SUCCINIC ACID DERIVATIVES

This invention relates to succinic acid derivatives and to their use as detergent solvents and as plasticisers for resins.

Applicant's Canadian Patent Number 974,544, issued February 25, 1975 describes and claims certain carboxymethyl- oxysuccinic acid salts, that is salts of the acid having the formula H H00C - C - H H I i H00C - C - H H - C - C00H and detergent compositions containing them.

The patent also describes and claims detergent composi¬ tions containing oxydisuccinic acid salts as builders.

Furthermore the patent describes and claims detergency builders being certain salts of acids of the formula R1 - CH - (CH-)= - Z - (CH-), - C = ÇH I z a £ d i j X COOH COOH or 2 3 IT R-3 R1 - CH - (CH2)a - Z - (CH2)b - C C - H X COOH COOH in which R is hydrogen, C, .,_ alkyl, C1_14 hydroxyalkyl or car- boxyl X is carboxyl, sulphuric or sulphonic acid a is zero, 1 or 2 -Z- is an -0-, -S-, -NH- or -NR4- linkage, R4 being C,.

alkyl or hydroxy alkyl b is 0 or 1 and R and R are, individually, hydrogen, methyl and carboxy- methyl C. 644 providea that when -Z~ is -0-, a is zero, X is carlDoxyl and provided that R is other than hydrogen when. R2 and R3 are hydrogen and b is zero.

According to the present invention there is provided a compound of the general fornrula R5- CH - 0 - (CH2)b - CH — CHR1 COOR1 ooorj r C00Ro COOR2 in which R is hydrogen or methyl; R , R and R are individually straight or branched chain C1_12 alkyl groups, benzyl groups or cyclohexyl groups; R is hydrogen, methyl or ethyl; and b is zero or 1.

In a more limited aspect of this invention -there is provided a compound of the general formula R5 - CH - 0 - '(CEL). - CH CHR1 I J | COOR4 COOR3 COOR2 in. which R is hydrogen or methyl; R , R and R are individually straight or branched chain c1_12 alkyl groups, benzyl groups or cyclo¬ hexyl groups; g R is hydrogen, methyl or ethyl; and b is zero or 1 ; provided that when R2, R3 and R4 are all ethyl, R1 and R5 are not both hydrogen when b is zero.

We have discovered that these succinic acid derivatives are useful as plasticisers for synthetic plastics substances.

Accordingly in an aspect of this invention there is .provided a plastics composition containing a compound falling ' within the broad general formula set out above as a plasticiser.

The compounds are particularly useful for plasticising polyvinyl-' chloride.

_,-. ' ' C.644 We have also discovered that these sticcinic acid derivatives are useful as detergent solvents in detergent compositions.

Accordingly in a iurther aspect of this invention there is provided a detergent composition containing a compound falling within the broad general formula set out above as a •detergent solvent.

The detergent compositions containing the new detergent solvents are particularly useful for removing oil based stains of polyester and polyester blend fabrics.

The compounds of the present invention may be prepared by the condensation of glycollic acid, or an alkylated glycollic acid with maleic anhydride or maleic acid or an allcylated derivative thereof, followed by esterification of the resultant acid or salt. Generally the reaction may be represented as R5 - CH - OHi 1COOH R5 - CH - 0| COOH + H.(CH0), - C — CR 2b, CO CO 2b, , COOH COOH where R , 11° and b are as defined above.

Thus if an ester of carboxymethyloxysuccinic acid (R = R = H, b = 0) is required, then the components used in the condensation reaction will be glycollic acid and maleic anhydride.

Esters of acids in which R and R0 are other than hydrogen may be obtained by using the appropriate alkylated component for the condensation reaction. Thus if an ester in accordance with the invention in which It is methyl is required, methyl maleic acid and not maleic acid is used. Similarly if is required to be methyl, lactic acid, and not glycollic acid is used.

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r5 C.644 103080 Esters of acids in which h = 1 may he prepared hy using itaconic acid instead of maleic acid in the condensation reaction.

The method of preparing the acid or salt precursors of the present invention will now he desorihed in the following example. Althoxigh this example relsfces to the preparation of the sodium and calcium salts of carhoxymethyloxy- succinic acid from maleic anhydride and glycollic acid, the method is applicahle generally to the preparation of the other acid and salt precursors and will he readily applied to these compounds hy those skilled in the art.

Example 1 Maleic anhydride (0.2 mole; 19.6 g) was dissolved in water (100 ml) at room temperature and stirred for 10-15 minutes to convert it to the acid. Glycolic acid (0.24 mole; 18.3 g) was then added and dissolved xvith stirring. Calcium hydroxide, (ca 0.36 mole; 27 g)j sufficient to attain a pH of 11.4 as measured initially at 250C was added next while stirring the reaction mixture vigorously. The mixture was heated to reflux and maintained at reflux for two hours while stirring vigorously. After cooling to 600C, finely ground sodium carhonate (0.4 mole; 42.4 g) was added and stirring was continued for fifteen minutes at 60oC. The mixture was then cooled to room temperature and the suspended calcium carbonate filtered off and washed with water. The filtrate (including the washings) contained the product," trisodium carhoxymethyl oxysuccinate, in yields of ahout 95ù/o as determined hy NMR analysis.

Anhydrous trisodium carhoxymethyloxysuccinate may he isolated hy evaporation of the filtrate and drying of the residue.

- C. 644 Alternatively, the filtrate may be treated with alcohol or acetone to precipitate the desired trisodium carboxy- methyloxys-uccinate which is then isolated by filtration and further dried to remove any water of hydration if desired.

Further purification may be accomplished by recrystallisation In preparing the esters of carboxymethyloxysuccinic acid either trisodium carboxymethyloxysnceinate prepared as in Example 1 or the calcium salt of carboxymethyloxysuccinic acid may be used. The calcium salt is readily obtained by filtration of the reaction mixture of Example 1 after the two hour reflux period. The dry calcium salt has the empirical formula c12Hio014Ca3• Since water is removed in the esterification reactions, iS the starting sodium or calcium salts of carboxymethyloxysuccinic acid may be used in the form of their hydrates.

From the trisodium and calcium salts, C., to C. alkyl esters of carboxymethyloxysuccinic acid may be prepared by the following method which is generally applicable.

Example 2 A mixture of 103 g (0.4 mole) of trisodium carboxymethyl- oxysuccinate or 0.2 mole of the calcium salt of carboxymethyl¬ oxysuccinic acid, 3.6 moles of the desired alcohol (methanol, ethanol, etc.), 360 ml of ethylene dichloride and 45 ml of concentrated H2S04 was stirred and refluxed for 13 hours. The precipitated sodium (or calcium) sulfate was filtered off and the filtrate washed repeatedly with saturated sodium bicarbonate solution followed by water until the washings were of neutral pH. The ethylene dichloride layer was then dried and evaporated to give a residue of ester which was finally distilled in vacuo.

In this way the following esters of carboxymethyloxysuccinic acid were obtained:

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trimethyl triethyl tri-n-propyl tributyl C.644 h . p . 0C/mni Similarly, Cg to Cl2 alkyl esters of carboxymethyloxy- succinic acid may be prepared by the following methods which are generally applicable.

Example 3 A mixture of 25.8 g (0.1 mole) of the sodium salt or 0.05 mole of the calcium salt of carboxymethyloxysuccinic acid, 0.9 mole of the desired alcohol (e.g. n-pentyl, n-hexyl 2-ethyl- hexyl, etc), 100 ml of ethylene dichloride and 12 ml of con¬ centrated sulfuric acid was stirred and refluxed for 30 hours.

The precipitated sodium (or calcium) sulfate was filtered off and the filtrate mixed with 400 ml of ether. The ether/ethylene dichloride layer is then washed repeatedly with saturated sodium bicarbonate solution and water until the washings were of neutral pH, The organic layer was then dried and evaporated to yield a residue which was partially distilled (oil bath to 140 C) at 0.1 mm to remove imreacted alcohol. In this way the following esters of carboxymethyloxysuccinic acid were obtained in approximately 90% yields and in purities of 85-95% as determined by NMR analysis: tri-n-pentyl, tri-n-hexyl, tri-n- octyl, tri(2-ethylhexyl), tri-n-decyl and tri-n-dodecyl.

Mixed alkyl esters may be prepared by utilising a mixture of the desired alcohols in the above examples. Alternatively, another method of preparing the higher esters (homogeneous and mixed) is as follows:

Example 4 A mixture of 160 g (l.l mole) of a commercial synthetic alcohol containing about 45% 1-octanol and 55% i-decanol, 85 g - 7 C.644 (0.33 mole) of trisodium carboxymettiyloxysuccinate and 100 ml of toluene were placed in a flask, and 57 g of concentrated sulfuric acid was added slowly with stirring. The mixture was then heated to reflux and water was continuously removed using a Dean and Stark apparatus. The toluene layer in the distillate was continuously returned to the reaction flask.

When no more water distilled over, the reaction mixture was cooled to ahout 50 C, filtered to remove insoluhle salts and then washed repeatedly with saturated sodium bicarbonate solution followed by water until the washings were of neutral pH.' The organic layer was then stripped of solvent and other volatiles by heating gradually to 140oC under a pressure of- 0.1 mm. The residue, which consists of a random mixture of Cg-C,0 alkyl esters of carboxymethyloxysuccinic acid, was finally decolorised by treatment with 0.1 by weight of activated carbon at 90oC for one hour followed by filtration.

The procedure of examples 3 and 4 is applicable to benzyl and cyclohexyl esters also.

The esters of the invention can be tised as plasticisers with a variety of plastics, for example polyvinyl chloride, polyvinyl chloride copolymers, polyamides such as nylon~6 and nylon 6,6, polyethylene, polypropylene, polystyrene, polyesters such as polyethylene terephthalate, polyurethanes, polycarbonates, polyacrylates, polyacrylonitrile, polytnethacrylate, phenolic resins, epoxy resins, cellulose nitrate cellulose acetate and ethyl cellulose. The esters have a lower volatility than the normal plasticisers used in the art and the precursor acids and salts are non-toxic, non-teratogenic and biodegradable under both aerobic and anaerobic conditions. The latter features a/re important since plasticisers eventually find their way into the environment (or into contact with humans or their food) and ester type plasticisers gradually release to the C . 644 environment, the precursor acid or salt and the starting alcohol hy chemical or bacterial action.

Preferred compounds for use as plasticisers are the esters derived from C to C, alcohols, most notably the esters of 1) carhoxymethyloxysuccinic acid, 2) lactoxysnccinic - acid, 3) carhoxymethyloxymethylsuccinic acid, and 4) oC-carboxy- methyloxy- /?-methylsuceinic acid. The trihutyl-tri(isohutyl)-, tripentyl-, trihexyl-, tricyciohexyl-, triheptyl-, trioctyl-, tri(2-ethylhexyl)-, tri(isoctyl)-, tri(mixed hexyl/octyl-), trinonyl-, tridecyl-, tri(isodecyl)-, tri(mixed n-octyl/n-decyl-), trixindecyl-, tridodecyl-, and tribenzyl esters of these acids are most preferred.

Levels of xise of the esters of the present invention as plasticisers are of the order of 1 to 75 weight percent, based on the weight of the total composition, with a preferred range of from 15 to 65 weight percent. The following example illustrates the use of an ester in accordance with the invention as a plasticiser for plastics.

Example 5 v Tri(2-ethylhexyl) carboxymethyloxysuccinate was added as a plasticiser in the preparation of polyvinyl chloride (PVC) film having the following formulation:

Parts hy Weight S-PVC resin (K value, 68-72) 100 plasticiser 6£ stabiliser 2 wax lubricant 0.5 Using a mixing roller at 170° (7 min.) followed by post-pressing the film at '1700C under contact pressure for 2 minutes, a good plasticised film (1.3 mm) of polyvinyl chloride was obtained..Cold resistance was -390C compared to -360C for a control PVC film made using di-2-ethylhexyl phthalate (DOP) as the plasticiser.

"" C.644 These esters also have utility as detergent solvents in. detergent compositions particularly for oil and grease type stains on polyester and polyester blend fabrics.

Detergent compositions according bo the invention will generally include a synthetic builder and a water soluble .. organic detergent compound. Detergent compounds useful in the present invention are the anionic (soap and non-soap), nonionic, zwitterionic and arapholytic compounds. The general 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. Typical of such detergents are those described in the well-known books entitled "Surface Active Agents" by Schwartz and Perry and "Surface Active Agents and Detergents" by Schwartz, Perry and Berch, both by Interscien.ee Publishers, New York, New York, the disclosures of which are incorporated by reference herein.

The esters of the present invention can also be used with a wide variety of builder compounds such as sodium tripoly- phosphate, sodium carbonate, sodium silicate, the alkali metal, ammonium and substituted amraoniutn salts of oxydisuccinic acid, oxydiacetic acid, carboxymethyloxymalonic acid, carboxymethyl- oxysuccinic acid, lactoxysuccinic acid, citric acid, mellitic acid, tetrahydrofurantetracarboxylic acid, polyacrylic acid, nitrilotriacetic acid, oxidised starches and mixtures thereof.

The preferred esters for use as detergent solvents are those derived from staright or branched chain. 2-6 carbon alcohols. Levels of use are of the order of from 1 to 35 weight percent based on the weight of the total composition, with a preferred range of from 2 to 20 weight percent and a most preferred range of from 2 to 10 weight percent.

C. 644 Use of the esters of invention as detergent solvents is illustrated in the following examples.

Example 6 Four polyester/cotton (65-35) Khaki permanent press (trouser weight) test pieces (4 l/2" x 6") were first soiled by adding 3 drops of dirty crankcase motor oil on the center of the cloth and the stain allowed to set for one hour. The test cloths were then washed in the Terg-O-Tometer at 120 P, using water of 180 ppm (2:1 Ca++/Mg++) hardness, and 90 cycles per minute agitation, with a 5 solution, of the detergent product described below (i.e. 50 g/liter) for 15 minutes and then hand squeezed to remove excess water. Finally the cloths were given a 20 minute wash at the standard level of use (e.g. 0.144$) under the same conditions followed by a one minute rinse. After drying the washed cloths, the degree of stain removal is rated visually according to the system below:

Visual Grading System 0 = Complete removal 1 = Very slight remaining stain.

2 = Slight remaining stain 3 = Moderate stain removal 4 = Poor stain removal = Very poor stain removal 6 = Equal to original stain (The above laboratory procedure has been, found to correlate with the regular procedure used by housewives whereby a paste of the product is applied to the spot prior to washing the fabric in the washing machine.) The detergent product used was formulated as follows:

C. 644 Component o/0 by weight Tergitol 15-S-9 (addnct of nine moles 15.0 of ethylene oxide per mole of random secondary alcohol derived from C,,-C,_ paraffins) •,-5 Sodinm Tripolyphosphate 40.0 Sodium Carboxymethylcellulose 0.3 RU Silicate Solids (Si02:N"a20 ratio of 2.4:1) 4.2 Miscellaneous (mainly fluorescent dyes, 0.6 colourants, perfume) "Detergent Solvent" 4.0 Silica absorbent for detergent solvent 3.0 Water 12.0 Sodium sulfate balance Ten such formulations using the following "Detergent Solvents" were prepared and evaluated as described above:

A - dibutyl phthalate (control) B - trimethyl carboxymethyloxysuccinate C - triethyl carboxymethyloxysuccinate D - tripropyl carboxymethyloxysuccinate E - tributyl carboxymethyloxysuccinate F - trihexyl carboxymethyloxysuccinate G - tri(2-ethylhexyl) carboxymethyloxysuccinate H - trioctyl carboxymethyloxysuccinate I - tridecyl carboxymethyloxysuccinate J - tridodecyl carboxymethyloxysuccinate The results obtained using the visual grading system were as follows:

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C.644 Sample Visual Code Grading Code A 2 B 2 C 1 D 1 E F 1 G 2 H 2 I .2 J 2 .

The table clearly shows that the esters according to the present Invention are equal to and in some instances superior to dibutyl phthalate which is considered to he the standard for detergent compositions of this type.

Example 7 Other suitahle formulations with the "Detergent Solvent" being the same as in Example 6 are as follows:

Component LAS (sodium linear secondary alkyl (C10-C15) benzene sulfonate) Sodium tripolyphosphate Sodium carboxymethylcellulose RU silicate solids Miscellaneous (mainly fluorescent dyes, colourants, perfume) "Detergent Solvent" Silica absorbent for detergent solvent . Water Sodium sulfate "fo by weight 0 .3 o 6 15. 0 6. 0 12. 0 balance C.644 Example 8 Component o/0 by weight LAS 28.0 Trisoditini citrate 35.0 Sodium carboxymetlrylcellulose 0.3 RU silicate solids 8.0 Miscellaneous (mainly fluorescent dyes, 0.6 colourants, perfume) "Detergent Solvent" 10.0 Silica absorbent for detergent solvent 5.0 Water 10.0 Sodium sulfate balance Example 9 Component LAS Tri sodium carboxymethyloxysuccinate Sodium carboxymethylcellulose RU silicate solids Miscellaneous (mainly fluorescent dyes, colourants, perfume) "Detergent Solvent1' Silica absorbent for detergent solvent Water Sodium sulfate Example Component LAS Tri s od ium carb oxyme thy1oxysu c c in at e Sodium carboxymethylcellulose ru silicate solids Miscellaneous (mainly fluorescent dyes, colourants, perfume) "Detergent Solvent" Wat e r Sodium sulfate % by wei Kht .0 .0 0 .3 4 .0 0 .6 7 .0 4 .0 .0 balance c/o by wei fiht .0 .0 0 .3 balance 103098© C. 644 2 .0 6 .0 9 .0 0 .3 0 .6 lance Example 11 Component t/0 by weight Tergitol 15-S-9 30.0 Triethanolamine Neodol 25-3E0 sulfate 10.0 (the triethanol amine salt of the sulfated adduct of 3 moles of ethylene oxide per mole of Neodol 25 which is a mixture of linear primary alcohols containing 12-15 carbon atoms) Coconut monoethanolamide "Detergent Solvent" Ethanol Sodium carboxymethylcellulose Miscellaneous (mainly fluorescent dyes, colourants and perfume) Water The lower volatility of the esters relative to ditvutyl phthalate is especially advantageous since little or no loss of the ester occurs during processing of the detergent powder. A further advantage is that should any of the ester hydrolyse during detergent processing or during the washing process, the resultant salt is an excellent detergent builder, whereas in the case of the phthalate salt no useful detergent properties are obtained. The non-toxic and biodegradable properties of the precursor acid from which the esters are derived are especially important since detergent wastes are generally discharged directly into the water environment,.

The esters can. also be used in spot cleaners or pre-wash spot cleaners of the spray or aerosol type.

Thus, a 5 to 10$ by weight solution of the desired ester Mark) ll/Freon 12 propellants is admirably suitable for dispensing from an aerosol container for spot cleaning of — 15 — / * • • C. 644 fabrics, especially polyester, polyester blends and other synthetics and also as a pre-wash spot cleaner for such fabrics prior to washing the fabric in a washing machine with a conventional laundry detergent formulation (phosphate or non-phosphate based).

- 16 ~ *** PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS 1' A compound of the general formula R - CH - O - (CH2)b - CH - CHR1 COOR4 COOR3COOR2 in which R is hydrogen or methyl; R and R are mdivid chain C1_12 alkyl groups; T>2 O3 J 4 k , R and R are individually straight or branched R is hydrogen, methyl or ethyl; and b is zero or 1.

A compound of the general formula R - CH - 0 - (CH,). - CH - CHR1 COOR4 COOR3COOR2 in which R is hydrogen or methyl; R , R and R are individually straight or branched chain C1_12 alkyl groups; R is hydrogen, methyl or ethyl; b is zero or 1 provided that when R2, r3 and R4 are all ethyl and R1 and R5 are not both hydrogen when b is zero.

,4 A compound according to claim 2 in which R2, R3 and R are C4-C12 alkyl groups.

.4 A compound according to claim 3 in which R2, r3 and R*1 are each butyl, isobutyl, pentyl or hexyl groups.

5- A compound according to claim 3 in which R2, r3 and