FR2468628A1 - COMPOSITION FOR THE PREPARATION OF ACRYLAMIDE POLYMERS AND IMPROVED ACRYLIC ACIDS CONTAINING A 1,3 DIONE AND PROCESS FOR THE PREPARATION OF SUCH POLYMERS - Google Patents

Abstract

The present invention relates to a composition comprising a monomer chosen from acrylamide, acrylic acid, 2-acrylamido-2-, methylpropane sulfonic acid and its salts, and mixtures thereof, as well as a cyclic organic compound containing a 1,3-dione fragment corresponding to the formula

Description

The present invention relates to polymers

  water-soluble synthetics with high molecular weight

  as well as a process for their preparation, in particular

especially when the monomers contain an unacceptably high proportion of impurities resulting in the production of poor polymers having for example excessive proportions of insoluble products and / or unacceptably low and / or low viscosities

polymerization rates. More specifically, the in-

vention relates to the use of a cyclic compound

holding a fragment:

O O

There 1

-C-CH 2-C-

making it possible to obtain acrylamide polymers and / or

acrylic acid and / or 2-acrylamido-2-methyl-

  sulfonic propane and its salts which are essentially identical to polymers prepared from monomers

particularly pure.

  Acrylamide is conventionally prepared by hydrata-

  acrylonitrile, as well known in the art

than. Generally, this product is present in the reactor in the form of a concentrated solution (from 40 to% by weight). Acrylic acid is conventionally prepared

  by oxidation of propylene, as well known in the art

  fuck. In general, this product is accessible in the form of concentrated solutions, that is to say solutions having a concentration of 60% to solutions

  crystallizable. 2-acrylamido-2-methylpropane sul-

  fonique is conventionally prepared from acrylonitrile

and sulfuric acid by the Ritter reaction. This material

  riau is accessible in the form of a solid powder which must often have been purified by recrystallization. For economic reasons, it is essential that these

  products are directly polymerized into a hy-

soluble in high molecular weight. However, these so-

  monomeric lutions or powders appear to contain impurities

retained unknown at the rate of a few parts per million,

the exact quantity or type of which is still unknown

born to date. When the monomers are polymerized, even with this very low level of impurities, we often obtain

a completely unacceptable polymer.

  In solution polymerizations, attempts to solve these problems have involved one or more of the following conditions: (a) a temperature of

  very low drying; (b) thorough and on-purification

of the monomer solution: (c) a polymer time

very long rization; (d) the addition of very large proportions

  bearing urea monomer; and / or (e) polymerization in very dilute solutions. But each of these conditions

has been found unsatisfactory for industrial applications

trielles on a large scale because it requires a very high energy or because it is expensive in that the production speed of the polymers is very greatly reduced or that the percentage of polymer desired is

reduced to an unacceptable level.

In oil-in-water emulsion polymerizations

attempts to resolve these problems have im-

  plicated: (a) purifying the monomer; (b) polymer

  sation of very dilute solutions; (c) the use of ini-

different owners; (d) adding urea to the monomer; and

(e) the use of chain transfer agents. Any-

times, these conditions were also found to be unsatisfactory.

  health, for reasons identical or similar to those

set out above.

Therefore, the invention aims:

- to remedy this problem and allow the realization

  sation of a concentrated monomer solution without the need for

ter a thorough purification (that is to say a crystallization); to reduce to an industrially acceptable level (that is to say less than about 2% by weight) the content of insoluble products in the polymers of polyacrylamide and of polyacrylic acid polymerized in solution; to bring the standard viscosity of the polymers of polyacrylamide and of polyacrylic acid polymerized in emulsion to an acceptable level, that is to say higher, respectively, to 4.5 and 5.0 centipoise, approximately; to reduce the proportion of crosslinked polymer which forms during the polymerization and / or during the drying or grinding of a polymer of acrylamide, or of acrylic acid, or of 2-acrylamido-2methylpropane sulfonic acid ;

- improve the polymerization speed of mono-

  mothers of acrylic acid and 2-acrylamido-2- acid type

sulfonic methylpropane.

The subject of the present invention is a solution

acrylamide and / or acrylic acid and / or 2-acrylic acid-

  amido-2-methylpropane sulfonic monomer (s) comprising a cyclic organic compound containing a fragment corresponding to the formula: 0 o Il Il

-C-CH2-C-

  Preferably, the cyclic compound (hereinafter called 1,3-dione is present in a sufficient proportion so that, after polymerization of the monomer, an improved product is obtained, preferably a commercially acceptable product and / or

  the polymerization speed is increased. For polymers

  risations in solution, this generally means a te-

  neur in insoluble substances less than about 2%, in

weight. For emulsion polymerizations of homopolymer-

res of acrylamide or acrylic acid, this means a content of insoluble substances sufficiently low not to intentionally reduce the standard viscosity

  below about 4.5 centipoise. If we have the inten-

tion to obtain an emulsion polymerization product

  having a lower viscosity, we can use 1,3-

dione to increase the reaction speed.

When they are homopolymers of acrylic acid or 2acrylamido-2-methylpropane sulfonic acid and its

  salts, it means increasing the speed of poly-

  merit. The invention also relates to a process for the preparation of a high water-soluble polymer of polyacrylamide or polyacrylic acid in which the content of insoluble substances is reduced to a proportion of less than approximately 2%, according to which a type monomer is polymerized.

  acrylamide or acrylic acid in aqueous solution,

together with other ethylenically unsaturated monomers

nique, and the resulting polymer is dried, drying with

less being performed in the presence of a 1,3-dione.

  The invention also relates to a process for pre-

  paration of a high water-soluble polymer, consisting in polymerizing in emulsion a monomer of acrylamide type, or

acrylic acid or 2-acrylamido-2-methylpropane sul-

  fonique, possibly with other unsaturated monomers

  ethylenic ration, in the presence of a 1,3-dione.

The invention also relates to a method for improving the

polymerization rate of 2-acryl- acid homopolymers

amido-2-methylpropane sulfonic and its salts, consisting

  to carry out the polymerization in the presence of a 1,3-dione.

  Other aims, advantages and characteristics of the

vention will appear in the description which follows.

  The compounds which can be used according to the invention for

get improved polymers are organic compounds

cyclic ques containing a fragment corresponding to the formula

the:

0 0

if he

-C-CH2-C-

These compounds are

in the compound.

As nonlimiting examples of these 1,3-diones, there may be mentioned substituted and unsubstituted derivatives of 1,3-cyclo

pentanedione, of 1,3-cyclohexanedione, of 1,3-cyclohepta-

  nedione, of 1,3-cyclooctanedione; 1,3-cyclodecanedione;

5,5-dimethyl-1,3-cyclohexanedione; of 5,5-diethyl-1,3-

cyclohexanedione; 1,3,5-cyclohexanetrione and its tautomer phloroglucinol (1,3,5-trihydroxybenzene); tetrahydronaphthalene-1,3dione; barbituric acid; and

other compounds of this type.

  The tautomers of these compounds, containing the group -C-CH = C- fall within the definition of 1,3-dione such as O OH as used in the present invention,

just like metallic enolates including carbal-

  coxy dimedone metal enolates such as carbomethoxy dimedone enolate sodium, carbethoxy dimedone enolate

potassium, etc.

It is very preferable that 1,3-dione is 5,5-

dimethyl-1,3-cyclohexanedione, also called methone or dimedone. When 1,3-dione is added to the monomer and the monomer is then polymerized, 1,3-dione should not also be a polymerization inhibitor. If it is an inhibitor, the dione, as well as all that it

eliminates, must be removed from the monomer before the poly-

  merit. One way to do this is

  consists in passing the solution of monomer (s) over a

  activated carbon bed. When it is a polymerization

  tion in solution, 1,3-dione can also be added

with polymer gel, before drying.

  When 1,3-dione is not stable under con-

polymerization editions used, the polymerization conditions should be changed to avoid destabilization, or 1,3-dione should be added to the gel

polymer before drying.

  In some of the cases described below, it has been discovered that it is desirable to include with 1,3-dione up to about 20% by weight (based on the monomer content) of urea or a urea derivative. It is better to use

  urea itself, in a proportion of 5 to 10%. Compo-

  These suitable types are described in the U.S. Patent. n 3.622. 533. Urea can be added before, after

or at the same time as 1,3-dione.

The monomers to be polymerized according to the invention are acrylamide, acrylic acid, as well as 2-acryl acid

2468 628

  amido-2-methylpropane sulfonic and its salts. It is also possible to prepare copolymers of the mentioned monomers, or of one or more of the mentioned monomers with other

  ethylenically unsaturated monomers suitable for pre-

  paration of water-soluble products. As examples no

  limiting of these other monomers, mention will be made of: metha-

crylamide, acrylic acid salts, methacryl-

  lique and its salts, methyl acrylate, acrylate

  ethyl, propyl acrylate, methacrylate

  thyle, ethyl methacrylate, dimethyl acrylate-

  aminoethyl, dimethylaminoethyl methacrylate,

  hydroxyethyl acrylate, hydroxy methacrylate

ethyl, methyl sulfate acrylate or diethylamino methacrylate

  - ethyl, styrene, acrylonitrile, 3- chloride

  (methylacrylamido) propyl-tri-methylammonium, vinyl methyl ether, vinyl ethyl ether, alkali metal or ammonium salts of vinyl sulfonic acid, etc. All or part of the acrylamide portion of

polymers can be hydrolyzed.

  The polymerization method to be used according to the invention

  tion is any mode conventionally used to polymerize

  these monomers. These are particularly polymerized

  tions in solution and in emulsion, although other modes of polymerization may be used, for example pearl polymerizations, or of the dispersion suspension type. The particular polymerization system for

  each of these operating modes is the one that is classi-

  only used. When it is a polymerization in

solution, this generally implies the use of

  tion of one or more azo initiators, with or without

a redox system, and possibly additives classi-

  such as sequestering agents, alcohols and diluents

if necessary for the polymerization. When

  this is an emulsion polymerization, which is an emulsion

water-in-oil, this involves the use of a water-in-oil emulsifying agent, an oily phase such as toluene, xylene, or a paraffinic oil, and s 7

a free radical initiator.

  As the present invention does not depend on the mode of polymerization used, all necessary explanations can be found in the literature. In addition, the proportions and the nature of each of the constituents vary depending on

before the polymerized monomers and the operating conditions

res in which the polymerization must be carried out.

  It has been found that the proportion of 1,3-dione used

  Reading according to the present invention depends, at least in part, on the type of polymerization, on the type of purification of the monomer, on the degree of aging of the monomer / 1,3-dione composition, for the polymerizations in solution of the temperature at which the product is produced and / or dried, the presence or absence of urea and its proportion, the proportion of impurities in the concentrated monomer solution, as well as the residence time of the polymer at the maximum temperature. As such we cannot define an exact "polymer improvement ratio". Generally, however, it represents approximately 0.001

  at 2% (or more) of the weight of the monomer and, more particularly-

  the higher proportions being used

in the case of emulsion polymerizations and the proportions

  lowest values being used in the case of poly-

  merits in solution. For emulsion polymerizations

  sion, the preferable proportion for solutions that are not aged or aged at room temperature is approximately

0.3 to 1.0% and more preferably about 0.4 to 0.7% by weight. When-

  that accelerated aging is used (at more than about 50C for more than about 2 hours), the preferable proportion is about 0.005 to 0.2% and, better still, about 0.007 to 0.1%. For solution polymerizations, the preferred proportion is approximately 0.03 to 0.4% and, better still,

from about 0.05 to 0.25% by weight.

For polymerizations in acrylamide solution and

  of acrylic acid, it has been found to be advantageous: (a) of puri

pride the concentrated monomer solution by bringing it into contact with a cation exchange resin and / or activated carbon - it is unclear what is removed by

  these operations, but we noticed that we got better

  their results; (b) in addition to use urea when the drying temperature is higher than approximately 80 ° C., in particular higher than 850 ° C., and very particularly 90 ° C. or more; and (c) using the monomer solution /

  1,3-dione as soon as possible, i.e. without aging-

  prolonged. In addition, it is also possible to carry out the

advantages of the present invention by adding the 1,3-

  dione, not to the monomer, but rather to the polymer gel

  sultant, before drying it. This is not as desirable, as great difficulty may be experienced in uniformly incorporating the 1,3-dione in the gel by mixing. This shows that, regardless of how the 1,3-dione works, it seems to act during

  the drying stage of a solution polymerization.

  For emulsion polymerizations, it has proved advantageous: (a) to age the monomer / 1,3-dione composition for approximately 5 days before its use,

or (b) aging the composition at high temperature.

  vee for a few hours (60 to 80 ° C for about 5 hours) before use. This aging has been shown to improve the effectiveness of 1,3-dione. However, one obtains beneficial effects without aging, by using higher proportions of 1,3dione,

for example from about 0.9 to 2% relative to the monomer.

To prepare the acrylamide or acrylic acid / 1,3-dione solutions according to the present invention, it has proved advantageous to dissolve the 1,3-dione in the concentrated monomer solution before any dilution for the purpose of polymerization. . This is due to the long period of time

  found to be necessary to dissolve 1,3-dione in a so-

diluted lution, although essentially no one has noticed

no difference in performance. To prepare the solutions

  2-acrylamido-2-methylpropane sulfonic acid / 1,3-

  dione, you can just mix the two with water.

  It is also possible to incorporate 1,3-dione in the aczy-

  lonitrile or propylene from which the polymers are prepared.

The following nonlimiting examples are given uni-

  as an illustration of the present invention.

  Unless otherwise indicated, the parts and percentages are

expressed by weight.

Example 1

  Preparation of acrvlamide / 1,3-dione solutions

  (a) In a container lined with polyethylene

lene, preferably the one in which will take place later-

  polymerization If it is a solution polymerization, 810.9 g of an aqueous acrylamide solution at 51.3% "such as" and 0.83 g of methone are introduced. We

  stir this mass in air, using a magnetic stirrer

tick, for about 5 minutes to dissolve the mete

thone. It contains 0.2% methone, compared to

acrylamide monomer.

(b) The operation described in (a) is repeated but, before introduction of the methone, the aqueous acrylamide solution is passed over a bed of R-exchange resin

  cations (AmberliteR IR-120, supplied by Rohm and Haas).

  (c) We operate as described in (a) but, before intro

  duction of methone, the aqueous acrylamide solution is passed (1) over a bed of cation exchange resin (AmberliteR IR-120) then (2) over a bed of activated carbon (Nuchar WV-L of 2.38 0.55 mm)

  (d) We prepare other similar solutions, making

can vary the proportions of methone, as indicated in

the examples below.

Example 2

Polymerization in solution of the monomer of example l (c) The solution of monomer of example l (c) is subjected

to a solution polymerization, as follows: It is introduced

  added to a polyethylene reactor of about 4 liters and subjected to magnetic stirring. Then we add

  the following ingredients, while continuing to stir

tion: Deionized water 2311.2 g 2% ethylene diaminetetracetic acid aqueous solution 4.2 ml 2% aqueous isopropanol solution 3.2 ml Anhydrous sodium sulfate 16.6 g Anhydrous ammonium sulfate 4.2 g Urea 20.8 g When the whole is dissolved, the pH of the reaction mass is brought to 3.0 using sulfuric acid. A nitrogen purge is started at the rate of approximately 1000 ml / hour for 30 minutes, while bringing the reaction mass to approximately 35 ° C. While continuing the nitrogen purge, the polymerization begins within a few minutes of the introduction of the catalysts:

13.3 ml of 2,2'-azobis (2,4-dimethyl-4-methoxy-

valeronitrile) at 0.0078 g / ml and, 6 ml of 2,2'-azobis (cyanovaleric) acid at

0.02 g / ml.

The polymerization is allowed to continue practically-

adiabatically by isolating the reactor. The polymerization product is allowed to undergo an exotherm of 29.8 ° C. in about 2 hours, before being transferred to a hardening oven at around 70 ° C. in which it is made to cure for a further 18 hours, thus obtaining 3200 g of

a rigid gelled product.

The gel is then cut into thin slices which

dries portions in a convection oven until

7-10% volatile substances

  dual at temperatures of respectively 90, 100, and 113 + 2 C. The dried product is reduced to particles in a Waring mixer, it is passed through a sieve in order to obtain a

product passing through the 0.84 mm sieve.

Example 3

Evaluation of the product of Example 2 The product prepared in Example 2 is evaluated as follows:

  0.3 g of the dried product is dissolved at each of the temperatures.

peratures indicated in deionized water, in order to obtain

  provide 300 g of an aqueous 0.1% polymer solution. The solution is passed through a weighed sieve

0.149 mm opening, in order to eliminate the insoluble material by wire-

tration. The sieve is washed with about 500 ml of water

deionized at room temperature and dried at 1000C for

  overnight before determining the amount of insoluble

  reported as a percentage of insoluble substances.

  The percentage of residual volatiles is determined by measuring the weight loss of a sample

  1 g after drying at 100-1100C for 2 hours.

  The degree of hydrolysis (carboxyl%) is determined by conductometric titration of the carboxyl content of the polymer. The resulting product is all the better for

point of view of non-ionic compounds that the number

carried is lower.

  The viscosity "as is" is determined by dissolving 0.3 g of product in deionized water for 2 hours,

  in order to obtain 300 g of aqueous solution, the filter is filtered.

  soluble using a 0.149 mm mesh screen

  then add enough sodium chloride

  to obtain a 1 molar NaCl solution and one determines

  does its Brookfield viscosity using a UL adapter.

  The result indicates the performance of the resulting product, the final product being all the better as the number

*is higher.

The results obtained, as well as comparative results

ratives obtained on a sample prepared according to the same

  operating mode but without using a methone, are indicated

listed in Table I below.

  It follows from the results obtained that the addition of 0.2% methone strongly increases the viscosity "such as" and that the percentage of insoluble substances

  decreases in value from around 60% to less than 0.4%.

TABLE I

Results of Example 2 and the Comparative Test

  Example 2, temperature Compara- test

drying tif, temperature-

 C 100 C 113 2 Drying re

90 C 100 C

  Viscosity "such as" 3.3 3.3 3.3 1.4 1.4

Substances vo-

latile% 7.72 7.03 7.96 7.72 9.10

Substances

soluble% 0.03 0.07 0.40 60.0 62.4

Carboxyl% 0.075 0.038 0.19 - -

Example 4

  We operate as in examples 2 and 3, but reducing

  the proportion of methone at 0.10% and 0.05% respectively.

  The following results are obtained: OC drying temperature

100

  0.10% methone Viscosity "such as" 3.3 3.3 Volatile substances,% 8, 25 7.08 Insoluble substances,% 0.9 0.7 Carboxylate,% - 0.15 0.05% of methone Viscosity "such as" 3.3 3.1 Volatile substances,% 8.21 6.67 Insoluble substances,% 1.6 13.1 Carboxyl,% 0.15 0.075 The results obtained demonstrate that when we reduce

the quantity of methone, the percentage of substances insoluble

lubles believes. They also demonstrate that when the pro-

portion of methone is 0.05% and the drying temperature

  chage is 100 C, the proportion of methone is insufficient

health to bring the content of insoluble substances to

below 2%.

  EXAMPLES 5 TO 10 The procedure is as in Examples 2 and 3, but varying (1) the mode of purification and (2) the proportion of methone. The results obtained are reported in Table II below. It follows from the table that when we increase

the proportion of methone, the resulting product is improved

re (as evidenced by the increase in the screw-

cosity "such as" and the reduction in the percentage of

insoluble substances).

Examples 11 to 20 The basic procedure of Examples 2 and 3 is used, but varying the treatment of the monomer, the presence and the proportion of urea and methone, the catalytic system and the pH, the percentage of solid substances.

the maximum temperature, as well as the temperature time

  maximum size, as detailed in the table

Illa below. Regarding the treatment of mono-

  mother, "YES" means that it is treated with a cation exchange resin as in example lb, and "NONE" means that it is prepared as in example la. In Example 2, the percentage of (NH4) 2SO4 is 1%, the percentage of Na2SO4 is 4%, and the percentage of urea

is 5% O.

  The characteristics of the dry product are indicated in

table IIIb.

In order to show that the 1,3-dione and / or urea may not be added to the monomer and be added to the gel, thus being only present during the drying stage, several subsequent additions are made, such as follows: Example 15: subsequent addition of 0.1% methone and 10% urea

  Example 16: subsequent addition of 0.1% methone only-

is lying

Examples 19 and 20: subsequent addition of only 10% urea

lement.

The characteristics of these dry products are also

shown in Table IIIb.

  It follows from Tables IIIa and IIIb that the effect of methone is independent of the catalytic system or

  polymerization conditions and that it is beneficial to use

  read a combination of methone and urea.

TABLE II

Example Treatment of the monomer Results of Examples 5 to 10 Characteristics of the product dried at 90/100 Methone% Viscosity "such as" Insol.% Vol.% Carboxyl% 0.05 0O 20 0.26 0.49 0.26

1.5 / 1.3

2.4 / 2.1

3.3 / 3.3

3.3 / 3.3

3.3 / 3.1

3.3 / 3.2

53.5 / 59.1

18.1 / 29.1

1.7 / 0.8

0.9 / 0.7

0.13 / 1.9

1.2 / 3.3

8.30 / 8.10 - / -

7.57 / 6.62 - / -

7.68 / 8.35 - / 0.075

7.24 / 6.7 0.15 / 0.075

6.27 / 5.92 0.75 / 0.38

11.2 / 6.95 0/0

(i) cation exchange resin only, as in example lb (ii) cation exchange resin only, aged 2-3 days at room temperature before use (iii) cation exchange resin, activated carbon; monomer diluted to 13% before

addition of methone.

Pa N 0% oN i i i ii ii iii

TABLE IIIa

  Treatment Example low yes yes yes yes None None yes yes yes yes% t M6thone Urge O02 0.2 0r05 op05 Oil 0.1 0.1 0.1 s0, 0 t0, 0, 0%% Catalyst (NH14) 2S04 Na2SO4 pH 1.0 1.0 1.0 3.0 3.0 3tO 3e0 3i 9.0 4.0 4lO, 0 AAAABBBB Solids% 11t3 11s3 11t3 1113, 11y3 Tmax. C Time at T, max Catalyst / pH-A identical to Ex. 2; B es' propane), pH 4.5 O 0.1% pipadridine added initially

t 2,2'-azobis (2-amidino-) hydrochloride

uI NI c "co ru co

TABLE IIIb

Dry product characteristics No post-Visc Additions. "Such naked" Insol% Vol%

1.5 / 1.5

3.3 / 3.3

1.7 / 2.2

3.4 / 3.2

1.2 / 1.2

3.0 / 2.1

3.5 / 3.2

3.6 / 3.3

1.8 / - 2.4 / -

.3 / 49.2

1.7 / 0.8

39.7 / 23.5

0.8 / 4.5

, 7 / 63.6

11.9 / 34.3

1.4 / 11.0

0.8 / 5.5

48.9 / -

, 1 / -

8.21 / 7.65

7.68 / 8.35

6.83 / 7.55

8.63 / 7.86

12.6 / 9.8

, 5 / 9.1

9.0 / 8.5

8.2 / 6.7 9.4 / - 8.8 / - after drying at 90/100 C Post-Additions to Visc Gel. "such

Insol% Vol%

3.2 / 3.4

3.6 / 3.2

0.13 / 8.5

4.3 / 4.2

3.6 / - 3.7 / -

0.57 / -

1.0 / -

9.62 / 4.43

8.02 / 5.21

m 9.7 / - 7.1 / - ro 0% - Ce Co

Example

Examples 21 to 28 The basic procedure of Examples 2 and 3 is used, but using: a different untreated monomer,

27% solids, diethylenetriaminepen-

tacetic as sequestering agent, 2,2'-azobis hydrochloride (2amidinopropane) as catalyst with a redox system ammonium persulfate / ferrous ammonium sulfate, pH 6.0, initiation of the reaction at 0 C, and one

4 hour residence time.

  The proportions of methone and urea used, as well as the characteristics of the dry product for the dried product at around 60 to 70 C up to a content of substances

volatiles of approximately 12% are indicated in Table IV below.

below.

It follows from the results obtained that, under these conditions

polymerization, methone only provides pro-

  acceptable product (viscosity "as" high and content of insoluble substances less than about 2%) while

this is not the case with urea alone.

TABLE IV

  Results of Examples 21 to 28 Characteristics of the Dry Product Viscosity Percentage of Ex. Methone% Urea% "such as" insoluble substances

21 - - 3.9 7.3

22 0.01 - 4.4 1.8

23 0.05 - 4.6 1.3

24 0.1 - 4.6 0.6

- - 3.8 8.2

26 - 1.0 3.1 7.0

27 - 2.5 4.3 6.1

28 - 5.0 4.1 6.7

EXAMPLES 29 to 38 Emulsion polymerization of acrylamide Methone is added to aqueous solutions of acrylamide, as in example la, with stirring for approximately 5 minutes. The following procedure is used, but adding sodium hydroxide when the pH

is 9.

In a suitable reactor is introduced 2100.0 per-

  acrylamide, in the form of a 50.47% aqueous solution and 850.0 parts of deionized water. This solution of 2.12 parts of disodium salt of ethylenediamine tetracetic acid and 1.15 parts of hydrous ferric sulfate is added (72% Fe2 (SO4) 3 is used at a rate of 4.5 parts / 1000 parts of H20). The pH of the resulting solution is brought to 5.0. This constitutes the aqueous phase

of monomer.

The oily phase is prepared by dissolving 90.0 per-

  sorbitan monooleate ties in 1040.0 parts of

  AMSCO OMS, clear oily liquid accessible in the com-

  merce, supplied by Union Oil Co. of Califormie, E.U.A.

  In a suitable high-speed homogenizer,

  introduces the total system in the oil phase. We put the ap-

  similar in operation and the aqueous phase is slowly introduced

  se of monomer, thus obtaining an emulsion having a vis-

cosity of 990 cps. The dispersed phase of the emulsion results

aunt has particle sizes of about 2.5 microns

or less.

  The whole emulsion system is introduced into a suitable reactor, with stirring. 70.0 parts per million (based on the monomer) of t-butyl hydroperoxide are added. The resulting medium is purged with nitrogen gas in order to expel oxygen from the system. Stirring is continued and sodium metabisulfite is slowly pumped into the reactor over 6 hours while keeping the reactor at

   C approximately, at the end of which approximately 100 ppm (compared to

port to monomer) have been added. The viscous emulsion

resulting has a 99.49% conversion of acryl-

amide. The polymer emulsion is stabilized by adding 78.28 parts of an aqueous solution of sodium metabisulfite

at 30%. The emulsion is maintained under po-

lymerization (60 minutes at 40 C) in order to practically

fully react the remaining acrylamide. The emulsion

contains 0.4% bisulfite which is used to stabilize the system

polymeric teme.

  5.5% of a 70% solution of bis (2-ethylhexyl) sulfosuccinate is added to the resulting polymer emulsion as a mixture of inverting agents. sodium in AMSCO OMS and 2.0% of the reaction product of one mole of octyl phenol and 7.5

moles of ethylene oxide. The resulting emulsion is maintained

  aunt at 40 C for another hour at the end of which the product is aesthetic and free of particles. The dispersed polymer phase has particle sizes of 2.5 microns or less. The standard viscosity is as indicated in Table V. The standard viscosity of the resulting product, as well as

  those of other products obtained by varying the amount

methone and the degree of aging, are indi-

listed in Table V below.

TABLE V

  Results obtained using methone in an emulsion polymerization Results of examples 29 to 38 Ex. Methone% Aging pH Standard viscosity (days)

29 - - 5 3.5

30 0.5 - 5 3.9

31 0.75 - 5 4.2

32 1.0 - 5 4.7

33 1.5 - 5 4.5

34 0.2 5 9 4.0

35 0.5 5 9 5.0

36 0.2 7 5 4.3

37 0.5 7 5 4.9

38 0.1 d 5 4.95

e accelerated aging at 60-80 C for 5 hours.

Examples 39 to 42 Preparation of Copolymers The basic procedure of Example 2 is used, but replacing 10% by weight of the acrylamide with an equivalent weight of each of the following monomers: (a) Acrylic acid (b) 2- Ammonium acrylyl-2-methylpropanesulfonate (c) dimethylaminoethyl methacrylate methyl sulfate For (a) and (b) the pH is adjusted using sodium hydroxide. Comparable improved results are obtained compared to those obtained with the same methone-free copolymers.

Example 43

  Preparation of a 95/5 copolymer of acrylic acid / acrylic-

amide 214 g of crystallizable acrylic acid (Rohm-and Haas, "Production" quality) are introduced into a stainless steel beaker. While stirring using a magnetic stirrer, 29% ammonia is added (technique) and the temperature is maintained at a value less than or equal to 35 C up to pH 7.5 (approximately 1, 5 o'clock). We add

  distilled water to bring the total weight to 428 g.

  The solution is transferred to a 1 liter glass beaker.

and, while stirring, 1.07 g of methone (0.5% relative to acrylic acid) are added. It dissolves in approximately 10 minutes. 23 g of acrylamide are then added to

  % and we operate as in examples 29 to 38 in order to

  putting the monomers to an emulsion polymerization.

The standard viscosity is 5.7 centipoise.

When operating as above, but without methone,

  the standard viscosity is less than 2.9 centipoise.

Example 44

  Preparation of a homopolymer of acrylic acid

  The procedure is as described in Example 43, in order to homopo-

  lymerize acrylic acid. The product obtained has a

standard viscosity of 5.2 cps.

  When you don't add methone, the viscosity

standard is -2.5 cps.

Examples 45 to 50

  The procedure is as described in Example 2, but replacing

  ering methone by the additives indicated in Table VI below, in the proportions indicated. The results of drying the polyacrylamide at 90 ° C. are also reported in the table. It follows from the table that the sodium enolate of carbethoxy dimedone, which can be an intermediate product in the preparation of methone, provides the best results, in comparison with all

additives tested.

Ex. Witness additive None

1,3-Cyclohexane-

dione 46 Phloroglucinol

47 Barbitic acid

  rique 48 Sodium enolate of 49 carbethoxy dimedone OC2H5

501/25

O = / - Na CH 3 CF.

TABLE VI

Quantity Dry product added Viscosity% "as"

____ 1.3

0.12 3.3

0.17 2.4

  0.14 0.167 0.25 0.167 3.0 3.5 3.5 3.6 (drying at 90 ° C)

Flight. Insol.

%%

8.8 57.5

7.8 6.5

9.1 29.7

, 8 8.4 8.8, 3 14.1 3.1 0.07 0.03

Example 51

1,3-Indanedione

  The procedure is as described in Example 2, but replacing

  erasing methone by 0.05% by weight of 1,3-indanedione: O The monomer does not polymerize, because indanedione serves

polymerization inhibitor.

  The procedure is as described in Example 15, in order to effect

kill a post-addition (subsequent addition) of 1,3-indane

  dione (0.2%) and urea (5.0%). This is how the polymer

  re, prepared without additives, is dried in the presence of additives

  tifs. The results obtained by drying at 90 ° C. are as follows: Viscosity "such as" 2.9 volatile substances,% 7.4 insoluble substances,% 0.13 This is how the content of insoluble substances is

less than 2%, approximately.

Example 52

  Meldrum acid The procedure is as described in Example 2, but by varying the pH and replacing the methone with Meldrum acid:

CH3 O

  X CH KO C3 o Two polymerizations are carried out: one at pH 4.5 and

  the other at pH 8.0. It follows from the results indicated below

* below we get a better product at the most pH

Student. It follows that 1,3-dione, if present

te during polymerization, not just as post-

additive, must be stable under polymer conditions

to be effective.

  The products dried at 90 ° C. give the following results: pH 4.5 pH 8.0 Viscosity "such as" 1.4 2.1 Volatile substances,% 9.9 9.2 Insoluble substances,% 60.0 38.5 Examples 53 to 64 Using the basic procedure of Example 2, the copolymers and homopolymers identified are prepared.

in Table VII. We are also preparing witnesses without

thone.

  In Table VII: AMD = acrylamide; AMPS = acid 2-

  sulfonic acrylamido-2-methylpropane; AN = acrylonitrile; and MAPTAC = 3- (methylacrylamido) propyltriethyl ammonium chloride. IWNF means that the product cannot be filtered and the percentage of substance cannot be determined

these insoluble.

  In Examples 57 and 58, 5% urea is used and

  operates at a solid content of 10.3%. We are-

  carry out Examples 59 to 62 in the absence of urea and at a

  solid content of 13%. We prepare the examples

ples 63 and 64 in the absence of urea and a redox system, but using sodium hydroxide to

adjust the pH.

  For examples 63 and 64 at 100% AMPS, the speed-

  its polymerization means expressed in degrees centi-

  exothermic grade / minute adiabatically are determined as follows: Example Methone Speed

63 NO 0.07 C / grain.

64 YES 0.14 C / min.

  This is how using methone doubles the speed

polymerization.

Examples 53 to 62 show the effect of using methone to reduce the proportion of

insoluble substances.

Example 65

  The procedure is as described in Example 1 (a) to prepare an acrylamide solution containing 0.2% methone. The solution is left to stand for one night and then passed over an activated carbon bed (Nuchar WV-L from

2.28 to 0.55 mm).

The resulting monomer, not containing methone, is polymerized as described in Example 2 above. The polymer product is dried at 90 C. Its viscosity "such that"

  is greater than 2.8 and it contains less than 2% of subs-

insoluble tances.

TABLE VII

  Results of Examples 53 to 64 Monomer of (Moles%) Weight% of Methone Characteristics of the product dried at 90 C / 100 C Visc. "Such as" Volatiles% Insoluble%

1-YEAR, 99-AMD

1-YEAR, 99-AMD

-MAPTAC, 90-AMD

-MAPTAC, 90-AMD

-AMPS, 95-AMD

-AMPS, 95-AMD

-AMPS, 95-AMD

-AMPS, 95-AMD

-AMPS, 90-AMD

-AMPS, 90-AMD

AMPS AMPS ---- 0.1 0.15 0.1 0.1 _---- 0.1 0.1 0.1

1.3 / 1.2 8J9 / 81

31 4 / 2.9 81 8/7, 9

2.9 / - 7.7 / -

2.7 / - 9, 1 / -

3.2 / 3.0 9.5 / 8.4

3.0 / 3.0 9.5 / 810

3.0 / 3.0 8.4 / 9; 6

3.3 / 3.3 8.7 / 8.1

NO REACTION

2.9 / 2.9 9.6 / 8.5

- / 1, 3 - / 6.3

- / 1, 4 - / 8.9

59 y 3/62, 9

7 3 / 13.0

7, 7 / -

0.13 / -

0.7 / 12; 1

None / None

WNF / WNF

None / 0, 2 None / None

- / 0., 63

- / 0, 10

or oo Co

Example

Claims (24)

1. Composition comprising a monomer chosen from   acrylamide, acrylic acid, 2-acrylamido-2- acid   sulfonic methylpropane and its salts, and mixtures thereof, as well as a cyclic organic compound containing a frag- 1,3-dione corresponding to the formula: O O I! he -C-CH2-C-   2. Composition according to claim 1, character-   sée in that the 1,3-dione is present in a proportion improving the product obtained by the polymerization of the monomer. 3. Composition according to claim 1, character- that the 1,3-dione is present in a proportion representing about 0.001 to 2% of the weight of the monomer. 4. Composition according to claim 1, character-   in that it additionally contains at least one monomer additional, ethylenically unsaturated, copolymerized   ble with it giving a water-soluble copolymer. 5. The polymerized composition of claim 1, wherein the 1,3-dione is not a polymerization inhibitor.   6. Composition according to any one of the claims previous cations, characterized in that the 1,3-dione is 5,5dimethyl-1,3-cyclohexanedione or its tautomer 5,5-dimethyl-tetrahydro-m-resorcinol.   7. Composition according to any one of the claims   cations 1 to 5, characterized in that 1,3-dione is essentially chosen from 1,3-cyclohexane dione, phloroglucinol, barbituric acid, carbomethoxy dimedone enolate sodium and carbethoxy dimedone enolate potassium.   8. Process for preparing a high hydro polymer   soluble according to which a selected monomer is polymerized   among acrylamide, acrylic acid, 2-acryl-   sulfonic amidopropane and its salts, and mixtures thereof, characterized in that the monomer, before polymerization, is added to a cyclic organic compound which is not a polymerization inhibitor and which contains a 1,3-dione fragment corresponding to the formula: 0 0 He he -C-CH2-C-   9. Method according to claim 8, characterized in that the monomer is an aqueous solution containing from about 40 to 60% by weight of acrylamide monomer when 13 is added 1,3-dione. 10. Method according to claim 9, characterized in that the acrylamide solution is diluted to a   concentration of approximately 10 to 35% by weight of acrylamide before polymerization. 11. Process according to any one of the claims.   tions 8 to 10, characterized in that the polymerization is solution polymerization. 12. Method according to claim 11, characterized in that the 1,3dione is present in a proportion   representing approximately 0.03 to 0.4% of the weight of the monomer. 13. Method according to claim 11, characterized in that the product is dried after polymerization. 14. The method of claim 13, characterized in that the monomer is acrylamide and the drying is carried out at a temperature above about 80 C and urea is also added to the acrylamide before polymerization. 15. The method of claim 8, characterized in that the polymerization is a polymerization in water-in-oil emulsion. 16. Method according to claim 15, characterized in that the 1,3dione is present in a proportion representing about 0.3 to 1% of the weight of the monomer. 17. Method according to claim 15, characterized   in that 1,3-dione is used in a proportion represented   feeling about 0.005 to 0.2% of the weight of the monomer and the mixture is aged at a temperature above C approximately, for more than approximately 2 hours.   18. Process for preparing a high hydro polymer soluble consisting in polymerizing a monomer chosen from acrylamide, acrylic acid, 2-acrylamido-2-methylpropane sulfonic acid and its salts, and their mixtures, and in drying the resulting polymer, characterized in that one adds the polymer, after polymerization and before drying, of a cyclic organic compound containing a 1,3-dione fragment corresponding to the formula: 0 0 He II -C-CH2-C-   19. Process according to any one of the claims. tions 8 to 18, characterized in that 1,3-dione is pre-   feels in a proportion representing about 0.001 to 2% the weight of the monomer. 20. Process according to any one of the claims.   tions 8 to 19, characterized in that the 1,3-dione is 5,5-dimethyl-1,3cyclohexanedione or its tautomer, le, 5-dimethyl-tetrahydro-m-resorcinol.   21. Process according to any one of the claims   tions 8 to 19, characterized in that 1,3-dione is es-   selected from 1,3-cyclohexanedione, phloroglucinol, barbituric acid, carbomethoxy dimedone   sodium enolate and carbethoxy dimedone potassium enolate. 22. Process according to any one of the claims   tions 8 to 21, characterized in that it is copolymerized with   minus one additional ethylenically unsaturated monomer nique, with the monomer, in order to obtain a hydro- soluble.   23. Process according to any one of the claims tions 8 to 22, characterized in that urea is added monomer before polymerization.   24.A process according to any one of the claims tions 8 to 22, characterized in that urea is added after polymerization and before drying.