Europaisches Patentamt J» European Patent Office 00 Publication number: 0 256 832 Office europeen des brevets A2 EUROPEAN PATENT APPLICATION (jy Application number: 87307077.5 © IntCI.3: C 01 F 7/56 @ Dateoffiling: 10.08.87 (30) Priority: 11.08.86 GB 8619552 ) Applicant: UNILEVER PLC Unilever House Blackf riars P.O. Box 68 London EC4P4BQ(GB) (g) Date of publication of application: 24.02.88 Bulletin 88/8 ) Designated Contracting States: GB @ Designated Contracting States: AT BE CH DE ES FR GB GR IT LI NL SE ) Applicant: UNILEVER NV Burgemeesters'Jacobplein 1 P.O. Box 760 NL-3000 DK Rotterdam(NL) I Designated Contracting States: BE CH DE ES FR GR IT LI NL SE AT I Inventor: Inward, Peter William High Close Wetstone Lane West Kirby Wirral Merseyside L48 7HG(GB) Representative: Doucy, Robert Henry et al, Unilever PLC Patents Division P.O. Box 68 Unilever House London EC4P4BQ(GB) (54) Preparation of basic aluminium halides. © The disclosure concerns a process forthe manufacture of basic aluminium halides in powder form which have an aluminium:halide molar ratio of 1.7:1 to 2.2:1 and contain more than 20% of the aluminium in the Band HI fraction as determined by a chromatographic procedure. The disclosure centres on the finding of reaction conditions for the known interaction between aluminium and aluminium halides which lead directly to a solution of a basic aluminium halide having more than 20% of the aluminium in the Band III fraction. N The temperature of reaction is 50° to 105°C and the final alumi- < nium concentration of the solution is 0.8% to 6.75%. The sol- ution is dried, preferably spray dried or freeze dried, to give CM the powder. The preparation of powders CO having at least 20% of the aluminium contained in Al,304o species is also descri- 00 bed. CD 10 N Q. LU Croydon Printing Company Ltd. ©256832 - 1 - J.3045 PREPARATION OF BASIC ALUMINIUM HALIDES 5 This invention relates to the preparation of basic aluminium halides, more particularly to the preparation of a basic aluminium chloride or bromide having good antiperspirant activity. 10 Basic aluminium chlorides and to a lesser extent bromides have been available commercially for many years both in the form of aqueous solutions and in the form of hydrated powders. One well known application of these products is 15 as the active ingredient of antiperspirant products. For such application the basic aluminium chlorides especially are commercially available in varying degrees of basicity, which can be expressed in terms of the aluminium to chlorine ratio which generally ranges from about 2:1 to 20 about 0.9:1. The products available commercially in the form of aqueous solutions generally have an aluminium concentration of about 12% by weight. The powdered forms of the basic aluminium chlorides and bromides are J> 3040256832 - 2 - j. solutions of frequently obtained by spray-drying aqueous solutions are usually made by these basic halides. These solution of dissolving aluminium metal in an aqueous elevated temperature aluminium chloride or bromide at an in US-A-2 196 016 (Huehn et 5 and such method is described Australian Drug al) and AU-A-150,410 (Elliotts & of aluminium metal Proprietary Ltd) . The amount to a final dissolved is controlled so as to correspond aluminium to halide ratio. product having the desired the aluminium halide 10 Furthermore, the concentration of final having an solution is chosen so as to give a product weight which is aluminium concentration of around 12% by sale or for conversion to most advantageous for commercial drying such solutions. a powdered form, eg. by spray 15 al) the disclosure of in US-A-4 359 456 (Gosling et , there is which is incorporated herein by reference, commercially available described a process for making from bromide having materials a basic aluminium chloride or The described 20 enhanced antiperspirant efficacy. process first forming a solution of by the prior patent involves aluminium the basic aluminium halide having an This can be concentration of 2.5 to 8.5% by weight. commercially available prepared by dissolving in water a halide (as in Example 2) or by 25 powder of a basic aluminium available solution of a diluting with water a commercially The solution basic aluminium halide (as in Example 9) . 50° to 140°C so as to is then heated at a temperature of species within modify the distribution of the polymeric the modified basic 30 such solution in such manner that at least aluminium halide has at least 20%, preferably in the Band III fraction 25%, of the aluminium contained analytical procedure as determined by a chromatographic obtained having described in the patent. The products in the Band III fraction 35 such high contents of aluminium Powdered forms of have superior antiperspirant activity. J> - 3 - j.304©256832 the basic improved aluminium halides are obtained by drying the heat-treated solutions. In our copending European Patent Application No. 5 86 300916.3 (Publication No. 0191 628), we have described a simplified process for making a powder of a basic aluminium chloride or bromide having a high proportion of the aluminium in the Band III fraction without the need to heat-treat a pre-formed solution of a basic aluminium 10 halide. By the process described in this previous application basic a aluminium halide having a high content of aluminium in the Band III fraction is prepared directly, the process comprising the steps of:- 15 a> dissolving metallic aluminium in an aqueous starting solution of an aluminium compound selected from aluminium chloride and aluminium bromide, said starting solution being held at a temperature of about 50 °C to about 105°C, 20 preferably 50 °C to 95 °C, for a time just long enough to dissolve sufficient aluminium to produce an aqueous solution of a final basic aluminium halide having an aluminium: halide molar ratio in the range 1.7:1 to 2.2:1, the 25 concentration of the aluminium in the starting solution and the amount of aluminium dissolved being such that the aluminium concentration in the solution of the final basic aluminium halide is from 0.8% to 6.75% by weight and said final 30 basic aluminium halide having at least 20% of the aluminium contained in the Band III fraction; and b) drying the solution of the final basic 35 aluminium halide so as to give the final basic - 4 - j.3045 0256832 aluminium halide in the form of an hydrated powder having at least 20% of the aluminium contained in the Band III fraction. 5 The present invention also has as an object the direct preparation of a final basic aluminium halide having an aluminium: halide molar ratio in the range 1.7:1 to 2.2:1 and having a high content of aluminium in the Band III fraction. The present invention is based on our 10 appreciation that such products can be produced by a procedure similar to that described in our previous application but starting from a basic aluminium halide such as an aluminium dichlorhydrate or aluminium sesquichlorhydrate . 15 According to the invention there is provided a process of making a basic aluminium halide having an aluminium: halogen molar ratio of from 1.7 to 2.2 : 1 and having at least 20% of the aluminium contained in the Band 20 III fraction which process comprises the steps of :- a) dissolving metallic aluminium in an aqueous starting solution of a basic aluminium halide selected from basic aluminium chlorides and 25 basic aluminium bromides having an Alrhalide molar ratio up to 1.8:1, preferably in the range 0.9:1 to 1.5:1, said starting solution being held at a temperature of about 50 °C to about 105°C, preferably 50°C to 95°C, for a time just 30 long enough to dissolve sufficient aluminium to produce an aqueous solution of a final basic aluminium halide having an aluminium: halide molar ratio which exceeds by at least about 0.3 that of the starting basic aluminium halide and 35 is in the range 1.7:1 to 2.2:1, the concentration of the aluminium in the starting - 5 - j. 304^)256832 solution and the amount of aluminium dissolved being such that the aluminium concentration in the solution of the final basic aluminium halide is from 0.8% to 6.75% by weight and said final 5 basic aluminium halide having at least 20% preferably at least 25%, of the aluminium contained in the Band III fraction; and optionally 10 b> drying the solution of the final basic aluminium halide so as to give the final basic aluminium halide in the form of an hydrated powder having at least 20%, preferably at least 25%, of the aluminium contained in the Band III 15 fraction. Characterisation of materials containing species differing in size by means of size exclusion chromatography is generally known. The size exclusion chromatographic 20 procedures for characterising the basic aluminium compounds of this invention will now be described. The analytical procedure is performed on a stainless steel column of dimensions 25 to 30 cm high and of 7 mm internal 25 diameter packed with porous silica of nominal particle size 5 microns and pore size of 60 Angstroms, which silica has been deactivated by silylation to eliminate adsorption and unwanted ionic effects in size exclusion separations. A suitable silica is that available commercially as 30 LiChrosorb RP-2. The silica employed by the Applicants in deriving analytical data given herein had a cumulative undersize particle size distribution by weight of 10% less than 5 microns, 50% less than 6 microns and 90% less than 7 microns.