Patent GB-1026366-A (GB)
Title: Substituted methylenediphosphonic acid compounds and detergent compositions containing them
IPC: C11D3/00
Filed: 1964-03-18
Abstract: Built detergent compositions comprise (a) an organic surfactant and (b) a builder of formula <FORM:1026366/C4-C5/1> where X and Y are each hydrogen or a methyl, benzyl, halogen or carboxymethyl radical, at least one of them being other than H, or a water-soluble salt thereof (see Division C2), the weight ratio of (b) to (a) being from 1:3 to 10:1, and the compositions having a pH of 8-12.  Any conventional surfactant may be used, e.g. anionic (soaps, sulphates and sulphonates), non-ionic (e.g. of polyethenoxy type), amine and phosphine oxides, ampholytic and zwitterionic.  These are extensively exemplified, but those actually used in examples are sodium dodecylbenzene sulphonate, a mixture of hexadecyl and octadecyl-2-hydroxy thiosulphates, a mixture of condensates of ethylene oxide with a propylene glycol/propylene oxide condensate, a dodecyl phenol/ethylene oxide (12) condensate, dimethyldodecylamine oxide, 3 - (N,N - dimethyl - N - coconut ammonio) -2-hydroxy-propane-1-sulphonate, and 3 - (N,N - dimethyl - N-hexadecyl ammonio)-propane- 1 - sulphonate. Optional additives mentioned include alkali metal bonates, carbonates, sulphates, phosphates and silicates, KOH, NaOH, sodium carboxymethyl cellulose, sodium carboxymethyl hydroxyethyl cellulose, tarnish inhibitors (e.g. benzothiazole and ethylenethiourea), hydrogenated marine oil fatty acid and alkali metal benzene, toluene and xylene sulphonates.  The compositions may be formulated in granular, flake, tablet or liquid form, and in the latter case the vehicle may be water or a water/alcohol mixture.ALSO:The invention comprises substituted methylene diphosphonic acids having the general formula <FORM:1026366/C2/1> wherein X and Y each represent bromine, fluorine, a benzyl radical, a carboxymethylene radical or hydrogen, at least one of X and Y being other than hydrogen, or a salt thereof. They may be obtained by an oxidation-reduction reaction at low temperature, e.g. 0 DEG  to 35 DEG  C. between a metallating agent such as sodium, potassium, sodium hydride or potassium-sodium eutectic alloy, and a tetraalkyl ester of methylene diphosphonic acid and then reacting the carbanion produced in this step with a suitable alkylating agent or halogenating agent to give a substituted methylene diphosphonate tetraalkyl ester, which may be hydrolysed with hydrochloric acid to the free phosphonic acid or in the case of isopropyl esters pyrolysed to the acid and then converted to the corresponding salts with the addition of base. Analogous compounds in which X and Y may each be a halogen, e.g. chlorine or a methyl radical are prepared similarly. Examples are given for the preparation of the following diphosphonic acids, their tetraisoproyl esters and their sodium salts (1) ethylidene diphosphonic acid, (2) isopropylidene diphosphonic acid, (3) benzyl-methylene diphosphonic acid, (4) bromoethylene diphosphonic acid, (5) dichloromethylene diphosphonic acid, (6) dibromomethylene diphosphonic acid and (7) 2-carboxy-ethylidene diphosphonic acid and 2-carbethoxy ethylidene diphosphonic acid tetraisopropyl ester.  The compounds may be used as detergency builder compounds (see Division C5).  The tetraalkyl ester of methylene diphosphonic acid used as a starting material may be prepared by refluxing triisopropyl phosphite with dibromomethane and allowing the isopropyl bromide by-product to distil off.