Patent GB-786758-A (GB)
Title: New quaternary ammonium pyrophosphate compounds
Inventor: SEMMENS PETER WILLIAM BRETT
IPC: C01B25/42
Filed: 1955-02-23
Abstract: The invention comprises quaternary ammonium pyrophosphate compounds in which each quaternary ammonium group has the four nitrogen covalencies attached to organic groups at least one of which is or contains an alkyl radical having 6 or more carbon atoms, said compounds having the formula X2Y2P2O7 in which Y is a quaternary ammonium group and X is hydrogen or a quaternary ammonium group which may or may not be the same group as Y.  The compounds may be obtained by the following general method: A column of a strongly basic anion exchange resin is activated in the hydroxide form by contact with an aqueous solution of a water-soluble hydroxide, e.g. sodium hydroxide. An aqueous solution of any water-soluble quaternary ammonium salt (e.g. the bromide) containing the appropriate quaternary ammonium group is repeatedly passed through the column until the anion is not detectable in the drainings and the resulting solution of quaternary ammonium hydroxide is treated with an aqueous solution of pyrophosphoric acid until the pH is 4.5.  The mixture is then evaporated to dryness under vacuum and the diquaternary ammonium pyrophosphate product may be dried over phosphoric oxide in a vacuum desiccator.  If the tetra-quaternary ammonium pyrophosphate is required, the same procedure is adopted except that the pH is adjusted to 8.5.  When compounds in which X and Y in the above general formula are different groups are to be prepared, a solution of the compound X2H2P2O7 is first prepared by the above method and this is then treated with a solution of the quaternary ammonium hydroxide YOH, wherein Y is different from X until the pH is 8.5 and the solid compound X2Y2P2O7 is obtained by evaporation.  Specified quaternary ammonium groups are cetyl trimethyl ammonium, didecyl dimethyl ammonium, cetyl pyridinium, tetradecyl pyridinium, lauryl benzyl dimethyl ammonium, 2-(p-tert.-octyl phenoxy) ethyl benzyl diethyl ammonium, di-n-octyl dimethyl ammonium and stearyl benzyl dimethyl ammonium.  Examples are given for the production of di-(cetyl trimethyl ammonium) dihydrogen pyrophosphate and tetra-(cetyl trimethyl ammonium) pyrophosphate using the above general method.  An example is also given to illustrate an alternative method of preparing the tetra-pyrophosphate salts. In this case an anion exchange resin is activated by contact in a column with an aqueous solution containing tetra-sodium pyrophosphate and then washed with water until the washings give a pH of 7-8.  A solution of cetyl trimethyl ammonium hydroxide (prepared by passing the corresponding bromide through a column of anion exchange resin activated by contact with an aqueous solution of sodium hydroxide) is adjusted to a pH of 7.0 with an aqueous normal solution of sulphuric acid and the resultant solution is then passed repeatedly down the column of ion exchange resin, which has been activated with the sodium pyrophosphate solution, until the drainings are free from sulphate ion and the collected drainings are then evaporated under reduced pressure and dried over phosphoric acid.  The products are stated to be suitable for use as boundary lubricants (see Group III).ALSO:A composition suitable for use as a boundary lubricant comprises one or more quaternary ammonium pyrophosphate compounds (as defined below) and one or more suitable liquid or solid vehicles in which the pyrophosphate compound or compounds may be dissolved or dispersed.  The quarternary ammonium pyrophosphate compounds are compounds in which each quaternary ammonium group has the four nitrogen covalencies attached to organic groups at least one of which is or contains an alkyl radical having 6 or more carbon atoms and have the formula X2Y2P2O, in which Y is a quaternary ammonium group and X is hydrogen or a quaternary ammonium group which may or may not be the same group as Y (see Group IV (b)).  Specified quaternary ammonium groups are cetyl trimethyl-, didecyl (or di-n-octyl) dimethyl-, lauryl benzyl dimethyl-, stearyl benzyl dimethyl-, and 2-(p-tert. octyl phenoxy) ethyl benzyl diethyl-ammonium, cetyl pyridinium, and tetradecyl pyridinium.  Specified vehicles in which the pyrophosphates may be dissolved or dispersed are hydrocarbons, mineral oils, vegetable oils such as castor oil, siloxane oils, aliphatic esters, alkylene glycols, petroleum jelly, animal fats, vegetable and mineral grease-like substances, solid siloxane compounds and fatty acids and their soaps and esters.  Specified quaternary ammonium compounds are di-(cetyl trimethyl ammonium) dihydrogen pyrophosphate and tetra aetyl trimethyl ammonium) pyrophosphate.