Sodium hypophosphite

About: Sodium hypophosphite is a research topic. Over the lifetime, 1695 publications have been published within this topic receiving 15932 citations.

Ft-Ir and Ft-Raman Spectroscopy Study of the Cyclic Anhydride Intermediates for the Esterification of Cellulose: Ii. Formation of Anhydrides Catalyzed By Sodium Hypophosphite

Abstract: A five-membered cyclic anhydride is the reactive intermediate of polycarboxylic acids for esterifying cellulose. In our previous research, we found that polycarboxylic acids in a crystalline state start to form 5-membered cyclic carboxylic anhydrides when the temperature reaches the vicinity of their melting points, and that hydrogen bonding between carboxylic acid groups prevents the formation of the cyclic anhydride intermediates at lower temperatures. In this research, we studied the formation of cyclic anhydride intermediates by 1,2,3,4-butane-tetracarboxylic acid (BTCA) and itaconic acid (IA) in the presence of sodium hypophosphite (NaH 2 PO 2 ) ' We found that NaH 2 PO 2 weakens the hydrogen bonding between the carboxylic acid groups of BTCA. In the presence of NaH 2 PO 2 , BTCA forms the cyclic anhydride at temperatures significantly lower than its melting point. NaH 2 PO 2 also reduces the temperatures required for the formation of the anhydride intermediate of IA on cotton fabric. The catalysis for the formation of anhydride intermediates by NaH 2 PO 2 contributes to the acceleration of esterification of cotton cellulose by polycarboxylic acids.

Process for the preparation of alkyl glycosides and alkyl oligoglycosides

Abstract: Alkyl glycosides and alkyl polyglycosides are prepared by reacting saccharides and alcohols having 12 to 20 C atoms by acid catalysis in the presence of sodium hypophosphite and up to 1.3% by water, relative to the total of saccharides and alcohols, the molar ratio of saccharide to alcohol ranging from 1:5 to 1:10; and, after reaction is complete, neutralizing the reaction medium with an alkali metal hydroxide dissolved in an alcohol having 1 to 4 C atoms.

Process for coating fibrous glass with amorphous nickel phosphorous glass metal

Abstract: The invention relates to a process for coating fibrous glass with a glass metal mainly consisting of nickel-phosphorus, under conditions free of current. According to the process a fibrous glass substrate is treated with an aliphatic alcohol having 1 to 4 carbon atoms and subsequently with an aqueous solution of SnCl 2 , in the presence of hydrochloric acid, and is then activated with a solution of palladium chloride in aqueous hydrochloric acid. Thereafter the pretreated and activated substrate is kept in a bath comprising nickel ammonium sulfate or nickel sulfate and nickel ammonium sulfate as a nickel-containing component, in combination with sodium hypophosphite, an alkali metal salt of at least one organic acid having a low molecular weight, a mineral acid, preferably sulfuric acid or hydrochloric acid in an amount sufficient to adjust the pH to 3 to 4, and optionally organic or inorganic metal-deposition regulating agent(s) at a temperature between 50° to 90° C.

Hydrogen incorporation in Ni–P films prepared by electroless deposition

Abstract: Electroless NiP films, with 12 to 16 wt % P, were deposited from a moderately acid solution. Thermogravimetric analysis indicates the presence of occluded hydrogen in the layers, which desorbs upon heating. The amount of incorporated hydrogen decreases when the pH of the solution or the nickel sulfate concentration is increased; by contrast it increases with hypophosphite concentration. Cyclic voltammetry, using an electrochemical quartz crystal microbalance, confirms the existence of parasitic reactions, namely the reduction of protons of the solvent during the cathodic process and oxidation of hydrogen during the dissolution of the layers. This behaviour is in qualitative agreement with the proposed reaction scheme.