in the i)resem e of hytlriodie acid 3-Chloro-4-hydroxy-5-acetamidojjhcnylarsinie acul, 2-ehloro- t-... 

Polychlorobenzenes in the presence of a Pd/C catalysts can be debalogenated with sodium hypophosphite [49] or hydrogen [50, 51] in a multiphase system (eq. (3)). 1,2,4,5-Tetrachlorobenzene gives a quantitative yield of benzene using H2 or NaH2P02 as reductant. 

P-Ketoesters. /3,y-Unsaturated )3-nitro esters undergo reductive Nef reaction in the presence of Raney nickel and sodium hypophosphite in a buffered medium. 

Electroless coatings form by the reduction of nickel ions by hypophosphite (usually monobasic sodium hypophosphite, NaH2P02>. The treating solution contains an excess of nickel. Rates of precipitation depend on temperature and pH, and control of these variables allows control of the properties of the coating, in particular its phosphorus content [144]. The oxidized phosphorus compound releases hydrogen ions, which tend to reduce the pH of the solution. The formulation therefore usually contains acetate or citrate buffers. 

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