DE1745236C - Process for the partial decarboxylation of a polymeric carboxylic acid - Google Patents

Description

The invention relates to a process for the partial decarboxylation of polymeric carboxylic acids.

Of the polymeric acids are polyitaconic acid itself as well as other closely related compounds, such as those described in U.S. Patent 3,055,873 in U.S. Patent No. 3,055,873 Techniques are known and have a variety of different uses, but they have been proven has never been used as a chelating agent. According to the present invention, it was found to be possible to partially decarboxylate polyitaconic acid and other similar compounds, so new ones Polymers are obtained which have this desired property, i.e. H. the chelating function. This fact is surprising when one considers that both the structurally related Both polyacrylic acid and polymethacrylic acid are completely different under the same conditions behavior.

According to the process according to the invention, a polymeric carboxylic acid, (1) polyitaconic acid, (2) a copolymer of itaconic acid with at least 10 mol percent itaconic acid and up to 90 mol percent of an acidic copolymer with a polymerizable A./J double bond on a carboxylic acid clump or (3 ) a mixed polymer of itaconic acid "" with at least about 30 mol percent itaconic acid up to about 70 "mol percent eircs non-acidic mixed monomers with a polymerizable double bond is heated to an elevated temperature with the formation of carbon dioxide. Suitable starting materials for the reaction are all polyitaconic acid itself, As already mentioned above, for example the above-mentioned copolymers of itaconic acid with up to about 90 mol percent acrylic acid or methacrylic acid as well as those made from itaconic acid with up to about 70 mol percent styrene, acrylonitrile, methacrylonitrile, lower alkyl acrylic acid, lower alkyl methacrylates and mixtures of these monomers formed become T. In general, the method consists in heating the polymeric acid in an aqueous medium until carbon dioxide gas is evolved; is almost complete, so that in practice up to / ■ about 30 mol percent carbon dioxide per mol equivalent of itaconic acid unit is developed in the polymer. Although certain chdaib-forming functions h.-i less than about 5 mole percent escaped carbon dioxide per itaconic acid unit in the polymer of the pol ·. If the desired effect is to be achieved in a convincing manner, it is generally not advisable, or at least not preferable, to go below this value. For example, in F; 'of those copolymers which renate with non-acidic substances, such as, for example, styrene. Acrylonitrile and the like are formed, generally less and differently. Amount of carbon dioxide per unit of itaconic acid on the same basis as above. The temperature required for Umsetzui-.c is preferably in the Berek! _: between 60 and about 160 ° C, so that about 5 hours; -30 mole percent carbon dioxide on the above; Develop base while heating. D> -_ reaction is preferably carried out in an aqueous :; Medium among acidic, neutral or basic; ' Reaction conditions carried out, and if this occurs : use base to accelerate the reaction; is, such an amount is usually used by which the above-mentioned decarboxylieru "product, which is still some free CaiDoxylgruppen ent hall., is only partially neutralized. In any case, should the upper limit, the neutralization preferably about 80 / not exceed ° _0th The The desired product is easily separated off from the reaction mixture therein by customary measures, such as, for example, by freeze-drying.

Through the decarboxylation process according to the invention, chromophoric groups are introduced into the polymeric starting compounds which absorb in the UV region of the spectrum at about 283 πψ. At the same time, chelal biliary functions begin to show in the polymer, which is simply demonstrated by the δο positive ferric chloride enol test (purple color), which is negative for non-decarboxylated polymers. The optical density at the wavelength of the absorption maximum, expressed as El «, ie the optical density of a 1% solution 1 cm thick, is a simple measure of the extent of decarboxylation and introduction of chelating groups in those polymers in which other ultraviolet absorbents himself

do not interfere with repetitive units. A llomopohmeres \ on itaconic acid, ie polyitaconic acid. which was partially decaroxylated as far as possible under the conditions of the conversion according to the invention. has an optical density E-; '; \ on about 4 * 5 to 50. L fully partially decarboxvlierie polvilaeonic acid and fully or incompletely partially decarboated copolymers of itacnic acid misnomeric monomers have a density E';'.'.on about 0 to 45 to 50. and also at u about Z! S3 πιμ.

Products that can be manufactured according to the invention have different purposes depending on the type of polygons in which jiat-forming groups are present. . , ". acid after de-arbouling in 1-orm of your Λ! '. ^ metal salts to stabilize other Po! \; v, en: ri. v.:; B. Ρολ (inyl chloride or Pol ;, prcpsl'jn. at ( JL · ■ "■ - traces of heavy metal ions, such as iron .v- ■ brave, otherwise the decomposition of the same kaui ^h s-:. ■■ could. On the other hand, MiM / hpoU-p.ie: · - ' ml a Ciehalt 5-0 "" itacousäure na.- ler decarboxylation for producing \ on Überzu- by the chelatbüduidcn viruppen selbs:.. are crosslinked mn '' ■ polyvalent metal ions ^i% u Ar "? Kirn- and alkali metal salts of Partially decarbov; ieu polymers which have been prepared from 15 to HX) ⁰ ,., itaconic acid and ■ 'Ins 85 °', Latex paints which partially decar'.iox> lier: o PoKiiaeoiisäure. Which are

forms when polyitaconic acids are not followed by the ingenious decarboxylation process until the end of the process ;; ' the development of carbon dioxide gas unierwori ::! is, eir.e still acidic organic compound .iiig. those with a variety of different Me ^; igrimd connections, with ammonia and with ort: μ! see amines salts / u form \ ermag. It is soluble in S \ :: s -,. In an adverse solution, it shows an absorption maximum in the UV range of the spectrum with a characteristic optical density E! '.; only 17 for that particular substance.

In summary, it should be said that the present invention those partially decarboxylated copolymers and polymeric acids which form from polyitaconic acid itself, those from interpolymers of itaconic acid containing at least 10 mole percent itaconic acid and up to about 90 mole percent polymerizable units with

η double bonds of monomers of the structure CW, - CR ₁ R ₂ , where R _{1 is} a hydrogen atom or a Meihvi group and R _{2 is} a carboxyl radical. as well as those of copolymers of itaconic acid with a content of at least about 30 mol

', Percent itaconic acid up to about 70 mole percent polymerizable units with double bonds of monomers of the structure CH., = CR ₁ R ₂ , in which R _{1 is} a hydrogen atom or a Meihvi group and R _{2 is} a carbalkoxy group with 1 to 4 carbon atoms in the alkyl group. a cyano or a phenyl group means' and R ₁ always means a hydrogen atom when R 1 means a phenyl group. The term polyitaconic acid and the associated copolymers and polymeric acids, as mentioned above, mean those polymers and copolymers which contain 10 to 100% itaconic acid and a Brookfield viscosity between 10 and 100 (XX) cP at 25 C than 25 ° / _o solution in Wn ^ have he or dioxane.

The following examples serve to further illustrate the invention.

example 1

ss in a 2-1 three-necked round bottom flask with reflux condenser, mechanical stirrer and an immersion thermometer 500 g (3.85 mol) of refined itaconic acid were placed in 1000 ecm of water (the latter 1st stage required heating the aqueous mixture first on a steam bath). Then stirring started, the temperature of the reaction mixture became adjusted to 70 "C, and 5.4 g (0.5 mole percent) potassium persulfate were added. The resulting Mixture was then left on for 29 hours

see wavelength of about 283 11m. where 45 is heated to about 65 ° C (by an oil bath of 70 ¹ C). To

48.6, and when dissolved in 0.0 In NaOH of about 312 ma, where E ¹ ^ _n - 74.5. The salts it forms with metals include the salts of alkali metals, such as sodium and

over this period an additional 2.7 g (0.25 mole percent) potassium persulfate was added and heating continued for another 18.5 hours. After that, i.e. after 47.5 hours, the bromine number analysis in one

p
Potassium, the alkaline earth metals, such as. B. calcium, 50 sample that only 9.5 ° / ₀ of the originally called from

Magnesium and barium, and heavy metals such as B. of iron, copper and zinc. To the salts that it forms with organic amines include those formed from water-soluble lower alkyl amines raw material used itaconic acid in the mixture templates. A 2 (X) g sample of the aqueous polymer solution was then slowly poured into 2 liters of cold Poured acetone, and the polymer fell out of the

y g

like the lower alkanolamines, for example 55 solution in the form of fine granules. It was ßer pyridine also ethylenediamine and triethylamine suction filtered and twice again from aqueous acetone

besides pyridine also ethylenediamine and triethylamine. Other partially decarboxylated polyitaconic acids are according to the invention by partial decarboxylation of copolymers of itaconic acid according to the obtained above description. For example, a product was made by decarboxylating a Copolymers obtained from itaconic acid with an equimolar amount of acrylic acid, d. that is, the weight ratio of the reaction parts is sucked off and reprecipitated twice from aqueous acetone. The fluffy one obtained in this way white powder was then washed with more fresh acetone and air dried to give a Product was obtained which was then dried in a vacuum oven at 55 ° C and 20 mm Hg pressure would. In this way there was obtained solid polyitaconic acid which, after 64 hours in one Vacuum desiccator over phosphorus pentoxide and then

was 1.8: 1.0. The obtained, partially de- 65 5 hours in a Fischer drying tube at 56 ° C and carboxylated polymeric acid also shows that 0.1 mm Hg had been left to stand at a constant Weight had been dried. This product gave no color with ferric chloride solution

absorption maximum in the UV range of the spectrum at a wavelength of about 2Ki mu. however, the

745 236

soluble in water and insoluble in acetone and had the following characteristic properties: /. ¹ ^ l = 282nm (E !!;. = 4.7); Brookfield viscosity. Spindle No. 2. ' 30 rev / min. at 25 C 126 cP (J8 ⁿ , _o ige aqueous solution).

Analysis for (C ₅ H ₆ O ₄ ):

Calculated . .. C 46.2, H 4.65:

Found ... C 47.2, H 5.15, bromine number 1.5.

Example 2

13 g of polyitaconic acid (prepared according to Example 1 from refined itaconic acid) were placed in a 100 cc round bottom flask with a cooling condenser and gas outlet tube, which was connected to the open end of the condenser and protruded into an inverted cylinder filled with saturated sodium chloride solution ) and given 26 ecm of water. When almost all of the polyitaconic acid had dissolved, the reaction mixture was gradually heated to reflux by means of an oil bath preheated to 125 ° C., and the amount of carbon dioxide gas evolved and collected in the cylinder was measured at various time intervals. It was found. that after 47 hours 650 c: m carbon dioxide had developed and that the reaction was essentially complete. This corresponded to 29 ^u / n of the theoretical value for 1 mole of carbon dioxide per mole of itaconic acid sequestones in the polymer. The half-life for the development of carbon was about 4.5 hours.

20 g of the above-prepared decarboxylic acid polyitaconic acid solution was then diluted with 20 ecm of water and refilled through a glass frit. after having been briefly warmed up beforehand. A portion of the filtrate obtained in this way (15 ecm) was diluted with a further 15 ecm of water, and the sample obtained was freeze-dried. The resulting fluffy, light material weighed 1.8 g and was then dried for a further 20 minutes in an I isher-Troeken tube at 54 ° C. and 0.1 mm Hg pressure. The partially decarboxylated solid polyitaconic acid product gave a red color with cerium chloride solution which was soluble in water (although less than the original polyilaconic acid). Easily soluble in acetone and had the following characteristic properties: /. "," at 283 ημ (E Γ. = - 48.6); z. ¹ ;, ^ NaOH at 316 mn (E |. ^S _m - 74.5).

Analysis:
Found ... C 50.88, H 5.02, bromine number 16.3.

Example 3

A solution of 33.6 g (0.3 mol) of itaconic acid anhydride in 33.6 ecm of benzene with a content of 0.36 g (0.5 mole percent) of benzyl peroxide was added in a nitrogen atmosphere at an oil bath temperature of 75 'C in the same way as in the previous example for the corresponding reaction with ilaconic acid as the starting material. After 96 hours the heating stopped interrupted, -: nd the polymer precipitated from the hot solution was abpenutschl and then partially air-dried. After washing with warm benzene, it was then dried in 100 ecm Dissolved acetone and then slowly poured the solution into 1 liter of chloroform with vigorous scrambling. The ausj precipitated polymers were again filtered off, partially air dried as above and then in one Vacuum oven dried without heating. Fun Driuel this latter sample was then again made from 440 ecm anhydrous acetone-chloroform mixture

ίο (volume ratio 1:10) precipitated, and the sample obtained is finally dried to a constant weight in vacuo over phosphorus oxide and then for about 5 hours in an ice-cream drying tube at 54 ° C. and 0.1 mm Hg. In this way, 28 g (S3'V ₀ ) of solid polyitaconic anhydride were obtained, which was essentially free of any residual monomers pure η.

Analysis for (CH ₄ O ₃ ) ,,:

Calculated ... C 53.56. H 3.59:
found ... C, 53.11. H 4.14.

B e i s ρ i e 1 4

A solution of 11.2g (0.1 mol) polyitaconic anhydride decarboxylation was carried out in the manner described in Example 2 in 28 ecm of water. To solve the total anhydride was required about 20 minutes first, then the procedure was the same as upstairs After 96 hours the Eihit / ung interrupted and collected the precipitated polymer. The product thus obtained became then dissolved in water to form a 5% solution while it was still warm. through a cilas frit funnel Illuminated and with the formation of 6.5 g partially deearboxylated solid polyitaconic acid in Form of fluffy crystalline particles freeze-

4 ". A sample was then dried for an additional 24 hours in an I isher drying tube at 54 ° C. and 0.1 mm Hg Print dried to constant weight and egg gave the following analysis:

Analysis:
Found ... C 50.90, H 5.05, bromine number 23.90.

S "example

The result of a series of attempts which the Effect of acid and base on the decarboxylic process should show, are nacli-

, ',., indicated below. In each "all of which were either 0.02 mol (as Itaconsäurceinheileii) Polyitaconsäiire or 12:02 mol Polyilaconsäurcanhydrid stirring / u 18 ecm an" aqueous solvent mil a temperature of 100 ⁰ C is added in one equipped with a mechanical stirrer and by The flask and its contents were quickly closed and the rate and amount of carbon dioxide gas evolution were measured, the results of which were determined as follows in the polymer):

Tested polymer Aqueous solvent

Half an hour

Amount of CC),

Polyitaconic acid

Polyitaconic acid

Polyitaconic anhydride
Polyitaconic anhydride
Polyitaconic anhydride

distilled water
NaOH, 0.25 mol *
distilled water
6N hydrochloric acid
NaOH, 0.5 mol *

1.30 0.30 1.50

2.0 to 3.0 ** 0.025

0.26

0.30 0.26 0.29

*) Based on 1 mol of itaconic acid cinhitol.

··) is heated from room temperature to 108 ⁰ C. The RückfluBicmpcraiur of the evolution of gas overlying thermal expansion resulted in only approximate Halbwcrtzcitcn.

From the data in the table above it can be seen that that limited amounts of base significantly increase the rate of decarboxylation without the final level of implementation is affected. Add polyitaconic acid to dilute aqueous potassium hydroxide containing 2 moles of potassium hydroxide for 1 mole of itaconic acid unit in the polymer contains no decarboxylation takes place at 58 ° C in 24 hours, which is due to UV absorption of the acidified Solution at 279 ιτιμ was detected. The partial neutralization of the base with concentrated sulfuric acid caused the decarboxylation progress again. The addition of polyitaconic anhydride, on the other hand, is the same amount Base caused essentially complete decarboxylation in the 1 minute required was to mix and withdraw a sample for examination by UV absorption.

Example 6

To a 5 liter, four neck, round bottom flask equipped with a reflux condenser, thermometer, mechanical stirrer, and nitrogen inlet roller, was added 910 grams (7.0 moles) of refined itaconic acid dissolved in 2828 cc of deionized water. The stirrer was then started, heated on an oil bath and 504 g (7.0 mol) of acrylic acid was added to the mixture. The internal temperature was increased to about 50 ⁰ C {. 2 ° C while slowly introducing a stream of nitrogen gas into the heated system. After equilibrium had been established, 18.92 g (0.07 mol) of potassium persulfate were added and the course of the reaction was followed by determining the bromine number. After 31 hours, 15 minutes an additional amount (9.46 g, 0.035 mole) of potassium persulfate was added. The reaction was then continued until a total of 49 hours and 15 minutes had passed (the bromine number analysis after 46 hours, 35 minutes indicated 97% conversion). The haconic acid-acrylic acid mixed polymer obtained in this way showed the following typical physical properties in aqueous solution: Brookfield viscosity with spindle no. 2 and 30 rev / min. at 25 ⁰ C = 97OcP; Specific weight at 15/15 ° C = 1.154: n ™ 1 ° / ₀ - 0.64: n ² ™ 0.33 ⁰ Z ₀ ----- 0.89. The solid polymer can be obtained from the aqueous solution by precipitation with acetone, as described in Example 1 for polyitaconic acid.

Example?

The procedure described in Example 2 was essentially repeated to produce the interpolymer of llaconic acid and acrylic acid, the one after the above Example was obtained (1.8 parts of itaconic acid per 1.0 part of acrylic acid, based on the Ge * weight) partially to decarboxylic, with the difference that 2.0 g of the mixed polymer and 18 ecm Water were used. After about 25 hours had elapsed, decarboxylation was essentially completed (59 cc of evolved carbon dioxide gas was collected), and a partially decarboxylated one was obtained solid copolymer product, the absorption maximum of which is in the UV range of the spectrum was at a wavelength of 283 ΐημ, while the Density EU-17 was. The amount of developed Gas was 26 mole percent carbon dioxide per mole equivalent of itaconic acid unit in the polymer.

Example 8

In a half-liter bottle. Into a reflux condenser, thermometer, mechanical stirrer, and nitrogen inlet tube, 700 g (5.38 mol) of refined llaconic acid dissolved in 2800 cc of deionized water was added. The mechanical stirrer was started and the flask and its contents were heated with an oil bath while 700 g (9.71 moles) of acrylic acid was added. The reaction mixture was brought to 50 ° C ± 2 ° C over 1 hour while blowing nitrogen through it, after which the catalyst consisting of 20.4 g (0.0755 mol) of potassium persulfate was added all at once. A slow stream of nitrogen gas was then introduced into the system, and the reaction was followed in the usual manner by analyzing the bromine number. After 28 hours, 25 minutes, the conversion was 98% complete with regard to the copolymer formation, and after 31 hours, 10 minutes the increase was discontinued. The aqueous solution of the itaconic acid acrylic acid copolymer obtained in this way (weight ratio dei Reaklionsleilnchmer = -1: 1) showed the following characteristic physical properties: Brookfield viscosity with spindle no. 3, 30 rev / min. be 25 ° C - 3720 cps; specific gravity, 15/15 ° C = 1.146; n ² ^ '1% = 1.15; n ™ 0.33% - 1.81.

Example 9

The procedure of Example 2 was essentially repeated to prepare the solid copolymer of the prior Example (1.0 part by weight of llaconic acid zi 1.0 part by weight of acrylic acid) to partially carboxylate with the difference that 1.85 g of the mixed polymer and 18 ecm of water were used. After Ablau The decarboxylation was essentially complete in about 28 hours (39 ecm of the developed ci Carbon dioxide had been obtained). It was

: in partially decarboxylated solid copolymer product obtained whose absorption maximum in the UV range of the spectrum at a wavelength of 2.82 ηιμ at E!?. - 6.9 lay. The amount of developed Gas was 24 mole percent carbon dioxide per mole, valen / itaconic acid monomer unit in the poly meren.

Example 10

A solution of 6.35 g was partially decarboxylated solid polyitaconic acid in 40 ecm of water. The pH of this solution was 1.7. then an identical solution was prepared and with 1.5 ecm

10

Brought to 50 ° / ₀ aqueous potassium hydroxide to a pH value of 9.0. Both solutions then svurden V / ater filled up to 100 g (in each case to give a 5 ° / _o solution) and subjected to a series of tests with various aqueous Metaüsalzlösungen. The results thus obtained are summarized in the table below, where the numbers in ecm specify the amount of 2.5 ° / "aqueous metal salt solution, which is required ίο to the precipitation in 2 cc each of the two 5 ° / _o ii! to effect aqueous polymer solutions. A corresponding series of values / _0> ger aqueous polyitaconic was obtained with 5 ° is given for comparison purposes also.

Metal cation

Decarboxylated polymer pH value 1.7 pH value 9.0

l'olyitaconic acid pH value 1.0 pH value

Magnesium 0.10 0.25 no precipitate

Calcium 0.07 0.05 no precipitate

Barium 0.25 no precipitate 0.05

Iron (II) 0.05 0.05 no precipitate

Iron (Ul) 0.05 I 0.75 * no precipitate

Copper 0.05 I 0.10 * no precipitate

Zinc 0.20 * O.:o* no precipitate

·) ^R s a sudden precipitate was obtained at 0.05 ecm, but this was not permanent.

0.05

0.40 *

1.90 *

0.05

0.65 *

0.05

0.50 *

Example U

To a 2,000 cc four-necked round bottom flask, equipped with a reflux condenser, mechanical stirrer, nitrogen inlet tube, and thermometer, was placed 450 g (3.46 Mo!) Of refined itaconic acid in 1200 cc of deionized water. Stirring and the simultaneous introduction of nitrogen into the system was then started. The mixture was ^{heated to 60 °} C. after which complete dissolution occurred and 150 g (1.74 mol) methacrylic acid were added to the mixture. After equilibration, the final reaction mixture at 50 ⁰ C ± TC 7.1 g (0.026 mol) potassium persulfate was added with stirring to the heated system, which was then analyzed in the usual way at various time intervals by means of the bromine number. A 64% conversion had taken place after 24 hours. After adding a further 3.6 g (0.013 mol) of potassium persulfate to the mixture and heating it for a further 24 hours at 60 ° C. ± C, an 88.2% conversion had taken place. The solid itaconic acid-methacrylic acid mixed polymer obtained in this way with a weight ratio of the reactants of 3: 1 had the following characteristic viscosity properties after dilution to a 14% aqueous solution, based on the initial monomer weight: Brookfield viscosity, spindle No. 1, 30 rev / min. at 25 ° C = - 57 cP.

Example 12

The process described in Example 2 for polyitaconic acid is essentially used for partial decarboxylation of the solid copolymer obtained in the above example is repeated (3.0 parts by weight itaconic acid, 1.0 part by weight methacrylic acid). After completing this implementation, the corresponding Partially decarboxylated copolymers obtained.

Example 11

47.0 g (0.419 mol) of freshly crystallized itaconic anhydride (melting point: 64.5 to 67 ° C.) were added to a SOO ccm one-necked round bottom flask with a side arm, a reflux condenser, a thermometer and a drying tube, followed by dioxane and purified with 200 ecm 43.6 g (0.419 mol) of freshly distilled styrene were added. The flask and its contents were then placed in an oil bath at a constant temperature of 6O ⁰ C and occasionally shaken until the temperature of the reaction mixture reached 6O ⁰ C. (This took 20 minutes.) Then 1.02 g (0.00419 mol) of recrystallized benioyl peroxide was added to the mixture. The flask was then shaken every 5 minutes for 1 hour. After 1 hour, 4 minutes, the reaction mixture was removed from the bath and slowly poured into 1 liter of freshly dried benzene with magnetic stirring. Stirring was continued for four hours, then the precipitated solids were filtered through a Bucher funnel under a nitrogen atmosphere and quickly placed in a crystal dish in the vacuum desiccator. After drying for 40 hours in vacuo over P ₂ O _; the solid product weighed 20.7 g at room temperature. For the itaconic anhydride-styrene system with an equimolar weight ratio, this means a conversion of 22.8% to the polymer. By etwj 16stündiges drying of a small sample this: product in a Fisher-drying oven at 6O ⁰ C under reduced pressure, there was prepared a sample analysis forth.

Analysis (for 50 mole percent):

Calculated ... C 72.3, H 5.6;

Found ... C 69.87, H 5.33.

Based on the determined carbon and hydrogen, this corresponds to 55.8 mol percent Itacor acid anhydride.

Example 14

The procedure described in Example 2 was essentially repeated to produce the itaconic acid-slyrole copolymer of the above example to partially decarboxylate, with the difference that 2.16 g of the latter mixed polymer as starting material together with 15.6 ecm deionized water and

2.4 ecm 1.0309 n-potassium hydroxide solution is used became. After about 7 hours, the decarboxylation was essentially complete (24.5 ecm developed Carbon dioxide gases were recovered) and the product obtained was found to be partially decarboxylated solid copolymer. The amount of carbon dioxide gas evolved in this case was 9.9 mole percent carbon dioxide per mole equivalent of itaconic anhydride unit in this polymer.

Example 15

A solution of 6.35 g of partially decarboxylated solid polyitaconic acid in 40 ecm of water was prepared. The pH of this solution was with

1.5 ecm of 50% aqueous potassium hydroxide 9.0 set. Evaporation to dryness gave the potassium salt of the partially decarboxylated Polyitaconic acid.

In a similar manner, the corresponding sodium and ammonium salts of this acid were thereby obtained get that you simply the appropriate amount of sodium or Ammurüümhydrüxyd at steep of Potassium hydroxide was used in the above procedure.

Example 16

The Ver drive was essentially repeated to remove the partially decarboxylated monoethanolammonium salt to produce solid polyitaconic acid, using only the appropriate amounts of monoethanolamine used in place of ammonium hydroxide. After the completion of the implementation, the desired saw

ίο from the aqueous solution by evaporation of the same recovered to dryness under reduced pressure.

In a similar manner, other organic amine salts of this acid were obtained merely by using dat the corresponding amount of amine in place of de:

Monoethanolamine with otherwise the same reaction method used. Among the salts specially made in this way are those the partially decarboxylated polyitaconic acid mi diethanolamine, triethanolamine, ethylenediamine, di

ao ethylamine, triethylamine or with pyridine forms.

Example 17

The process described in Example 2 for the partial decarboxylation of polyitaconic acid was used

»5 essentially repeated, with the difference that no water was used as a solvent for the reaction. Instead, a film of the festet polymer was placed on a substrate and, as heated before standing, the reaction temperature was single Hch slightly higher than 100 ⁰ C. In any case, carbon dioxide gas is also evolved here, and solid, partially decarboxylated polyitaconic acid was also the product obtained.

Claims (6)

Patent claims: ! .Process for the partial decarboxylation of a polymeric carboxylic acid the (I) polyiaconic acid, (2) a copolymer of itaconic acid with a (Contains at least about 10 mole percent itaconic acid and his / u about 90 mole percent of an acidic Misdimonomeren with a polymerizable \ ./ f-Duplication in a carboxylic acid group or (J) a copolymer of itaconic acid with a content of at least 30 mole percent Itaconic acid and up to about 70 mol percent of a non-acidic mixed monomer with a polymerizable Double bond is. characterized, that the polymeric acid is heated in an aqueous medium at an elevated temperature until about 5 to 30 mole percent Evolved carbon dioxide per mole equivalent of aconic acid unit in the polymer. 2. Verfaliren according to claim 1, characterized in that an acidic aqueous medium is used 3. The method according to claim 1, characterized in that Then a basic aqueous medium is used, the basic medium as much a rabbit contains, dall the deearboxylierle product is only partially neutralized. 4. The method according to any one of the preceding claims, characterized in that the polymeric acid is heated to elwa M) up to 160 ° C. 5. The method according to any one of the preceding claims, characterized in that dall is used as a mixed monomer Acrylic acid, methacrylic acid or styrene is used. 6. The method according to any one of the preceding claims, characterized in that the product is converted into its salt by reaction with an alkali metal or alkaline earth metal.