CA2030985A1 - Process for the preparation of 2,2'-oxydisuccinate - Google Patents
Process for the preparation of 2,2'-oxydisuccinateInfo
- Publication number
- CA2030985A1 CA2030985A1 CA 2030985 CA2030985A CA2030985A1 CA 2030985 A1 CA2030985 A1 CA 2030985A1 CA 2030985 CA2030985 CA 2030985 CA 2030985 A CA2030985 A CA 2030985A CA 2030985 A1 CA2030985 A1 CA 2030985A1
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Abstract
ABSTRACT
A process for the preparation of 2,2'-oxydisuccinate is disclosed which utilises a combination of a low reaction temperature and a minimum excess of calcium hydroxide to an organic reactant. The use of a non reactive alkali metal salt of a strong or weak acid in the reaction mixture allows somewhat higher ratios of calcium hydroxide to reactant and somewhat higher temperatures.
2,2'-oxydisuccinate is produced in about 5 hours while gelation of the reaction mixture is substantially minimized.
A process for the preparation of 2,2'-oxydisuccinate is disclosed which utilises a combination of a low reaction temperature and a minimum excess of calcium hydroxide to an organic reactant. The use of a non reactive alkali metal salt of a strong or weak acid in the reaction mixture allows somewhat higher ratios of calcium hydroxide to reactant and somewhat higher temperatures.
2,2'-oxydisuccinate is produced in about 5 hours while gelation of the reaction mixture is substantially minimized.
Description
2 ~
- 1 - C60~8 PROCESSES FOR THE PREPARA~ION OF 2L?'-OXYDISUCCINATE
BACKGROUND OF THE INVENTION
Field o~ the Inventi_ The invention relates to the preparation of a salt of 2,2'-oxydisuccinic acid by a process which produces the salt in about 5 hours at temperatures not greater than 950C while substantially minimizing gelation of the reaction mixture. 2,2'-oxydisuccinic acid and salts thereof are e~ective sequestering agents and are useful as builders in detergent compositions for household, institutional and industrial use.
Related Art 2,2'-oxydisuccinic acid (ODS) and salts thereof are known and are known to have utility as sequest.ering agents and detergent builders. A disadvantage of ODS and salts thexeof as detergsnt builders is that they are relatively expensive to prepare.
~3~8~
- 2 - - C609~
US 3 128 287 (Berg) discloses a preparation of ODS salt by admixing maleic acid with an excess of hydroxide of calcium, barium, magnesium or strontium in the presence of water, then heating the reaction mixture from about one day to about one month at temperatures ranging from 50~C
to reflux temperatures. The process yields a mixture o~
maleic acid and ODS. Example I teaches the preparation of ODS, wherein the aqueous mixture of maleic anhydride and calcium hydroxide is reacted at reflux ~100C) for 4 days.
Subsequently, ODS salt is isolated from the product containing ODS and maleic acids salts.
US 3 635 830 (Lamberti et al) discloses the process for the preparation of ODS based on the process of Berg. The patent teaches separation/purification of two diastereoisomeric forms of ODS obtained by the Berg process. The patent also discloses detergent compositions comprising ODS or salts thereof as detergent builders.
US 4 798 907 (MacBriar ~t al) discloses an improvement in the ODS-forming proc~sses of Berg and Lamberti et al, wherein an alkali metal hydroxide, e.g. sodium hydroxide, is incorporated into a starting reaction mixture. To procIuce yields of about 80% ODS, the process generally involves reacting the mixed starting materials in water for at least 12 hours at temperatures of about 20--100C.
EP 2~6 007A (Procter & Gamble/Bush) teaches a process for the preparation of ODS similar to the process of the MacBriar patent. Mixtures of inorganic base witb water-soluble, inorganic salts of sodium, calcium or mixtures thereof may be used. A particularly preferred reactant combination constitutes maleic acid, malic acid, calcium hydroxide and sodium hydroxide. The ODS yield of about 60% is obtained in about 6 hours.
2~3~
- 1 - C60~8 PROCESSES FOR THE PREPARA~ION OF 2L?'-OXYDISUCCINATE
BACKGROUND OF THE INVENTION
Field o~ the Inventi_ The invention relates to the preparation of a salt of 2,2'-oxydisuccinic acid by a process which produces the salt in about 5 hours at temperatures not greater than 950C while substantially minimizing gelation of the reaction mixture. 2,2'-oxydisuccinic acid and salts thereof are e~ective sequestering agents and are useful as builders in detergent compositions for household, institutional and industrial use.
Related Art 2,2'-oxydisuccinic acid (ODS) and salts thereof are known and are known to have utility as sequest.ering agents and detergent builders. A disadvantage of ODS and salts thexeof as detergsnt builders is that they are relatively expensive to prepare.
~3~8~
- 2 - - C609~
US 3 128 287 (Berg) discloses a preparation of ODS salt by admixing maleic acid with an excess of hydroxide of calcium, barium, magnesium or strontium in the presence of water, then heating the reaction mixture from about one day to about one month at temperatures ranging from 50~C
to reflux temperatures. The process yields a mixture o~
maleic acid and ODS. Example I teaches the preparation of ODS, wherein the aqueous mixture of maleic anhydride and calcium hydroxide is reacted at reflux ~100C) for 4 days.
Subsequently, ODS salt is isolated from the product containing ODS and maleic acids salts.
US 3 635 830 (Lamberti et al) discloses the process for the preparation of ODS based on the process of Berg. The patent teaches separation/purification of two diastereoisomeric forms of ODS obtained by the Berg process. The patent also discloses detergent compositions comprising ODS or salts thereof as detergent builders.
US 4 798 907 (MacBriar ~t al) discloses an improvement in the ODS-forming proc~sses of Berg and Lamberti et al, wherein an alkali metal hydroxide, e.g. sodium hydroxide, is incorporated into a starting reaction mixture. To procIuce yields of about 80% ODS, the process generally involves reacting the mixed starting materials in water for at least 12 hours at temperatures of about 20--100C.
EP 2~6 007A (Procter & Gamble/Bush) teaches a process for the preparation of ODS similar to the process of the MacBriar patent. Mixtures of inorganic base witb water-soluble, inorganic salts of sodium, calcium or mixtures thereof may be used. A particularly preferred reactant combination constitutes maleic acid, malic acid, calcium hydroxide and sodium hydroxide. The ODS yield of about 60% is obtained in about 6 hours.
2~3~
The MacBriar et al and Bush patents rely on incorporation of alkali metal hydroxide into the reactant mixture to minimize gelation of the reactants and to increase yields of ODS. Alkali metal hydroxides indeed produce homogeneous solutions, but unlike the alkaline earth metal hydroxides, generate higher pHs and result in a gradual decomposition o~ ODS to fumarate and malate under the reaction conditions employed by the MacBriar et al. and Bush patents.
A workable and cost-efficient production of ODS salt must be directed towards optimizing the process conditions in such a manner that gelation of the reaction mixture is substantially minimized while overall energy requirements for the reaction are significantly lower~d. There have been different approaches to the problem of producing ODS
at a lower cost. However, none of these approaches has been completely satisfactory.
Accordingly, it is an object of the present invention to provide a process which produces the salt of ODS.
It is a further object of this invention to produce the ODS salt at temperatures lower than 95C, or even lower than 75C, in about 5 hours while substantially minimizing the gelation of a reaction mixture.
These and other objects and advantages will appear as the description proceeds.
2030~3 DEFINITION OF TH[E INVENT ON
This invention provides a ~irst process (Process A) for the preparation of a salt of ODS, the process comprising the steps of:
(i) forming an aqueous mixture comprising:
(a~ a malate moiety, 0 (b) a maleate moiety, and (c) an alkaline earth metal hydroxide, wherein the mole ratio of c:(a + b~ is from 1.01:1.0 to 1.2:1.0; and (ii~ reacting said aqueous mixture by heating at a temperature not greater than 75C for at least 5 hours to ~orm a reaction product in which gelation of said aqueous mixture is substantially minimized and which contains the salt of ODS.
The invention further provides a second process (Process B) for the preparation of a salt of ODS, the process comprising the steps of:
(i) forming an aqueous mixture comprising:
(a) a malate moiety, ~b) a maleate moiety, (c) an alkaline earth metal hydroxide, and ~ - C609~
(d) a non reactive alkali metal salt o~ a strong or weak acid, wherein the mole ratio of c:~a+h) is from 1.01:1.0 to 2.0:1.0; and (ii) reacting said aqueous mixture by heating at a temperature not greater than 95C for at least 5 hours to form a reaction product in which gelation of said aqueous mixture is substantially minimized and which contains said compound of 2,2'-oxydisuccinic acid.
DETAILED DESCRIPTION OF THE INVE~
I~ its broadest aspe~t, the invention provides two alternative processes for synthesising the salt o~ ODS in about 5 hours at temperatures not greater than 95C while substantially minimizing gelation of the reaction mixture.
An alkaline earth metal salt of ODS may be isolated from other organic species contained in the reaction product obtained by either of the inventive processes and converted to ODS (Formula I) or ODS salts such as monovalent cation salts, ammonium salts, morpholinium salts, alkanolammonium salts and mixtures thereof, by methods known in the art. Such methods are disclosed, for example, in US 3 128 287 (Berg) and US 3 635 830 (Lamhertl et al) discussed above and incorporated herein by ~/
reference. As noted, US 3 635 830 also discloses detergent compositions containiny ODS or salts thereo~.
2 ~ 5 ~ORMULA (I~
H H
HOOC - C -H H -C COOH
1. 1 HOOC -- C -H H - C - COOH
In Pxocess A, the molar ratio of the alkaline earth metal hydroxide to organic reactants (molar sum of malate and maleate) of 1.01:1.0 to 1.2:1.0 and the reaction temperature of not greater than 750c are critical for obtaining the ODS salt product in about 5 hours and minimizing gelation of the reaction mixture process.
However, whenever one or both of these critical parameters exceed the critical values recited above, the alternative process (Process B) provided by this invention can still accomplish the ODS salt preparation in about 5 hours and substantially minimize gelation of the reaction by virtue of the inclusion into the reaction mixture of a non reactive alkali metal salt of a weak or strong acid, for example, sodium acetate. By non reactive alkali metal salt of a weak or strong acid is meant an alkali metal salt that does not participate in the reaction while still inhibiting gelation through electrolyte effects. In the alternate process the incorporation o~ this non reactive alkali metal salt into the reaction mixture is critical and permits the molar ratio of the alkaline earth metal hydroxide to the organic reactants to vary ~rom 1.01:1 to 2~3~3 - 7 - C6~9~
2.0:1.0 and the reaction temperatures to increase up to By virtue of incorporation of the non reactive alkali metal salt of a strong or weak acid into the starting reaction mixture of Process B a larger range of the molar ratio of alkaline earth metal hydroxide to malate and maleate and hiyher react,ion temperatures may be used in Process B ~han in Process A.
The A and B processes ot' this invention for the preparation of the salt of ODS include formin~ an aqueous mixture of starting reactants containing a malate moiety, a maleate moiety and an alkaline earth metal hydroxide.
In the a~ueous media of the processes herein the malate and maleate would be expected to take anionic forms represented by Formulas II and III respectively. The chemically suitable forms of malate and maleate reactants include acids and the anhydride of malei~ acid. The molar ratio of II (malate) to III (maleate) is preferably 1:5 to 1:1. More preferably, to limit the excess maleate the molar ratio is 1:3 to 1:1.
2~3~
- ~ - C609 PORMnLA (II) FORMDL~ (III3 (Malate) (Maleate) OH H H H
~- C C H C - C
O='~C C=O O--c c=o O O O o ~) 9 ~ (3 The alkaline earth metal hydroxide in the reaction mixtures o~ the inventive processes A and B is selected from the group consisting of barium hydroxide, strontium hydroxide or calcium hydroxide. The most preferred alkaline earth metal hydroxide for use in this invention is calcium hydroxide.
The ODS salt forming reactions A and B of the present invention are conducted at high concentration in aqueous media to afford efficacy and high throughput. The amount of water present may vary and is preferably su~ficient to permit the reaction to proceed with a solute concentration of 30% to 75~. The amount may however be more or less depending on design parameters.
The non reactive alkali mekal salt of Process B is preferably selected from the group consisting oE alkali metal chlorides, acetates, xylene sulfonates and the like, for example, sodium chloride, sodium or potassium acetate, sodium xylene sulfonate and mixtures thereof. Preferably, from 1 to 10 weight % o~ the alkali me~al salt is used.
When either process A or process B is employed the present xeaction mixtures are characteristically non-viscous, coarse, powdexy suspensions with temperature-corrected pH
readings of 11.5 to 12. The gelation of the reaction mixture upon subsequent heating is substantially minimized. The appearance of the reaction mixtures does not vary significantly over the time of the reaction and the reackion mixtures may be stirred without diXficulty.
Desirably, the reactants of the starting mixture for the ODS salt forming process A or B are combined in water using physical agitation. In the preferred embodiments of tha invention, the alkaline earth metal hydroxide is added to an aqueous mixture of the malate and maleate moieties or the alkaline earth metal hydroxide is added to an aqueous solution solution of the malate moiety and is followed by addition of the maleate moiety. If the hydroxide is first added to the maleate in the absence of malate, poor yields of ODS will usually be obtained. The reaction is carried out in an apparatus equipped with stirring means, e.g., on a laboratory scale, a mechanical stirring device or a magnetic stirring bar is employedO
The apparatus may also be equipped with a condensor for safety reasons and to provide some means of ~ondensing watex which evaporates, so that it returns to the reaction mixture.
The reaction may be conducted at atmospheric pressure.
The reaction temperature for both processes is suitably at least 40C, for example, from 50 to 95C, preferably from 65 to 85C. Whenever the practitioner opts for a reaction temperature greater than 75C, the addition of the non reactive alkali metal salt as recited above in Process B
- 10 - ~6~98 is critical to prevent the gelation of the reactant mixture.
To minimize gelation, the reaction temperature is maintained for at least 5 hours and preferably no longer than 24 hours. When the ODS salt Porming reaction A or B
has been con~ucted to the desired extent and after at least 5 hours the reaction may be arrested by cooling to less than 40C, more preferably to ambient temperature.
The aqueous reaction product typically contains a mixture of 2,2'-oxydisuccinate plus malate plus maleate plus fumarate.
In de~ining the ODS salt forming processes of this invention it is intended to include both batch and continuous processes.
The reaction products obtained by the processes of this invention contain the alkaline earth metal salt of ODS and may be worked up by methods known in the art. Generally, the work up comprises the steps of reduction of calcium content in the product mixture and acidification or conversion into monovalent cation salts, ammonium salts, morpholinium salts, alkanolammonium salts and mixtures thereof.
The calcium content o~ the reaction products may be reduced by conventional means. Removal of calcium can be carried out in a number o~ ways known in the art. In general, simply adding a calcium precipitating material will su~fice. Such calcium precipitating materials include alkali metal carbonate, pyrophosphate, sulfates, bicarbonate and/or alkali metal silicate and mixtures thereo~, for example, the addition of sodium carbonate 3S will convert the ~lkaline earth metal salt obtained to the ~3~
~ C609$
sodium salt~ The resulting calcium precipitate can thereafter be removed from the aqueous reackion product mixture by filtration. In an alternative mode, removing calcium from the aqueous reaction product mixtures involves treatment of said mixtures with an appropriate insoluble ion exchange resin or ~eolite. No matter what technique is employed, the calcium content of the ODS salt prepared by methods herein should desirably be reduced to the extent that calcium i5 present in an amount of no more than 1.0~ of the ODS salt and preferably less than 0.2%, in order to form compositions particularly suitable as detergent builders. This can be accomplished by the method o~ Defensive Publication US 101 805T.
ODS salks formed herein can also be treated, after calcium removal, in a further step, using organic or aqueous solvent extraction to remove excess reactants, such as maleates, or organic reaction by-products, such as fumarates. This can, for example, be accomplished by conventional salt separation procedures using a solvent such as a mixture o~ methanol and water (4:1 v/v) in which these excess reactants and reaction by-products are relatively soluble and in which the desired ODS salt is relatively insoluble.
At any stage after the ODS salt formation, the reaction product can be concentrated by removal of water to the desired extent. Water removal can, for example, involve substantially complete drying of the reaction product mixture, e.g., by spray drying, so that the ODS salt is recovered in solid, e.g., granular, form. The sodium salt o~ OD5 in the form of aqueous liquid may be utilized directly in the preparation of detergent compositions or laundry additive products o~ the types more ~ully described hereinafter.
~3~
- 12 - C6~98 After reduction of the calcium content in the reaction product mixtures, it is possible, iP desired, to acidify the product mixtures using conventional acidification or ion exchange techniques to convert the ODS salts therein to their free acid form. Normally, however, the ODS
materials o~ this invention can, after calcium depletion or complete replacement by sodium, be used as builders in their water-soluble salt form, and such acidification is therefore not usually necessary or desirable.
When converted into suitable form, the ODS salts can be used as sequestering builders in a wide variety of detergent or laundry additive compositions.
Detergent compositions incorporating the ODS salt prepared using the processes of this invention contain as essential components from 0.5% to 98% of a surfactant and from 2~ to 99.5% of the ODS compounds as a detergency builder, generally in sodium-salt form.
Surfactants that are useful in the present invention are the anionic (soap and nonsoap), nonionic, zwitterionic and ampholytic compounds. The chemical nature of these detergent compounds is not an essential feature of the present invention. Moreover, such detergent compounds are well known to those skilled in the detergent art and the patent and pr:inted litera~ure are replete with disclosures of such compounds. Typical of such literature are "Surface Active Agents" by Schwartz and Perry and "Surface Active Agents and Detergents" by Schwartz, Perry and Berch, the disclosures of which are incorporated by reference herein.
The ODS builder can be used either as the sole builder or where desired can be used in conjunction with other ~3~
- 13 - ~6098 well-known builders, examples of which include water-solu~le salts of phosphates, pyrophosphates, orthophosphates, polyphosphates, phosphonates, carbonates, polyhydroxysulfonates, polyacetates, carboxylates, polycarboxylates, succinates and the like.
In addition to the sur~actant and builder there may be optionally present additional ingredients which enhance the per~ormance o~ the detergent composition. Typical examples thereo~ include the well known soil suspending agents, hydrotropes, corrosion inhibitors, dyes, perfumes, fillers, optical brighteners, enzymes, suds boosters, suds depressants, germicides, anti-tarnishing agents, cationic detergents, softeners, bleaches, bu~fers and the like.
The detergent compositions of the present invention may be in any of the usual physical forms for such compositions, such as powders, beads, flakes, bars, tablets, noodles, liquids, pastes and the like. The detergent compositions are prepared and utilized in the conventional manner. The wash solutions thereof desirably have a pH from 7 to 12, pre~erably from 9 to 11. At pH values below 8.6 some of the salts of the oxydisuccinic acid will be present in the acid salt form and some in the normal salt form.
In addition to their utility as builders in detergent and laundry additive compositions, the ODS salts o~ the inv~ntion can, a~ter reducing their calcium content, also be utilized in other contexts wherein water hardness sequestration is required. Other uses are provided in water so~tening compositions, devices and methods and boiler descaling compositions and methods.
. ~3~3~
- 14 - c~098 It should also be noted that when ODS is employed as the free acid or as partly neutralized salt it has utility in metal cleaning compositions under pH conditions of 2 to 5.
EXAMPLES
The following examples are designed to illustrate, but not to limit, the practice o~ the instant invention. All percentages and parts herein are by weight unless indicated otherwise. All ratios herein are mole ratios unless indicated otherwise.
Reaction mixture samples and reaction products were analysed by HPLC. The HPLC analysis was carried out using a Hitachi instrument. The mobile phase was a PIC D/4 using phosphoric acid at a pH of 2. The column was an "octyl reversible" Regis 15 cm x 4.6 mm internal diameter.
The flow rate was 1.5 ml/mm at a wavelength of 205 nm.
Examples 1-5 illustrate the critical effect of reaction temperature on increasing the yield of ODS while substantially minimizing gelation of the reaction mixture.
13.4 grams (0.1 mole) malic acid and 65 ml of water were placed into a 100 ml three neck flask. 16.5 grams ~0.22 moles) of calcium hydroxide were added to the flask with stirring at 50-60C. After 2-3 minutes, 9.8 grams (0.1 mole) Oæ maleic anhydride were added to the flask. The mixtures of Examples 1-5 were heated for 6 hours at varying temperatures with samples being removed periodically for NMR analysis. The reaction was terminated after slx hours. The reaction mixture was ~ 15 - C6~8 worked up by distilling off the water using a ~lash evaporatox. The reaction products of the acids were analysed by HPLC. Examples 1-5 at various temperatures are summarised in Table I. The percentages reported are "as is" percentages and are not normalised to 100~.
Normalisation would make these values higher.
TABLE I
Reaction Reaction Product composition Example Temp. (C) % ODS % Malic % fumaric % maleic 1 60 41.0 30.6 0.36 9.7 2 7V 44.4 26.7 2.1 5.5 3 80 36.2 31.3 5.2 4.4 4 go 37.4 27.8 6.1 1.8 100 31.1 39.7 0.4 6.4 ~he ODS yield was decreased in Examples 3-5 when reaction temperatures of 80c, 90C and 100C were employed compared to Examples 1 and 2 wherein reaction temperatures of 60C and 70C were employed. Gelation was observed at the higher temperatures of Examples 3, ~ and 5.
Example 6 illustrates the criticality of maintaining a reaction temperature of not greater than 75~C to minimize gelation of the reaction mixture. While the conversion to ODS is good, the lumpiness of the reaction mixture due to yelation is extremely undesirable.
13.4 grams (0.1 mole) of malic acid, 75 ml of water and 1 grams (0.24 mole) of calcium hydroxide were placed into a ~3~
~ C6098 100 ml, three neck flask. The mixture was stirred for 2-3 minutes and 9.8 grams (0.1 mole) of maleic anhydrida were added to th~ flask. The reaction mixture was stirred for 7-8 hours at 75-80C. The mixture was marginally stirrable and substantial gelation was observed. The reaction product was analysed by HPLC to contain:
43.5% ODS, 17.0% malic, 3.1% fumaric, and 3.6% maleic.
EXA~ a_~=2 Examples 7-9 incorporate a non reactive sodium salt of the strong or weak acid listed in Table II into the starting reaction mixture as described in the Process B of this specification.
13.4 grams (0.1) mole of malic acid, 60 ml of water and 20 grams (0.27 mole) of calcium hydroxide were placed into a 100 ml, three neck flasX. The mixture was stirred well for 2-3 minutes and a sodium salt of the strong or weak acid listed in Table II was added followed by addition of 9.8 grams (0.1 mole) of maleic anhydride. The mixture was stirred at 75-80C for 7-8 hours. No gelation of the reaction mixture was observed. The reaction products of the acids were analysed by HPLC as in Table I the percentages are "as is". Examples 7-9 are summarised in Tables II and III.
2 ~
TABLE II
Example Non Reactive Molar Ratio Appearance of Sodium Salt of Calcium Reaction Mixture Present in Hydroxide to Starting Malate and Mixture Maleate _~___________________________________________________~____ 7 0.6 g sodium 1.35 No gelation -chloride Some stirrable solid 8 5.3 g sodium 1.35 No gelation xylene sulfonate 9 4.0 g sodium 1.35 No gelation acetate TABLE III
Reaction Product Composition Example % ODS % Malic ~ fumaric % maleic _ _ ___________________ __ 7 33.2 19.3 1.7 5.7 8 32.5 20.0 3.3 1.5 9 Z6.2 21.0 4.3 12.3 Examples 7-9 illustrate that incorporation o~ a non reactive sodium salt of a strong or wea~ acid into the starting mixture prevents gelation of the reaction mixture when the ODS salt forming reaction is conducted at temperatures greater than 75C or when the molar 2 ~
ratio of calcium hydroxide to malate and maleat~
greater than 1. ol to 1. 2 .
A workable and cost-efficient production of ODS salt must be directed towards optimizing the process conditions in such a manner that gelation of the reaction mixture is substantially minimized while overall energy requirements for the reaction are significantly lower~d. There have been different approaches to the problem of producing ODS
at a lower cost. However, none of these approaches has been completely satisfactory.
Accordingly, it is an object of the present invention to provide a process which produces the salt of ODS.
It is a further object of this invention to produce the ODS salt at temperatures lower than 95C, or even lower than 75C, in about 5 hours while substantially minimizing the gelation of a reaction mixture.
These and other objects and advantages will appear as the description proceeds.
2030~3 DEFINITION OF TH[E INVENT ON
This invention provides a ~irst process (Process A) for the preparation of a salt of ODS, the process comprising the steps of:
(i) forming an aqueous mixture comprising:
(a~ a malate moiety, 0 (b) a maleate moiety, and (c) an alkaline earth metal hydroxide, wherein the mole ratio of c:(a + b~ is from 1.01:1.0 to 1.2:1.0; and (ii~ reacting said aqueous mixture by heating at a temperature not greater than 75C for at least 5 hours to ~orm a reaction product in which gelation of said aqueous mixture is substantially minimized and which contains the salt of ODS.
The invention further provides a second process (Process B) for the preparation of a salt of ODS, the process comprising the steps of:
(i) forming an aqueous mixture comprising:
(a) a malate moiety, ~b) a maleate moiety, (c) an alkaline earth metal hydroxide, and ~ - C609~
(d) a non reactive alkali metal salt o~ a strong or weak acid, wherein the mole ratio of c:~a+h) is from 1.01:1.0 to 2.0:1.0; and (ii) reacting said aqueous mixture by heating at a temperature not greater than 95C for at least 5 hours to form a reaction product in which gelation of said aqueous mixture is substantially minimized and which contains said compound of 2,2'-oxydisuccinic acid.
DETAILED DESCRIPTION OF THE INVE~
I~ its broadest aspe~t, the invention provides two alternative processes for synthesising the salt o~ ODS in about 5 hours at temperatures not greater than 95C while substantially minimizing gelation of the reaction mixture.
An alkaline earth metal salt of ODS may be isolated from other organic species contained in the reaction product obtained by either of the inventive processes and converted to ODS (Formula I) or ODS salts such as monovalent cation salts, ammonium salts, morpholinium salts, alkanolammonium salts and mixtures thereof, by methods known in the art. Such methods are disclosed, for example, in US 3 128 287 (Berg) and US 3 635 830 (Lamhertl et al) discussed above and incorporated herein by ~/
reference. As noted, US 3 635 830 also discloses detergent compositions containiny ODS or salts thereo~.
2 ~ 5 ~ORMULA (I~
H H
HOOC - C -H H -C COOH
1. 1 HOOC -- C -H H - C - COOH
In Pxocess A, the molar ratio of the alkaline earth metal hydroxide to organic reactants (molar sum of malate and maleate) of 1.01:1.0 to 1.2:1.0 and the reaction temperature of not greater than 750c are critical for obtaining the ODS salt product in about 5 hours and minimizing gelation of the reaction mixture process.
However, whenever one or both of these critical parameters exceed the critical values recited above, the alternative process (Process B) provided by this invention can still accomplish the ODS salt preparation in about 5 hours and substantially minimize gelation of the reaction by virtue of the inclusion into the reaction mixture of a non reactive alkali metal salt of a weak or strong acid, for example, sodium acetate. By non reactive alkali metal salt of a weak or strong acid is meant an alkali metal salt that does not participate in the reaction while still inhibiting gelation through electrolyte effects. In the alternate process the incorporation o~ this non reactive alkali metal salt into the reaction mixture is critical and permits the molar ratio of the alkaline earth metal hydroxide to the organic reactants to vary ~rom 1.01:1 to 2~3~3 - 7 - C6~9~
2.0:1.0 and the reaction temperatures to increase up to By virtue of incorporation of the non reactive alkali metal salt of a strong or weak acid into the starting reaction mixture of Process B a larger range of the molar ratio of alkaline earth metal hydroxide to malate and maleate and hiyher react,ion temperatures may be used in Process B ~han in Process A.
The A and B processes ot' this invention for the preparation of the salt of ODS include formin~ an aqueous mixture of starting reactants containing a malate moiety, a maleate moiety and an alkaline earth metal hydroxide.
In the a~ueous media of the processes herein the malate and maleate would be expected to take anionic forms represented by Formulas II and III respectively. The chemically suitable forms of malate and maleate reactants include acids and the anhydride of malei~ acid. The molar ratio of II (malate) to III (maleate) is preferably 1:5 to 1:1. More preferably, to limit the excess maleate the molar ratio is 1:3 to 1:1.
2~3~
- ~ - C609 PORMnLA (II) FORMDL~ (III3 (Malate) (Maleate) OH H H H
~- C C H C - C
O='~C C=O O--c c=o O O O o ~) 9 ~ (3 The alkaline earth metal hydroxide in the reaction mixtures o~ the inventive processes A and B is selected from the group consisting of barium hydroxide, strontium hydroxide or calcium hydroxide. The most preferred alkaline earth metal hydroxide for use in this invention is calcium hydroxide.
The ODS salt forming reactions A and B of the present invention are conducted at high concentration in aqueous media to afford efficacy and high throughput. The amount of water present may vary and is preferably su~ficient to permit the reaction to proceed with a solute concentration of 30% to 75~. The amount may however be more or less depending on design parameters.
The non reactive alkali mekal salt of Process B is preferably selected from the group consisting oE alkali metal chlorides, acetates, xylene sulfonates and the like, for example, sodium chloride, sodium or potassium acetate, sodium xylene sulfonate and mixtures thereof. Preferably, from 1 to 10 weight % o~ the alkali me~al salt is used.
When either process A or process B is employed the present xeaction mixtures are characteristically non-viscous, coarse, powdexy suspensions with temperature-corrected pH
readings of 11.5 to 12. The gelation of the reaction mixture upon subsequent heating is substantially minimized. The appearance of the reaction mixtures does not vary significantly over the time of the reaction and the reackion mixtures may be stirred without diXficulty.
Desirably, the reactants of the starting mixture for the ODS salt forming process A or B are combined in water using physical agitation. In the preferred embodiments of tha invention, the alkaline earth metal hydroxide is added to an aqueous mixture of the malate and maleate moieties or the alkaline earth metal hydroxide is added to an aqueous solution solution of the malate moiety and is followed by addition of the maleate moiety. If the hydroxide is first added to the maleate in the absence of malate, poor yields of ODS will usually be obtained. The reaction is carried out in an apparatus equipped with stirring means, e.g., on a laboratory scale, a mechanical stirring device or a magnetic stirring bar is employedO
The apparatus may also be equipped with a condensor for safety reasons and to provide some means of ~ondensing watex which evaporates, so that it returns to the reaction mixture.
The reaction may be conducted at atmospheric pressure.
The reaction temperature for both processes is suitably at least 40C, for example, from 50 to 95C, preferably from 65 to 85C. Whenever the practitioner opts for a reaction temperature greater than 75C, the addition of the non reactive alkali metal salt as recited above in Process B
- 10 - ~6~98 is critical to prevent the gelation of the reactant mixture.
To minimize gelation, the reaction temperature is maintained for at least 5 hours and preferably no longer than 24 hours. When the ODS salt Porming reaction A or B
has been con~ucted to the desired extent and after at least 5 hours the reaction may be arrested by cooling to less than 40C, more preferably to ambient temperature.
The aqueous reaction product typically contains a mixture of 2,2'-oxydisuccinate plus malate plus maleate plus fumarate.
In de~ining the ODS salt forming processes of this invention it is intended to include both batch and continuous processes.
The reaction products obtained by the processes of this invention contain the alkaline earth metal salt of ODS and may be worked up by methods known in the art. Generally, the work up comprises the steps of reduction of calcium content in the product mixture and acidification or conversion into monovalent cation salts, ammonium salts, morpholinium salts, alkanolammonium salts and mixtures thereof.
The calcium content o~ the reaction products may be reduced by conventional means. Removal of calcium can be carried out in a number o~ ways known in the art. In general, simply adding a calcium precipitating material will su~fice. Such calcium precipitating materials include alkali metal carbonate, pyrophosphate, sulfates, bicarbonate and/or alkali metal silicate and mixtures thereo~, for example, the addition of sodium carbonate 3S will convert the ~lkaline earth metal salt obtained to the ~3~
~ C609$
sodium salt~ The resulting calcium precipitate can thereafter be removed from the aqueous reackion product mixture by filtration. In an alternative mode, removing calcium from the aqueous reaction product mixtures involves treatment of said mixtures with an appropriate insoluble ion exchange resin or ~eolite. No matter what technique is employed, the calcium content of the ODS salt prepared by methods herein should desirably be reduced to the extent that calcium i5 present in an amount of no more than 1.0~ of the ODS salt and preferably less than 0.2%, in order to form compositions particularly suitable as detergent builders. This can be accomplished by the method o~ Defensive Publication US 101 805T.
ODS salks formed herein can also be treated, after calcium removal, in a further step, using organic or aqueous solvent extraction to remove excess reactants, such as maleates, or organic reaction by-products, such as fumarates. This can, for example, be accomplished by conventional salt separation procedures using a solvent such as a mixture o~ methanol and water (4:1 v/v) in which these excess reactants and reaction by-products are relatively soluble and in which the desired ODS salt is relatively insoluble.
At any stage after the ODS salt formation, the reaction product can be concentrated by removal of water to the desired extent. Water removal can, for example, involve substantially complete drying of the reaction product mixture, e.g., by spray drying, so that the ODS salt is recovered in solid, e.g., granular, form. The sodium salt o~ OD5 in the form of aqueous liquid may be utilized directly in the preparation of detergent compositions or laundry additive products o~ the types more ~ully described hereinafter.
~3~
- 12 - C6~98 After reduction of the calcium content in the reaction product mixtures, it is possible, iP desired, to acidify the product mixtures using conventional acidification or ion exchange techniques to convert the ODS salts therein to their free acid form. Normally, however, the ODS
materials o~ this invention can, after calcium depletion or complete replacement by sodium, be used as builders in their water-soluble salt form, and such acidification is therefore not usually necessary or desirable.
When converted into suitable form, the ODS salts can be used as sequestering builders in a wide variety of detergent or laundry additive compositions.
Detergent compositions incorporating the ODS salt prepared using the processes of this invention contain as essential components from 0.5% to 98% of a surfactant and from 2~ to 99.5% of the ODS compounds as a detergency builder, generally in sodium-salt form.
Surfactants that are useful in the present invention are the anionic (soap and nonsoap), nonionic, zwitterionic and ampholytic compounds. The chemical nature of these detergent compounds is not an essential feature of the present invention. Moreover, such detergent compounds are well known to those skilled in the detergent art and the patent and pr:inted litera~ure are replete with disclosures of such compounds. Typical of such literature are "Surface Active Agents" by Schwartz and Perry and "Surface Active Agents and Detergents" by Schwartz, Perry and Berch, the disclosures of which are incorporated by reference herein.
The ODS builder can be used either as the sole builder or where desired can be used in conjunction with other ~3~
- 13 - ~6098 well-known builders, examples of which include water-solu~le salts of phosphates, pyrophosphates, orthophosphates, polyphosphates, phosphonates, carbonates, polyhydroxysulfonates, polyacetates, carboxylates, polycarboxylates, succinates and the like.
In addition to the sur~actant and builder there may be optionally present additional ingredients which enhance the per~ormance o~ the detergent composition. Typical examples thereo~ include the well known soil suspending agents, hydrotropes, corrosion inhibitors, dyes, perfumes, fillers, optical brighteners, enzymes, suds boosters, suds depressants, germicides, anti-tarnishing agents, cationic detergents, softeners, bleaches, bu~fers and the like.
The detergent compositions of the present invention may be in any of the usual physical forms for such compositions, such as powders, beads, flakes, bars, tablets, noodles, liquids, pastes and the like. The detergent compositions are prepared and utilized in the conventional manner. The wash solutions thereof desirably have a pH from 7 to 12, pre~erably from 9 to 11. At pH values below 8.6 some of the salts of the oxydisuccinic acid will be present in the acid salt form and some in the normal salt form.
In addition to their utility as builders in detergent and laundry additive compositions, the ODS salts o~ the inv~ntion can, a~ter reducing their calcium content, also be utilized in other contexts wherein water hardness sequestration is required. Other uses are provided in water so~tening compositions, devices and methods and boiler descaling compositions and methods.
. ~3~3~
- 14 - c~098 It should also be noted that when ODS is employed as the free acid or as partly neutralized salt it has utility in metal cleaning compositions under pH conditions of 2 to 5.
EXAMPLES
The following examples are designed to illustrate, but not to limit, the practice o~ the instant invention. All percentages and parts herein are by weight unless indicated otherwise. All ratios herein are mole ratios unless indicated otherwise.
Reaction mixture samples and reaction products were analysed by HPLC. The HPLC analysis was carried out using a Hitachi instrument. The mobile phase was a PIC D/4 using phosphoric acid at a pH of 2. The column was an "octyl reversible" Regis 15 cm x 4.6 mm internal diameter.
The flow rate was 1.5 ml/mm at a wavelength of 205 nm.
Examples 1-5 illustrate the critical effect of reaction temperature on increasing the yield of ODS while substantially minimizing gelation of the reaction mixture.
13.4 grams (0.1 mole) malic acid and 65 ml of water were placed into a 100 ml three neck flask. 16.5 grams ~0.22 moles) of calcium hydroxide were added to the flask with stirring at 50-60C. After 2-3 minutes, 9.8 grams (0.1 mole) Oæ maleic anhydride were added to the flask. The mixtures of Examples 1-5 were heated for 6 hours at varying temperatures with samples being removed periodically for NMR analysis. The reaction was terminated after slx hours. The reaction mixture was ~ 15 - C6~8 worked up by distilling off the water using a ~lash evaporatox. The reaction products of the acids were analysed by HPLC. Examples 1-5 at various temperatures are summarised in Table I. The percentages reported are "as is" percentages and are not normalised to 100~.
Normalisation would make these values higher.
TABLE I
Reaction Reaction Product composition Example Temp. (C) % ODS % Malic % fumaric % maleic 1 60 41.0 30.6 0.36 9.7 2 7V 44.4 26.7 2.1 5.5 3 80 36.2 31.3 5.2 4.4 4 go 37.4 27.8 6.1 1.8 100 31.1 39.7 0.4 6.4 ~he ODS yield was decreased in Examples 3-5 when reaction temperatures of 80c, 90C and 100C were employed compared to Examples 1 and 2 wherein reaction temperatures of 60C and 70C were employed. Gelation was observed at the higher temperatures of Examples 3, ~ and 5.
Example 6 illustrates the criticality of maintaining a reaction temperature of not greater than 75~C to minimize gelation of the reaction mixture. While the conversion to ODS is good, the lumpiness of the reaction mixture due to yelation is extremely undesirable.
13.4 grams (0.1 mole) of malic acid, 75 ml of water and 1 grams (0.24 mole) of calcium hydroxide were placed into a ~3~
~ C6098 100 ml, three neck flask. The mixture was stirred for 2-3 minutes and 9.8 grams (0.1 mole) of maleic anhydrida were added to th~ flask. The reaction mixture was stirred for 7-8 hours at 75-80C. The mixture was marginally stirrable and substantial gelation was observed. The reaction product was analysed by HPLC to contain:
43.5% ODS, 17.0% malic, 3.1% fumaric, and 3.6% maleic.
EXA~ a_~=2 Examples 7-9 incorporate a non reactive sodium salt of the strong or weak acid listed in Table II into the starting reaction mixture as described in the Process B of this specification.
13.4 grams (0.1) mole of malic acid, 60 ml of water and 20 grams (0.27 mole) of calcium hydroxide were placed into a 100 ml, three neck flasX. The mixture was stirred well for 2-3 minutes and a sodium salt of the strong or weak acid listed in Table II was added followed by addition of 9.8 grams (0.1 mole) of maleic anhydride. The mixture was stirred at 75-80C for 7-8 hours. No gelation of the reaction mixture was observed. The reaction products of the acids were analysed by HPLC as in Table I the percentages are "as is". Examples 7-9 are summarised in Tables II and III.
2 ~
TABLE II
Example Non Reactive Molar Ratio Appearance of Sodium Salt of Calcium Reaction Mixture Present in Hydroxide to Starting Malate and Mixture Maleate _~___________________________________________________~____ 7 0.6 g sodium 1.35 No gelation -chloride Some stirrable solid 8 5.3 g sodium 1.35 No gelation xylene sulfonate 9 4.0 g sodium 1.35 No gelation acetate TABLE III
Reaction Product Composition Example % ODS % Malic ~ fumaric % maleic _ _ ___________________ __ 7 33.2 19.3 1.7 5.7 8 32.5 20.0 3.3 1.5 9 Z6.2 21.0 4.3 12.3 Examples 7-9 illustrate that incorporation o~ a non reactive sodium salt of a strong or wea~ acid into the starting mixture prevents gelation of the reaction mixture when the ODS salt forming reaction is conducted at temperatures greater than 75C or when the molar 2 ~
ratio of calcium hydroxide to malate and maleat~
greater than 1. ol to 1. 2 .
Claims (15)
1. A process for the preparation of a compound of
2,2'-oxydisuccinic acid, said process comprising:
(i) forming an aqueous mixture comprising:
(a) a malate moiety, (b) a maleate moiety, and (c) an alkaline earth metal hydroxide, wherein the mole ratio of c:(a+b) is from 1.01:1.0 to 1.2:1.0; and (ii) reacting said aqueous mixture by heating at a temperature not greater than 75°C for at least 5 hours to form a reaction product in which gelation of said aqueous mixture is substantially minimized and which contains said compound of 2,2'-oxydisuccinic acid.
2. A process as recited in claim 1 wherein the reaction temperature for step (ii) is at least 40°C.
(i) forming an aqueous mixture comprising:
(a) a malate moiety, (b) a maleate moiety, and (c) an alkaline earth metal hydroxide, wherein the mole ratio of c:(a+b) is from 1.01:1.0 to 1.2:1.0; and (ii) reacting said aqueous mixture by heating at a temperature not greater than 75°C for at least 5 hours to form a reaction product in which gelation of said aqueous mixture is substantially minimized and which contains said compound of 2,2'-oxydisuccinic acid.
2. A process as recited in claim 1 wherein the reaction temperature for step (ii) is at least 40°C.
3. A process as recited in claim 1 wherein said maleate moiety is selected from the group consisting of maleic anhydride, maleic acid and mixtures thereof.
4. A process as recited in claim 1 wherein said malate moiety is malic acid.
5. A process as recited in claim 1 wherein said alkaline earth metal hydroxide is calcium hydroxide.
6. A process as recited in claim 1 wherein the mole ratio of a:b is from 1:5 to 1:1.
7. A process for the preparation of a compound of 2,2'-oxydisuccinic acid, said process comprising:
(i) forming an aqueous mixture comprising:
(a) a malate moiety, (h) a maleate moiety, (c) an alkaline earth metal hydroxide, and (d) a non reactive alkali metal salt of a strong or weak acid, wherein the mole ratio of c:(a+b) is from 1.01:1.0 to 2.0:1.0; and (ii) reacting said aqueous mixture by heating at a temperature not greater than 95°C for at least 5 hours to form a reaction product in which gelation of said aqueous mixture is substantially minimized and which contains said compound of 2,2'-oxydisuccinic acid.
(i) forming an aqueous mixture comprising:
(a) a malate moiety, (h) a maleate moiety, (c) an alkaline earth metal hydroxide, and (d) a non reactive alkali metal salt of a strong or weak acid, wherein the mole ratio of c:(a+b) is from 1.01:1.0 to 2.0:1.0; and (ii) reacting said aqueous mixture by heating at a temperature not greater than 95°C for at least 5 hours to form a reaction product in which gelation of said aqueous mixture is substantially minimized and which contains said compound of 2,2'-oxydisuccinic acid.
8. A process as recited in claim 7 wherein the reaction temperature for step (ii) is at least 40°C.
9. A process as recited in claim 7 wherein said maleate moiety is selected from the group consisting of maleic anhydride, maleic acid and mixtures thereof.
10. A process as recited in claim 7 wherein said malate moiety is malic acid.
11. A process as recited in claim 7 wherein said alkaline earth metal hydroxide is calcium hydroxide.
12. A process as recited in claim 7 wherein the mole ratio of a:b is from 1:5 to 1:1.
13. A process as recited in claim 7 wherein said non reactive alkali metal salt of a strong or weak acid is selected from the group consisting of alkali metal chlorides, acetates and xylene sulfonates.
14. A process as recited in claim 13 wherein said non reactive alkali metal salt of a strong or weak acid is selected from the group consisting of sodium chloride, sodium or potassium acetate and sodium xylene sulfonate.
15. The process for the preparation of a compund of 2,2'-oxydisuccinic acid as claimed in claim 1 and substantially as described herein.
THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A process for the preparation of a compound of 2,2'-oxydisuccinic acid, said process comprising:
(i) forming an aqueous mixture comprising:
(a) a malate moiety, (b) a maleate moiety, and (c) an alkaline earth metal hydroxide, wherein the mole ratio of c:(a+b) is from 1.01:1.0 to 1.2:1.0; and (ii) reacting said aqueous mixture by heating at a temperature not greater than 75°C for at least 5 hours to form a reaction product in which gelation of said aqueous mixture is substantially minimized and which contains said compound of 2,2'-oxydisuccinic acid.
2. A process as recited in claim 1 wherein the reaction temperature for step (ii) is at least 40°C.
3. A process as recited in claim 1 wherein said maleate moiety is selected from the group consisting of maleic anhydride, maleic acid and mixtures thereof.
4. A process as recited in claim 1 wherein said malate moiety is malic acid.
5. A process as recited in claim 1 wherein said alkaline earth metal hydroxide is calcium hydroxide.
6. A process as recited in claim 1 wherein the mole ratio of a:b is from 1:5 to 1:1.
7. A process for the preparation of a compound of 2,2'-oxydisuccinic acid, said process comprising:
(i) forming an aqueous mixture comprising:
(a) a malate moiety, (b) a maleate moiety, (c) an alkaline earth metal hydroxide, and (d) a non reactive alkali metal salt of a strong or weak acid, wherein the mole ratio of c:(a+b) is from 1.01:1.0 to 2.0:1.0; and (ii) reacting said aqueous mixture by heating at a temperature not greater than 95°C for at least 5 hours to form a reaction product in which gelation of said aqueous mixture is substantially minimized and which contains said compound of 2,2'-oxydisuccinic acid.
8. A process as recited in claim 7 wherein the reaction temperature for step (ii) is at least 40°C.
9. A process as recited in claim 7 wherein said maleate moiety is selected from the group consisting of maleic anhydride, maleic acid and mixtures thereof.
10. A process as recited in claim 7 wherein said malate moiety is malic acid.
11. A process as recited in claim 7 wherein said alkaline earth metal hydroxide is calcium hydroxide.
12. A process as recited in claim 7 wherein the mole ratio of a:b is from 1:5 to 1:1.
13. A process as recited in claim 7 wherein said non reactive alkali metal salt of a strong or weak acid is selected from the group consisting of alkali metal chlorides, acetates and xylene sulfonates.
14. A process as recited in claim 13 wherein said non reactive alkali metal salt of a strong or weak acid is selected from the group consisting of sodium chloride, sodium or potassium acetate and sodium xylene sulfonate.
15. The process for the preparation of a compund of 2,2'-oxydisuccinic acid as claimed in claim 1 and substantially as described herein.
THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A process for the preparation of a compound of 2,2'-oxydisuccinic acid, said process comprising:
(i) forming an aqueous mixture comprising:
(a) a malate moiety, (b) a maleate moiety, and (c) an alkaline earth metal hydroxide, wherein the mole ratio of c:(a+b) is from 1.01:1.0 to 1.2:1.0; and (ii) reacting said aqueous mixture by heating at a temperature not greater than 75°C for at least 5 hours to form a reaction product in which gelation of said aqueous mixture is substantially minimized and which contains said compound of 2,2'-oxydisuccinic acid.
2. A process as recited in claim 1 wherein the reaction temperature for step (ii) is at least 40°C.
3. A process as recited in claim 1 wherein said maleate moiety is selected from the group consisting of maleic anhydride, maleic acid and mixtures thereof.
4. A process as recited in claim 1 wherein said malate moiety is malic acid.
5. A process as recited in claim 1 wherein said alkaline earth metal hydroxide is calcium hydroxide.
6. A process as recited in claim 1 wherein the mole ratio of a:b is from 1:5 to 1:1.
7. A process for the preparation of a compound of 2,2'-oxydisuccinic acid, said process comprising:
(i) forming an aqueous mixture comprising:
(a) a malate moiety, (b) a maleate moiety, (c) an alkaline earth metal hydroxide, and (d) a non reactive alkali metal salt of a strong or weak acid, wherein the mole ratio of c:(a+b) is from 1.01:1.0 to 2.0:1.0; and (ii) reacting said aqueous mixture by heating at a temperature not greater than 95°C for at least 5 hours to form a reaction product in which gelation of said aqueous mixture is substantially minimized and which contains said compound of 2,2'-oxydisuccinic acid.
8. A process as recited in claim 7 wherein the reaction temperature for step (ii) is at least 40°C.
9. A process as recited in claim 7 wherein said maleate moiety is selected from the group consisting of maleic anhydride, maleic acid and mixtures thereof.
10. A process as recited in claim 7 wherein said malate moiety is malic acid.
11. A process as recited in claim 7 wherein said alkaline earth metal hydroxide is calcium hydroxide.
12. A process as recited in claim 7 wherein the mole ratio of a:b is from 1:5 to 1:1.
13. A process as recited in claim 7 wherein said non reactive alkali metal salt of a strong or weak acid is selected from the group consisting of alkali metal chlorides, acetates and xylene sulfonates.
14. A process as recited in claim 13 wherein said non reactive alkali metal salt of a strong or weak acid is selected from the group consisting of sodium chloride, sodium or potassium acetate and sodium xylene sulfonate.
15. The process for the preparation of a compund of 2,2'-oxydisuccinic acid as claimed in claim 1 and substantially as described herein.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US44690689A | 1989-12-06 | 1989-12-06 | |
| US446,906 | 1989-12-06 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2030985A1 true CA2030985A1 (en) | 1991-06-07 |
Family
ID=23774276
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2030985 Abandoned CA2030985A1 (en) | 1989-12-06 | 1990-11-30 | Process for the preparation of 2,2'-oxydisuccinate |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2030985A1 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5466868A (en) * | 1994-10-14 | 1995-11-14 | Lever Brothers Company, Division Of Conopco, Inc. | Process for the preparation of an enriched 2,2'-oxydisuccinate reaction mixture by removal of calcium malate |
| US5466875A (en) * | 1994-10-14 | 1995-11-14 | Lever Brothers Company, Division Of Conopco, Inc. | Process for the purification of alkaline earth metal salts of 2,2'-oxydisuccinate by acidification |
| US5712243A (en) * | 1994-12-02 | 1998-01-27 | Lever Berothers Company, Division Of Conopco, Inc. | Intimate admixtures of salts of 2,2'-oxydisuccinate (ODS) with selected glycolipid based surfactants to improve the flow and handling characteristics of the (ODS) salt |
-
1990
- 1990-11-30 CA CA 2030985 patent/CA2030985A1/en not_active Abandoned
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5466868A (en) * | 1994-10-14 | 1995-11-14 | Lever Brothers Company, Division Of Conopco, Inc. | Process for the preparation of an enriched 2,2'-oxydisuccinate reaction mixture by removal of calcium malate |
| US5466875A (en) * | 1994-10-14 | 1995-11-14 | Lever Brothers Company, Division Of Conopco, Inc. | Process for the purification of alkaline earth metal salts of 2,2'-oxydisuccinate by acidification |
| US5712243A (en) * | 1994-12-02 | 1998-01-27 | Lever Berothers Company, Division Of Conopco, Inc. | Intimate admixtures of salts of 2,2'-oxydisuccinate (ODS) with selected glycolipid based surfactants to improve the flow and handling characteristics of the (ODS) salt |
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