Method for preparing microemulsions
OwnerHenri L. Rosanoinventor
Life of this patent
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Abstract
A unique method for the preparation of oil-in-water microemulsions is described. In carrying out this method, microemulsions are prepared in a four-step process: (1) a surfactant is selected which is just barely soluble in the oil phase; (2) the surfactant thus selected is dissolved in the oil to be emulsified in an amount effective to yield a fine emulsion of the emulsified oil in an aqueous phase; and (3) the oil, together with its dissolved surfactant, is added to the water phase and shaken or stirred; and (4) finally, there is provided a second surfactant in the water phase which is somewhat more soluble in water than the first surfactant to produce a substantially clear microemulsion of oil in water.
Claims46
A method for dispersing a water-immiscible liquid in an aqueous phase as a microemulsion comprising
- (i) selecting a primary surfactant which is an amphiphatic substance which has a hydrophilic-lipophilic balance not substantially lower than the balance sufficient to render said primary surfactant soluble in said water-immiscible liquid, and which is capable of forming a lactescent emulsion of said water-immiscible liquid dispersed in said aqueous phase;
- (ii) dissolving said primary surfactant in said water-immiscible liquid, the amount of said primary surfactant being sufficient relative to the amount of said water-immiscible liquid that upon dispersion of said water-immiscible liquid in the water phase as a microemulsion, said primary surfactant will be capable of forming a substantially monomolecular layer of surfactant around the individual droplets of said microemulsion;
- (iii) dispersing the solution (ii) of said water-immiscible liquid and primary surfactant into the aqueous phase wherein said liquid is to be dispersed;
- and
- (iv) providing a secondary surfactant in said aqueous phase which has a higher hydrophilic-lipophilic balance than said primary surfactant, the amount of said secondary surfactant being sufficient to disperse said solution (ii) in the water phase as a microemulsion and having a higher hydrophilic-lipophilic balance than said primary surfactant.
A method for dispersing a lipophilic substance in an aqueous phase as a microemulsion comprising
- (i) dissolving said lipophilic substance in a water-immiscible solvent therefore, forming thereby a water-immiscible solution, said solution containing at least 5% of said lipophilic substance;
- (ii) selecting a primary surfactant which is an amphiphatic substance which has a hydrophilic-lipophilic balance not substantially lower than the balance sufficient to render said primary surfactant soluble in said solution and which is capable of forming a lactescent emulsion of said solution (i) in said aqueous phase;
- (iii) dissolving said primary surfactant in said solution, the amount of said primary surfactant being sufficient relative to the amount of said solution that upon dispersion of said solution in the water phase as a microemulsion, said primary surfactant will be capable of forming a substantially monomolecular layer of said surfactant around the individual droplets of said microemulsion;
- (iv) dispersing said solution (iii) of said lipophilic substance, primary surfactant and water-immiscible solvent into the aqueous phase wherein said substance is to be dispersed;
- and
- (v) providing a secondary surfactant in said aqueous phase which has a higher hydrophilic-lipophilic balance than said primary surfactant, the said secondary surfactant being sufficient to disperse said solution (iii) in said water phase as a microemulsion.
A method for dispersing a lipophilic substance in an aqueous phase as a microemulsion comprising
- (i) dissolving said lipophilic substance in a water-immiscible solvent therefor, forming thereby a water-immiscible solution, said solution containing at least 5% of said lipophilic substance, said water-immiscible solvent being substantially more volatile than water;
- (ii) selecting a primary surfactant which is an amphiphatic substance which has a hydrophilic-lipophilic balance not substantially lower than the balance sufficient to render said primary surfactant soluble in said solution and which is capable of forming a lactescent emulsion of said solution (i) in said aqueous phase;
- (iii) dissolving said primary surfactant in said solution, the amount of said primary surfactant being sufficient relative to the amount of said solution that upon dispersion of said solution in the water phase as a microemulsion, said primary surfactant will be capable of forming a substantially monomolecular layer of said surfactant around the individual droplets of said microemulsion;
- (iv) dispersing said solution (iii) of said lipophilic substance, primary surfactant and water-immiscible solvent into the aqueous phase wherein said substance is to be dispersed;
- and
- (v) providing a secondary surfactant in said aqueous phase which has a higher hydrophilic-lipophilic balance than said primary surfactant, the said secondary surfactant being sufficient to disperse said solution (iii) in said water phase as a microemulsion, and, after dispersion of said solution (iii) in the water phase as a microemulsion, said solution is removed by evaporation.
A method for dispersing a water-immiscible liquid having a dominant portion of a light mineral oil in an aqueous phase as a microemulsion comprising
- (i) selecting a primary surfactant which is an amphiphatic substance which has a hydrophilic-lipophilic balance not substantially lower than the balance sufficient to render said primary surfactant soluble in said water-immiscible liquid, and which is capable of forming a lactescent emulsion of said water-immiscible liquid dispersed in said aqueous phase, said primary surfactant being selected from the group consisting of glycerol fatty acid partial esters and ethoxylated nonylphenol having 3-6 ethylene oxide units per mole;
- (ii) dissolving said primary surfactant in said water-immiscible liquid, the amount of said primary surfactant being sufficient relative to the amount of said water-immiscible liquid that upon dispersion of said water-immiscible liquid in the water phase as a microemulsion, said primary surfactant will be capable of forming a substantially monomolecular layer of surfactant around the individual droplets of said microemulsion;
- (iii) dispersing the solution (ii) of said water-immiscible liquid and primary surfactant into the aqueous phase wherein said liquid is to be dispersed;
- and
- (iv) providing a secondary surfactant in said aqueous phase which has a higher hydrophilic-lipophilic balance than said primary surfactant selected from the group consisting of ethoxylated alkyl phenols, ethoxylated fatty alcohols and alkyl amino or amido betaine, the amount of said secondary surfactant being sufficient to disperse said solution (ii) in the water phase as a microemulsion and having a higher hydrophilic-lipophilic balance than said primary surfactant.
A method for dispersing a water-immiscible liquid which consists essentially of benzene in an aqueous phase as a microemulsion comprising
- (i) selecting a primary surfactant which is an amphiphatic substance which has a hydrophilic-lipophilic balance not substantially lower than the balance sufficient to render said primary surfactant soluble in said water-immiscible liquid, and which is capable of forming a lactescent emulsion of said water-immiscible liquid dispersed in said aqueous phase, said primary surfactant consisting essentially of nonylphenol.multidot.1 ethylene oxide;
- (ii) dissolving said primary surfactant in said water-immiscible liquid, the amount of said primary surfactant being sufficient relative to the amount of said water-immiscible liquid that upon dispersion of said water-immiscible liquid in the water phase as a microemulsion, said primary surfactant will be capable of forming a substantially monomolecular layer of surfactant around the individual droplets of said microemulsion;
- (iii) dispersing the solution (ii) of said water-immiscible liquid and primary surfactant into the aqueous phase wherein said liquid is to be dispersed;
- and
- (iv) providing a secondary surfactant in said aqueous phase which has a higher hydrophilic-lipophilic balance than said primary surfactant, said secondary surfactant consisting essentially of nonylphenol.multidot.15 EO, the amount of said secondary surfactant being sufficient to disperse said solution (ii) in the water phase as a microemulsion and having a higher hydrophilic-lipophilic balance than said primary surfactant.
A method for dispersing a water-immiscible liquid which consists essentially of 1-pentanol in an aqueous phase as a microemulsion comprising
- (i) selecting a primary surfactant which is an amphiphatic substance which has a hydrophilic-lipophilic balance not substantially lower than the balance sufficient to render said primary surfactant soluble in said water-immiscible liquid, and which is capable of forming a lactescent emulsion of said water-immiscible liquid dispersed in said aqueous phase, said primary surfactant consisting essentially of ethoxylated nonylphenol having from 5-11 ethylene oxide units;
- (ii) dissolving said primary surfactant in said water-immiscible liquid, the amount of said primary surfactant being sufficient relative to the amount of said water-immiscible liquid that upon dispersion of said water-immiscible liquid in the water phase as a microemulsion, said primary surfactant will be capable of forming a substantially monomolecular layer of surfactant around the individual droplets of said microemulsion;
- (iii) dispersing the solution (ii) of said water-immiscible liquid and primary surfactant into the aqueous phase wherein said liquid is to be dispersed;
- and
- (iv) providing a secondary surfactant in said aqueous phase which has a higher hydrophilic-lipophilic balance than said primary surfactant, said secondary surfactant being selected from the group consisting of ethoxylated phenol having 9.5-15 ethylene oxide units and lauryl alcohol.multidot.7 EO, the amount of said secondary surfactant being sufficient to disperse said solution (ii) in the water phase as a microemulsion and having a higher hydrophilic-lipophilic balance than said primary surfactant.
A method for dispersing a water-immiscible liquid having a dominant portion of a halogenated solvent in an aqueous phase as a microemulsion comprising
- (i) selecting a primary surfactant which is an amphiphatic substance which has a hydrophilic-lipophilic balance not substantially lower than the balance sufficient to render said primary surfactant soluble in said water-immiscible liquid, and which is capable of forming a lactescent emulsion of said water-immiscible liquid dispersed in said aqueous phase, said primary surfactant being selected from the group consisting of ethoxylated sorbitan monoesters of C.sub.12 -C.sub.18 fatty acids, ethoxylated nonylphenol having 7-9 ethylene oxide units per mole;
- (ii) dissolving said primary surfactant in said water-immiscible liquid, the amount of said primary surfactant being sufficient relative to the amount of said water-immiscible liquid that upon dispersion of said water-immiscible liquid in the water phase as a microemulsion, said primary surfactant will be capable of forming a substantially monomolecular layer of surfactant around the individual droplets of said microemulsion;
- (iii) dispersing the solution (ii) of said water-immiscible liquid and primary surfactant into the aqueous phase wherein said liquid is to be dispersed;
- and
- (iv) providing a secondary surfactant in said aqueous phase which has a higher hydrophilic-lipophilic balance than said primary surfactant, said secondary surfactant being selected from the group consisting of ethoxylated sorbitan monoesters of C.sub.12 -C.sub.18 fatty acids, ethoxylated sorbitol monoesters of C.sub.12 -C.sub.18 fatty acids, ethoxylated nonylphenol having 8-15 ethylene oxide units per mole, and lauryl alcohol.multidot.6 EO, the amount of said secondary surfactant being sufficient to disperse said solution (ii) in the water phase as a microemulsion and having a higher hydrophilic-lipophilic balance than said primary surfactant.
A method for dispersing a water-immiscible liquid in an aqueous phase, said aqueous phase having at least 3% of an alkali metal hypochlorite or an alkali-metal peroxide dissolved therein as a microemulsion comprising
- (i) selecting a primary surfactant which is an amphiphatic substance which has a hydrophilic-lipophilic balance not substantially lower than the balance sufficient to render said primary surfactant soluble in said water-immiscible liquid, and which is capable of forming a lactescent emulsion of said water-immiscible liquid dispersed in said aqueous phase, said primary surfactant being selected from the group consisting of nonylphenol.multidot.10-11 EO and ethylene oxide-propylene oxide block polymers having molecular weight of 6,000-7,000 and containing 60-80% ethylene oxide;
- (ii) dissolving said primary surfactant in said water-immiscible liquid, the amount of said primary surfactant being sufficient relative to the amount of said water-immiscible liquid that upon dispersion of said water-immiscible liquid in the water phase as a microemulsion, said primary surfactant will be capable of forming a substantially monomolecular layer of surfactant around the individual droplets of said microemulsion;
- (iii) dispersing the solution (ii) of said water-immiscible liquid and primary surfactant into the aqueous phase wherein said liquid is to be dispersed;
- and
- (iv) providing a secondary surfactant in said aqueous phase which has a higher hydrophilic-lipophilic balance than said primary surfactant, said secondary surfactant being selected from the group consisting of a fatty acid amino betaine and ethoxylated lauryl alcohol, the amount of said secondary surfactant being sufficient to disperse said solution (ii) in the water phase as a microemulsion and having a higher hydrophilic-lipophilic balance than said primary surfactant.
A microemulsion of a water-immiscible liquid dispersed in an aqueous phase having a mixed surfactant system consisting essentially of a primary surfactant and a secondary surfactant, wherein
- (i) said water-immiscible liquid contains a dominant portion of light mineral oil;
- (ii) said primary surfactant is selected from the group consisting of glycerol fatty acid partial esters and ethoxylated nonylphenol having 3 to 6 ethylene oxide units per mol;
- and
- (iii) said secondary surfactant is selected from the group consisting of ethoxylated alkylphenols, ethoxylated fatty alcohols and alkylamino or amido betaine.
A microemulsion of benzene dispersed in an aqueous phase having a mixed surfactant system consisting essentially of a primary surfactant and a secondary surfactant, wherein said primary surfactant consists essentially of nonylphenol.multidot.1EO, and said secondary surfactant consists essentially of nonylphenol.multidot.15EO.
A microemulsion of pentanol dispersed in an aqueous phase having a mixed surfactant system consisting essentially of a primary surfactant and a secondary surfactant, wherein said primary surfactant consists essentially of ethoxylated nonylphenol having from 5 to 11 ethylene oxide units and said secondary surfactant is selected from the group consisting of ethoxylated nonylphenol having 9.5 to 15 ethylene oxide units and lauryl alcohol.multidot.7EO.
A microemulsion of a water-immiscible liquid dispersed in water having a mixed surfactant system consisting essentially of a primary surfactant and a secondary surfactant, wherein
- (i) said water-immiscible liquid has a dominant portion of a halogenated solvent;
- (ii) said primary surfactant is selected from the group consisting of ethoxylated sorbitan monoesters of fatty acids having 12 to 18 carbon atoms, ethoxylated sorbitol monoesters of fatty acids having 12 to 18 carbon atoms, and ethoxylated nonylphenol having 7-9 ethylene oxide units per mol;
- and
- (iii) said secondary surfactant is selected from the group consisting of ethoxylated sorbitan monoesters of fatty acids having 12 to 18 carbon atoms, ethoxylated sorbitol monoesters of fatty acids having 12 to 18 carbon atoms, nonylphenol having 8-15 ethylene oxide units per mol, and lauryl alcohol.multidot.6-10 EO, said secondary surfactant having a higher hydrophilic-lipophilic balance than said primary surfactant.
A microemulsion comprising a dispersion of a water-immiscible liquid in water having a mixed surfactant system consisting essentially of a primary surfactant and a secondary surfactant, wherein said water-immiscible liquid is a solution of an edible fat, wax or oil in n-hexane, said primary surfactant consisting essentially of sorbitan monolaurate, and said secondary surfactant consisting essentially of sorbitan monolaurate.multidot.20EO.
A microemulsion of a water-immiscible solvent having a dominant portion of carbon tetrachloride in an aqueous phase which has at least 3% of an alkali metal hypochlorite or an alkali metal peroxide dissolved therein, said dispersion having a mixed surfactant system consisting essentially of a primary surfactant and a secondary surfactant,
- wherein said primary surfactant is selected from the group consisting of nonylphenol.multidot.10-11EO and ethylene oxidepropylene oxide block polymers having a molecular weight of 6,000-7,000 and containing 60-80% ethylene oxide;
- and
- wherein said secondary surfactant is selected from the group consisting of a fatty amino betaine and ethoxylated lauryl alcohol.
A method for dispersing a water-immiscible liquid in an aqueous phase having at least 3% of an alkali metal hypochlorite, hydrogen peroxide or an alkali metal peroxide dissolved therein as a microemulsion comprising
- (i) selecting a primary surfactant which is an amphiphatic substance which has a hydrophilic-lipophilic balance not substantially lower than the balance sufficient to render said primary surfactant soluble in said water-immiscible liquid, and which is capable of forming a lactescent emulsion of said water-immiscible liquid dispersed in said aqueous phase, said primary surfactant being selected from the group consisting of C.sub.10 -C.sub.22 fatty amine oxides, and a C.sub.10 -C.sub.22 fatty acid soap;
- (ii) dissolving said primary surfactant in said water-immiscible liquid, the amount of said primary surfactant being sufficient relative to the amount of said water-immiscible liquid that upon dispersion of said water-immiscible liquid in the water phase as a microemulsion, said primary surfactant will be capable of forming a substantially monomolecular layer of surfactant around the individual droplets of said microemulsion;
- (iii) dispersing the solution (ii) of said water-immiscible liquid and primary surfactant into the aqueous phase wherein said liquid is to be dispersed;
- and
- (iv) providing a secondary surfactant in said aqueous phase which has a higher hydrophilic-lipophilic balance than said primary surfactant, said secondary surfactant being a C.sub.4 -C.sub.10 tertiary alcohol, the amount of said secondary surfactant being sufficient to disperse said solution (ii) in the water phase as a microemulsion and having a higher hydrophilic-lipophilic balance than said primary surfactant.
Dependencies are inferred from the claim text.