Classifications

• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D3/00—Other compounding ingredients of detergent compositions covered in group C11D1/00
  • C11D3/39—Organic or inorganic per-compounds
  • C11D3/3902—Organic or inorganic per-compounds combined with specific additives
  • C11D3/3937—Stabilising agents
  • C11D3/394—Organic compounds
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D3/00—Other compounding ingredients of detergent compositions covered in group C11D1/00
  • C11D3/39—Organic or inorganic per-compounds
  • C11D3/3902—Organic or inorganic per-compounds combined with specific additives
  • C11D3/3937—Stabilising agents
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D3/00—Other compounding ingredients of detergent compositions covered in group C11D1/00
  • C11D3/39—Organic or inorganic per-compounds
  • C11D3/3945—Organic per-compounds

Definitions

• This invention is concerned with organic peroxyacids and their manufacture.
• the invention is particularly con ⁇ cerned with the stability of said organic peroxyacids.
• Organic peroxyacids are able to function as bleaching agents in a detergent composition.
• Organic peroxyacids which have been proposed for such use include peroxybenzoic acid, peroxyphthalic acid, isomers and substituted derivatives thereof, peroxyalkanoic acids and diperoxyalkanedioic acids such as diperoxyazelaic acid and diperoxydodecanedioic acid. Discussion of such acids can be found in US Patents 4,100,095, 4,170,453 and 4,325,828 as well as numerous other documents.
• Another series of acids which have been proposed are phthalimido substituted peroxyalkanoic acids disclosed in EP-A-325288.
• WO 90/07501 (Interox) describes the variation in stability of peroxyacids according to features of their structure. This document teaches that phthalimido peroxyacetic acid is somewhat explosive whereas longer chain ho ologues are relatively more stable.
• transition metal ions can catalyse unwanted decomposition of peroxyacid compounds and it has, therefore, been proposed to mix peroxyacid com- pounds with chelating agents to enhance storage stability of organic peroxyacid-containing compositions and/or stabilise the wash liquor against unwanted decomposition of the peroxyacid.
• chelating agents are disclosed in US Patents 4,170,453 and 4,100,095. This disclosure is also reviewed in EP-349220.
• organic peroxyacids may be incorporated into compositions which contain only a minority proportion of peroxyacid and which also contain a chelating agent for sequestering transition metal ions, this chelating agent being incorporated for the purpose of promoting storage stability of the peroxyacid and/or stability of the peroxyacid in a wash liquor during use.
• a chelating agent for sequestering transition metal ions such as sodium citrate
• European published application 349220 is concerned with amidoperoxyacids which contain an amide link in a hydrocar ⁇ bon chain.
• This Patent teaches that the storage stability of these peracids can be improved considerably by washing the peracids with phosphate buffer and leaving some phosphate in contact with the peracid after washing.
• the amidoperoxyacids are acid sensitive and this beneficial effect of phosphate buffer is prin ⁇ cipally attributed to neutralisation of residual strong acid left from the reaction in which the amido peroxyacid is prepared.
• the phosphates which are used may be or- thophosphates or pyrophosphates or a mixture of the two. Such phosphates have the ability to sequester transition metal ions.
• the present invention provides the use of a binding agent for transition metal ions to enhance stability of a substantially water-in ⁇ soluble organic peroxyacid against exothermic decomposition initiated by heat.
• this invention provides a composition
• a composition comprising from 80 to 99.9% by weight of a substantially water-insoluble organic peroxyacid mixed with from 0.1 to 20% by weight of a binding agent for transition metal ions, which binding agent and peroxyacid are stable in the presence of each other, with the proviso that the peroxyacid does not includes an amide linkage.
• DSC differential scanning calorimetry
• bringing an organic peroxyacid into contact with a binding agent in accordance with this invention leads to a composition in which the temperature of thermal decomposition has increased.
• the decomposition may also occur over a temperature range of different width.
• differential scanning calorimetry may show an increase in the temperature at which maximum decomposition occurs and/or an increase in the temperature at which decomposition begins. The outcome of a DSC measurement will show these results as a shift in the position of a peak, or as a shift in the base of the peak at its lower temperature side, respec ⁇ tively.
• One possibility is simply dry-mixing the two materials in solid form to obtain a mixture containing from 80 to 99.9% by weight of the peroxyacid.
• Another possibility is to wash a substantially water-in- soluble peroxyacid with a solution or suspension of the binding agent and leave from 0.3 to 3% by weight, preferably from 1 to 2% by weight, more preferably from 1 to 1.5% by weight, of the binding agent, as calculated on the total weight of peroxyacid and binding agent, in con- tact with the peroxyacid.
• the final pH of the thus obtained material is in the range of from 3.5-6.0, more preferably of from 4-5.
• a third aspect of this invention provides a process for enhancing the thermal stability of a substantially water-insoluble organic peroxyacid which does not include any amide linkage, comprising washing the peroxyacid with an aqueous solution or suspension of a binding agent for transition metal ions under conditions such that from 0.3 to 1.3% by weight of the binding agent, as calculated on the total weight of binding agent and peroxyacid, remains in contact with the peroxyacid and a final pH of from 3.5- 6. 0 is obtained .
• a preferred possibility is to precipitate the organic peroxyacid in the presence of the binding agent, such that 0.3-3% by weight, preferably 1-2% by weight, more preferably 1-1.5% by weight of the binding agent, as cal ⁇ culated on the total weight of peroxyacid and binding agent, remains in contact with the peroxy acid.
• the final pH of the thus-obtained material is in the range of from 3.5-6, preferably from 4-5. This leads to a beneficial enhancement of stability, and moreover it is then possible to -wash the peroxyacid further without losing the enhanced stability.
• a composition obtained in this way is more robust than compositions obtained in other ways.
• a fourth aspect of this invention provides a process for enhancing the stability of a substantially water-insoluble organic peroxyacid which comprises precipitating the peroxyacid in the presence of a binding agent for transition metal ions such that 0.3 - 3.0% by weight of the binding agent, as calculated on the total weight of binding agent and peroxyacid, remains in contact with the peroxyacid and a final ph of from 3.5 - 6.0 is obtained.
• This preferred process can be carried out as a step in the conventional procedure by which a peroxyacid is made. This procedure consists of oxidising the appropriate carboxylic acid with hydrogen peroxide in a strong acid medium, and then quenching the reaction. Conventionally this quenching has been done by running the reaction mixture into ice and water. In order to implement the preferred process of the invention the reaction mixture is run into an aqueous solution containing a precursor for the binding agent.
• Another, possible way to implement this invention is to dissolve the peroxyacid in an organic solvent, (dichloromethane for instance) and wash the solution with an aqueous solution of the binding agent before separating the peroxyacid from the organic solvent.
• a suitable a- queous solution of binding agent would be phosphate buffer at about pH 4.
• Yet another way to use a binding agent to enhance the stability of an organic peroxyacid is to bring the binding agent into contact with an organic acid and then use the resulting acid as the starting material for making the corresponding peroxyacid.
• a process for enhancing the stability of an organic peroxyacid may comprise either
• step (ii) precipitating the corresponding acid in the presence of a said binding agent for transition metal ions, and then (iii) oxidising the acid from step (i) or step (ii) to the peroxyacid.
• a particulate composition is effectively obtained, said composition comprising particles of the organic peroxyacid with the binding agent trapped in said par ⁇ ticles.
• the binding agent is the binding agent
• Suitable binding agents should not react to any substantial extent with the peroxyacid, under conditions to which they are exposed.
• ethylene diamine tetraacetic acid is oxidised by peroxyacids in solution and so would not be suitable, except for use by mixing with dry solid peroxyacid.
• the binding agent may possibly form an insoluble salt with at least one transition metal or may function by forming a co-ordination complex with at least one transition metal ion. Thirdly the binding agent may bind to transition metal sites in impurity particles present in colloidal suspension.
• a binding agent should have good affinity for one or more transition metal ions, e.g. for ferric ion which is a likely trace contaminant.
• the affinity of a complexing agent L for a metal ion M can be expressed by the equilibrium constant for the complex forming reaction nL + M — ML,
• [ML n ] [L] and [M] are the concentrations of the co ⁇ ordination complex, the free complexing agent and the free metal ion in aqueous solution under specified conditions of temperature and ionic strength, e.g. 25°C and zero ionic strength.
• Such an equilibrium constant is also referred to as the stability constant for the complex. It may be the overall equilibrium constant for the formation of a complex through several steps in sequence, or the equilibrium constant for a single step reaction.
• a binding agent which forms a co-or ⁇ dination complex should preferably form a complex with at least one transition metal ion with a stability constant K of at least 10 6 in aqueous solution at 25°C and at zero ionic strength.
• a complexing agent forms such a co-ordination complex with at least one transition metal ion, significant examples of which are the ions of iron, manganese, cobalt, nickel, zinc and copper. More preferably the complexing agent forms such a complex with at least Fe 3+ .
• Binding agents for transition metals which are suitable for the present invention include dihydrogen orthophosphate, pyrophosphate, polyacrylate, titanium chloride, stannic salts, and stannous salts.
• the effectiveness and hence the suitability of a binding agent can be assessed by differen ⁇ tial scanning calorimetry as mentioned further below.
• the preferred binding agent is dihydrogen orthophosphate.
• the present invention is applicable to substantially water- insoluble organic peroxyacids, having a solubility between 0.1 and 5 mmol in water at ambient temperatures and a pH of from 3.5-6. As indicated above, a wide variety of such acids are known.
• Peroxyacids which are particularly envisaged include phthalimido-substituted peroxyalkanoic acids of formula
• R is an arylene or alkylene group of up to 10 carbon atoms, notably alkylene of 2 to 7 carbon atoms.
• peroxyacids are the diperoxy alkane dioic acids of formula HO 3 C-R-CO 3 H and peroxyalkanoic acids of formula
• R denotes an alkylene group of 2 to 18 carbon atoms especially 2 to 12 carbon atoms, op- tionally incorporating a heteroatom in the carbon chain, such as the nitrogen atom of an amide linkage.
• R denotes an arylene group, e.g. perbenzoic acid, substituted perbenzoic acid and diperoxyisophthalic acid.
• peroxyacids may be carried out by known methods.
• Preferred is the oxidation of the cor- responding organic acid using hydrogen peroxide in an acid medium, notably an organic sulphonic acid such as ethanesulphonic acid or a mineral acid such as sulphuric acid.
• reaction medium comprises a mineral acid, such as sulphuric acid
• all or part of it can be premixed with the hydrogen peroxide to form an equilibrium mixture containing for example permonosulphuric acid that can itself perform the peroxidation reaction.
• premixing separates the exothermic dilution/reaction between hydrogen peroxide and sulphuric acid from the peroxidation reaction.
• DSC differential scanning calorimetry
• Example 1 A phosphate buffer solution was prepared by dissolving 14 grams analytical grade sodium dihydrogen orthophosphate in 1 litre of deionised water. The acidity of the buffer solution was measured and found to be pH 4.5.
• Example 3 Phthalimido-6-peroxyhexanoic acid was prepared by a method similar to Example 1 in WO 90/07501 but with the procedure for working up the reaction modified to embody the present invention, as follows:
• the mixture was cooled to below 5°C in a water/ice bath.
• aqueous hydrogen peroxide approximately 80% w/w was added with continuous stirring into the reaction mixture progressively during a period of about 5 to 10 minutes while keeping the temperature below 5°C, until a total amount of 3.5 moles per mole of carboxylic acid has been introduced, i.e. a 2.5 molar excess compared with the stoichiometric amount.
• the reaction mixture was then stirred for a further 50 minutes.
• reaction mixture was poured into a stirred, ice cold solution consisting of 30 grams disodium hydrogen orthophosphate dissolved in 750 grams demineralised water. Before addition this solution was at approximately pH 8.0 and at the end of the addition the pH had dropped to between pH 4.0 and pH 4.5.
• phthalimido-6-peroxyhexanoic acid was investigated by DSC. The resulting print-out is reproduced as Fig. 5. This sample contained about 5% of the corresponding phthalimido hexanoic acid. It can be seen that this sample showed endothermic melting between about 80 and 90°C followed by exothermic decomposition reaching a maximum at about 125°C.
• Phthalimido-6-peroxyhexanoic acid purified as in Example 3 was mixed, dry, with sodium dihydrogen phosphate in an acid:phosphate weight ratio of 8:2. The resulting mixture was then examined by DSC and the trace is reproduced as Fig. 7. Comparison with Fig. 6 shows that the sharp exothermic decomposition peak shown in Fig. 6 has been transformed into a broader peak extending from ap- proximately 100 to 160°C with a maximum at about 140°C.

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• 1993
  • 1993-03-05 GB GB939304513A patent/GB9304513D0/en active Pending
• 1994
  • 1994-02-17 CA CA002156170A patent/CA2156170A1/en not_active Abandoned
  • 1994-02-17 AU AU61416/94A patent/AU6141694A/en not_active Abandoned
  • 1994-02-17 BR BR9405941A patent/BR9405941A/pt not_active IP Right Cessation
  • 1994-02-17 ES ES94908344T patent/ES2097642T3/es not_active Expired - Lifetime
  • 1994-02-17 EP EP94908344A patent/EP0687293B1/de not_active Revoked
  • 1994-02-17 JP JP6519512A patent/JPH08507761A/ja active Pending
  • 1994-02-17 WO PCT/EP1994/000465 patent/WO1994020600A1/en not_active Application Discontinuation
  • 1994-02-17 DE DE69401499T patent/DE69401499T2/de not_active Revoked
  • 1994-02-24 ZA ZA941270A patent/ZA941270B/xx unknown

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