FI67870B - PULVERFORMED STARKA CATIONIC POLYELEKTROLYTET PAO BASEN AV ACRYLAMID OCH DIMETHYLAMINOETHYLACRYLATE I FORM AV ETT KVATERNAERT AMMONIUMSALT ELLER ETT SYRAADDITIONSSALT SAMT POLYELEKTROLYTERNAS SENS - Google Patents

Description

1 67870

Powdered strong cationic polyelectrolytes based on acrylamide and dimethylaminoethyl acrylate in the form of a quaternary ammonium salt or an acid addition salt and the use of polyelectrolytes for suspending solids and emulsifying liquids

The present invention relates to powdered strong cationic polyelectrolytes based on dimethylaminoethyl acrylate in the form of ac-10yl amide and a quaternary ammonium salt or acid addition salt, and to the use of polyelectrolytes for suspending solids and emulsifying liquids.

15 For some years, cationic polyelectrolytes have been used in pollution control to remove water from sewage sludge.

Of these, copolymers of acrylamide and cationic monomers having a high molecular weight of 20 are considered to be very good. FR Patent Application No. 2,390,983 discloses powdered water-soluble cationic polyelectrolytes based on acrylamide and a dimethyl aminoethyl acrylate in the form of a quaternary ketone chain and quaternary copolymer of the quaternary ammonium salt or acid addition salt and containing from 10 to 50 molar liposomes. having at the same time a specific viscosity of more than 6 measured at a temperature of 90 ° C in molar sodium chloride solution and a calculated cation number of more than 90% of the theoretical cation number, and the use of these polyelectrolytes for suspending community sludges.

But when emulsifying liquids and / or flocculating suspensions which are highly colloidal and hydro-35 in shape and rich in volatiles and / or have a high zeta potential, Z, such as organic, mineral, biological, stabilized or digested sludges, such polyelectrolytes are not efficient enough.

It has now been found that powdered strong water-soluble cationic polyelectrolytes consisting of copolymers of acrylamide and dimethylaminoethyl acrylate in the form of a quaternary ammonium salt or an acid addition salt and containing from 50 to 99 mol% of cationic groups with uniform copolymer distribution simultaneously more than 6 dl measured in g molar sodium chloride solution at 25 ° C and having a calculated cation number of more than 94% of the theoretical cation number are particularly well suited for flocculating colloidal slurries containing high volatiles and generally for precipitating colloidal suspensions as flakes and liquids.

When using copolymers according to the invention with a high charge density, for example for removing water from sewage sludge or industrial sludge, the doses used can be reduced and still ensure efficient and regular operation of the equipment: the filtrate tank does not clog but is suitable for volume and dryness, and therefore easy to handle. are suitable which allows the equipment to be quenched, and centrifugation results always above 98% in equipment equipped with successive decanters, clear filtrates always containing less than 1 g / liter of dry matter in equipment equipped with bandpass filters.

Reaction coefficients have been determined for the β and β monomer pairs: acrylamide and dimethylaminoethyl acrylate in the form of an acid addition salt with hydrochloric acid: AAM-CHA, acrylamide and dimethylaminoethyl β-acrylamide formed with methyl chloride quaternary salt of dimethylaminoethyl methacrylate formed with - AAM-CMM. The following values are obtained:

Table I

Monomer pairs Reaction coefficients _r_l_r_2_ 10 AAM-CHA 0.80 0.55 AAM-CMA 0.72 0.66 AAM-CMM 0.20 1.75 These determinations of reaction coefficients have been performed according to either A.J. Yezrielev1 in et Coll, Vysokomol.

Soedineniya, 1969, 11 (8) 1670, or according to the method of T. Helen et Coll. J. Polymer.Sei, 1977 15, 3047-3074.

From these reaction coefficients, curves are obtained which can be used to add suitable mixtures of substances to copolymers based on dimethylaminoethyl acrylate in the form of a quaternary ammonium salt or an acid addition salt, thus achieving a homogeneous distribution of cationic segments in the copolymer chains. Table II shows, as a function of the molar percentages of the cationic monomer in the copolymer, the amount of copolymer in percent with an assembly of +, to the nearest 10%, the desired composition.

67870

Table II

Mole percent% of a copolymer having a cationic mono- to the accuracy of 10% to the desired mer composition 5

AAM - CMA AAM - CHA AAM - CMM

30 99 99.8 8 50 89 91 15.7 70 61.6 86.2 36.9 10 80 98.9 22.9 90 96.4 98.6 94.4

Thus, it is noted that in the case of pairs AAM-CMA and AAM-CHA, the composition of the copolymer differs less from the initial composition of the mixture of monomers than in the case of the pair AAM-CHA. Thus, the copolymers obtained starting from the pairs AAM-CHA and AAM-CMA have a more regular distribution of cationic groups than the copolymers obtained starting from the pair AAM-CMM.

If calculated according to T.Alfrey and C.Price, J.Polymer.Sei. 1947, 2, 101, the coefficients e and Q, which determine the polarity of the ethylene bond and the reactivity of the monomers, respectively, starting from the reaction coefficients, give the following values:

Table III

monomers Q e 3Q AAM 1,120 0,190 CHA 1,663 1,096 CMA 1,907 1,262 CMM 6,804 1,215 5 67870

A high value of the coefficient Q indicates that the reactivity of the monomer, i.e. its tendency to join the radical, is strong. But the radicals corresponding to the monomers derived from methacrylic acid are tertiary, i.e. more stable than those derived from acrylic acid derivatives; thus, definitely a lower reactivity is obtained.

The copolymers according to the invention always have an intrinsic viscosity of more than 6 dl as determined by classical methods at 10 to 25 ° C in a molar solution of sodium chloride and a cation number of more than 94% of the theoretical cation number, whereas, as will be seen below, copolymers corresponding to pairs di-15-methylaminoethyl methacrylate in the form of an acrylamide quaternary ammonium salt or an acid addition salt does not have both of these properties simultaneously.

The theoretical cation number of a copolymer is called the number of milliequivalents theoretically present in a gram of copolymer.

For a copolymer containing x% moles of acrylamide, molecular weight A and y% moles of cationic monomer, the molecular weight B, i.e. a copolymer with an average molecular weight M of one group, is given by the equation M = xA + yB, the theoretical cation number is obtained from the equation:

Ct = ILX -

M

The cation number-3q of the copolymers according to the invention is determined according to the method described in "Mass of analytical organics, pharmacy and bromatology - JAGautier and P. Malangeau, 17, series, page 83, Masson et Cie, Editeurs, Paris". according to which the cation groups are calculated using a 0.004 M aqueous solution of an anionic surfactant, sodium dioctyl sulfosuccinate in a buffered solution of water-chloroform in the presence of methyl yellow. The measured cation number is expressed in milliequivalents per gram.

It can be seen that the copolymers according to the invention always have a measured cation number very close to the theoretical cation number, while the corresponding copolymers with methacrylates instead of acrylates have measured cation numbers close to the theoretical cation numbers only in copolymers containing a lot of cation. The measured cation number, which is close to the theoretical cation number, indicates a good distribution of cationic groups along the chains; when the cationic groups are grouped instead of evenly distributed, there are chains or pums to form spheres in which the measured cationic groups cannot be affected by the measured reactants and thus cannot function like the famous ones.

Table IV shows the intrinsic viscosity values j -i (Λ) expressed - theoretical cation number values - g 20 and the measured cation number values expressed in milliequivalents of cations per gram of copolymer for some homo- or copolymers derived from the following monomers, AMA, AAM, CMM, CHM: 7 67870 f-- '

,. „O T- Ln CM CO

! r — I b0 \ Ό ό = t as o - = r ~ N / fTl i —----- -

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B

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M d υ (M 4 1CN q- IA ^ i |! D il rt --6 ------- - ---- E-i j i f; ia ^ S 3 J, ™ ^

SS

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-p S rt: rt $ Q tn ‘d; o O o o o o 8 -h m ι, ιηοοο-οο as c; ^ ^

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* · Φ φ I

s φ; • h 6 ς s <<<ς: i p G c /) 2 Σ: e rn a: rt g 2 o υ υ o o! I ___________________________________i β 67870

The required working dose has been determined experimentally, K

T

expressed in kilograms of copolymer / tonne of dry matter in the sludge to ensure regular and efficient operation of the treatment plants without clogging or sticking of 5 filter cans to lane filters, with sludges of different origins: municipal sludge, sludges from industrial sludges and differently pre-treated sludges , stabilized sludges, biological sludges 10 with different dry matter concentrations Ms

and the amounts of volatiles relative to dry matter-M

to _v are between 50-85%.

M

s

The volatiles contained in the slurry, Mv are determined by making the slurry gaseous in an oven at a temperature of 575 ° to 25 ° C; it is expressed in grams / 100 grams of land per dry matter in the sludge.

Biolocrical sludges are defined as organic hydrophilic flats from industrially sourced and / or fully oxidized effluents from communities: discharges from breweries, dairies, petrochemical plants.

Stabilized sludges are defined as organic hydrophilic sludges, which mainly come from municipal wastewater treatment plants and which are aerobically digested, i.e. mineralized.

Digested sludges are defined as organic hydrophilic sludges which come primarily from municipal wastewater treatment plants and which have been digested anaerobically.

Table V combines the test results obtained either from the copolymers according to the invention or, for comparison, from the copolymers described in French Patent 2,390,983 or from homopolymers of a quaternary dimethylaminoethyl acrylate salt formed with methyl chloride 35, or methyl homopolymers CMA.

Table V 5

Sludge Biologize C K.,. ,. , Decayed j

7 ^ Stabilized sludges sludges I

quality sludges j i United- United States Community-j

Sludge Nutrition from nista pe-1 10 origin industry A A B B | be D;

Dry matter 2.5% 2.4ί 2.55% 4.4i! NE i lose weight. ~ 1 „„ 77 ~ 7 I Dry- '~~ 8h, 5% 71 *, 7ί 71.8% 53% pressures ____ 15! v.use -..... '1 dose

poly- K / T K / T K / T K / T

.ϊϋΕ ^ _._ ____ 100SCMA 2.5 3.5 3.4 30% CMA-20% AAM 2.65 3.25 2.5? 0jCMA-30iAAM 5 2.25 3 2.6 20 30% CMA- 40JAAM 2.55 3.25 2.4 50iCMA-50? AAM 3 3.25 2.1 30% CMA-70% AAM 2.75 (1) 3.25 (1) i 100JCMM 6 2.9 O) 3 .4 4.8 25 (l) The filter pack adhered to the filter cloth.

Table V shows the clear superiority of the copolymers according to the invention in the removal of water from sludges rich in volatile substances: sludges A from communities. When using copolymers according to the invention containing more than 50 mol% of cationic monomers, clogging of bandpass filters is completely avoided and a filter cluster with a suitable degree of dryness and volume can be easily removed.

10 67870

A copolymer containing 70 mol% CMA and 30% AAM is particularly suitable for this type of volatile slurry. Table VI shows the operating parameters for 5 municipal sewage treatment plants treating organic stabilized sludges containing

dry matter 2.04% and the ratio of volatiles as-M

to va substances, _v = 60%, and using copoly-M

sea CHA-AAM, pp. 70-30, as a dewatering agent from slurries. This treatment plant is equipped with a double-band filter with a constant fabric speed of 1 m / min.

15

Table VI

! . i! j Feed j Flocculation jCouple jute 20 feas5- Ms "" föpeus® · Application- m3 / hk / 100 r Kr Ms / h gentle dose Batch, m / ng / ιυυ g Kg ns / n substance substance cohti ± u ^ _: ____ quality________flow _SS & 11.35 16.9 191 70 * CHA- 322 1.7 13.3

30 * AM

15.77 16.9 266 "522 1.95 13.5 25 11.35: 20.4 232 100 * CHM 733.7 3.2 13.6 - * ---.» _____ _____I______

According to Table VI, in order to obtain a filtration tank with a dry matter of the same 13.5 to 0.2 g of dry matter per 100 grams of filtration tank, the use of polyelectrolytes, expressed in kilograms per tonne of dry matter in the slurry, is significantly lower with the polyelectrolyte 70 according to the invention. CHA - 30 AAM.

It is known that esters of acrylic acid in general and dimethylaminoethyl acrylate in particular are much more easily hydrolyzable than the corresponding esters of methacrylic acid 67870. By simply dissolving these substances in water, bringing the pH of the solution to 11, it is found that dimethylaminoethyl methacrylate hydrolyses very little at 20 ° C: 6% in 30 minutes, while in the same time 50% of dimethylaminoethyl acrylate is hydrolysed. . At pH 5.5, -6, the hydrolysis of dimethylaminoethyl acrylate is weaker, at 0.8% at 40 ° C and 3.8% at 60 ° C in one hour, but it is still 10 4-5 times faster than that of methacrylic acid. ester.

Similar results have been reported in the literature for the hydrolysis of polymers of acrylic and methacrylic acids and esters. For example, in the encyclopaedia KIRK-0THMER, the second edition, part 13, page 344, is cited as e.g. Studies by G.Smets et C011 J.Polymer.

Sci., 1959, 41, 375-80, which have shown that methyl methacrylate polymers are much more resistant to hydrolysis than methyl acrylate polymers and that these differences in behavior are large, as the latter are 98.7% hydrolysed within 30 minutes to 20 minutes when whereas the former have not hydrolyzed more than 11% in 16 h.

It is also known that the polymerization of acrylic acid derivatives is strongly exothermic; for example, the polymerization temperature of acrylamide is 19.8 to 0.7 Kcal / mol (FR 2246573). Thus, it must be possible to control the polymerization of dimethylaminoethyl acrylate in the form of a quaternary ammonium salt or an acid addition salt, especially since powdered copolymers can be obtained without damaging the cationic chain.

According to the prior art, various solutions have been invented to overcome this difficulty. U.S. Patent 4,138,539 discloses a continuous polymerization process comprising a mobile polymerization zone, but this process requires a considerable investment of material, which is not profitable through other factory production, as is the case with classical, multi-purpose material.

Another difficulty is to obtain the powdered polyelectrolytes according to the invention, which contain as little water as possible and do not require post-grinding, which means dust and very embarrassing screening waste for the user.

It has been known in the prior art to readily prepare copolymers of acrylamide and dimethylaminoethyl acrylate in the form of a quaternary ammonium salt or an acid addition salt in aqueous solution by copolymerization at a suitable pH; but in this way, even at low concentrations, gels are obtained which are almost impossible to convert into a powder. However, for industrial use, it is better for polyelectrolytes to be in the form of a powder, where they are easier and cheaper to transport than aqueous solutions.

The polyelectrolytes according to the invention can be obtained in any suitable manner. In a preferred embodiment, for example, copolymerization of acrylamide in the form of a quaternary ammonium salt or an acid addition salt with dimethylaminoethyl acrylate is carried out in the required proportions in an inverse emulsion, water in oil, (i.e. water with an organic , mainly between 4.5 and 6, after which the water is removed at a temperature below 80 ° C so as to avoid the phenomenon of complete hydrolysis. Removal of water can be accomplished either by azeotropic distillation with the solvent used during the polymerization, if the latter allows it, or by decantation, filtration, washing with a water-miscible solvent such as acetone, and drying the polymer on a fluid bed below 75 ° C.

13 67870 The organic solvent used is an aliphatic or cyclic hydrocarbon such as heptane, mixtures of aliphatic branched hydrocarbons Cig-C12 or cyclohexane.

Heptane or cyclohexane with which water can be azeotropically removed from the copolymer is preferred. The concentration of monomers in the aqueous phase may vary to 40-70% as indicated above, the mixture of monomers may contain 50-99% of cationic monomer expressed in moles.

As the initiator catalyst, any classical initiating system can be used, for example a photovoltaic catalyst in which light is present, azo compounds, peroxides, organic hydroperoxides (benzoyl peroxide, cumene hydroperoxide) and time persulphates, either alone or , such as tertiary amines, (dimethylparatoluidine, triethanolamine), organic salts and transition metal complexes (cobalt II-octoate, iron III-acetylacetonate), temporal sulfites, thiosulfates and metabisulfites, etc.

The emulsifiers used are, of course, substances with a low HLB (= hydrophilic, lipophilic balance, Hydrophilic lipophilic balance), mainly fatty acid esters of sorbitan, for example sorbitan monooleate.

The following examples are provided to illustrate the subject matter of the invention.

Example 1 - Copolymer AAM - CMA - 30/70 A solution of 4 g of sorbitan monooleate in 468 g of cyclohexane is poured into a 2-liter reactor and, after being evacuated with nitrogen, poured into a stirred atmosphere of 172 g of nitrogen. .8 g (0.89 mol) of methyl chloride quaternized dimethylaminoethyl acrylate, CMA, and 27.2 g (0.38 mol) of acrylamide, AAM, in 200 g of water, i4 67870 adjusted to pH 4.5. by adding dilute sulfuric acid.

A solution of 0.043 g of cumene hydroperoxide (70%) in 12 g of cyclohexane is then added with constant stirring under a nitrogen atmosphere and then, after a few minutes, a solution of 0.040 g of sodium metabisulphite in 10 g is added dropwise. of water. The polymerization reaction then begins and the reaction temperature gathers to 70-75 ° C in 5-10 min 10. Stir for 1 h at boiling point and then remove the water by azeotropic distillation until the residual water is 15%. The reaction solution is then cooled to ambient temperature and filtered, the filtrate is washed with 3-hexane (170 ml) and finally dried on a fluid bed at 95 ° C for 30 min. In this way, AAM-CMA 30/70 copolymer is isolated, which is a powdery, 96% dry extract which is completely soluble in water and has a specific viscosity of 8.5 measured at 25 ° C in a 20 molar sodium chloride solution and a measured cation number of 4, 2 meq / g or 94.5% of the theoretical cation number.

Examples 2-3: Copolymers AAM-CMA - 20/80 and 40/60 Work as in Example 1, but using dimethylaminoethyl acrylate in the form of a salt quaternized with 0.95 mol of methyl chloride, CMA and 0.24 mol of acrylamide, AAM, i.e. 0.83 mol CMA and 0.55 mol AAM. In this way, copolymers 30 AAM-CMA are obtained which contain either 80% CMA and 20% AA in a molar ratio, or 60% CMA and 40% AAM. These copolymers have a measured cation number of more than 94% of the theoretical cation number.

Example 4 - Copolymer AAM - CHA 30/70 35 Work as in Example 1, but using 0.95 mol of dimethylaminoethyl acrylate hydrochloride and 0.41 mol of acrylamide and, if necessary, adjust the pH of the aqueous solution to 4.58 with dilute hydrochloric acid. with dilute ammonia.

In this way, the powdered copolymer AAM-CHA - 30/70 is isolated, the intrinsic viscosity of which, measured at 25 ° C in a molar sodium chloride solution, is J 1 8.8 - and the measured cation number is 94.5% of the theoretical cation number.

The substances obtained as in the above examples have proven to be effective in their use, as shown in Tables V to VI above.

They have also given good results when used for emulsifying liquids, for example industrial liquids based on petroleum derivatives or emulsions obtained from underground layers and the like.

It is to be understood that the invention has been described for purposes of illustration and that any useful modification may be practiced without departing from the scope of the invention as defined in the following claims.

Claims (5)

67870 1. Powdered, water-soluble cationic polyelectrolytes consisting of copolymers of acrylamide and dimethylaminoethyl acrylate in the form of a quaternary ammonium salt or an acid addition salt having a polyelectrolytic intrinsic viscosity of more than 6 at 1 ° C measured at 25 ° C 90% of the theoretical value, 10 characterized in that they contain in a molar ratio more than 50% of cationic groups regularly distributed along the chains of the copolymers. Cationic polyelectrolytes according to Claim 1, characterized in that the dimethylaminoethyl acrylate is in the form of an acid addition salt formed with hydrochloric acid. Cationic polyelectrolytes according to Claim 1, characterized in that the dimethylaminoethyl acrylate is in the form of a quaternary salt formed with methyl chloride. Use of powdered cationic polyelectrolytes according to any one of claims 1 to 3, wherein said polyelectrolytes are used in an amount of 1 to 5 kg / t of dry solids to agglomerate emulsions and / or highly colloidal hydrophilic suspensions containing very high volatiles and / or having a high zeta potential, such as sludges which are organic, inorganic, biological, stabilized sludge or digested sludge. Use of cationic polyelectrolytes according to claim 4, such that the content of volatile substances, determined by gasification of the sludge to be treated in an oven at a temperature of 575 ° to 25 ° C and expressed in grams per 100 g of solids in said slurry, is greater than or equal to 50 %.