Note: Descriptions are shown in the official language in which they were submitted.
~224~02
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Methacry].amidoalkanesulfcnic and -phosphonic acids are
known (European Patent No. 10,355). Because there is in-
terest in similar polymerizable phosphonic acids having
corresponding improved properties for use in the industrial
practice, especially an increased stability to hydrolysis
of the amide bond, 2-methacrylamido-2-methyl-propane-
phosphonic acidwas prepared which hitherto was unkown.
Subject of the invention are 2-methacrylamido-2-
methyl-propanephosphonic acid of the for.mula
CH O CH O
1 3 ll 1 3 ll
CH2 = C - C - NH - C - CH2 - P(OH)2 (I)
CH3
and the sa].ts thereof.
The 2-methacrylamid~2-methylpropanephosphonic acid
is prepared according to the principle of the Ritter re-
action from. methacry].onif,rile and 2-methylprop-1-ene-1-
phosphonic acid or isomeric 2-rnethylprop-2-ene-1-nhos
phonic acJd, or mixtures of the two phosphonic acids,
in the presence of stron~ acids such as H2S04, H3P04,
HC].04, H~, according to the following reaction scheme:
CH3 O
~C = CH - P(OH)
ICH3
CIH3 J + H20
CH2 = C - Ci~ + or > ~ S0
C ~ CH - P(OH)
C~2
The 2-~lethyl-prop-1-ene- or 2-rnethyl-prop-2-ene-phosphonic
acids used are easily obtainable by hydrolysis of the
~ . . , .. , ~ . . . .... . . . .. . . . . . . . . . . .
~224802
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correspollding phosphonic acid dlchlorides, which 2-methyl-
propene~ hosphonic acid dichlorides are already des-
cribed in detail in the literature (U.S. Patent No.
2,471,472; L. Maier, Phosphorus 5, 223 (1975)).
The isomer mixture of the 2-methyl-propene~ phos-
phonic acids is reacted with methacrylonitrile in a mo-
lar ratio of about 1 : 1. An additional solvent is not
necessary; however, an excess of the strong acid or of
methacrylonitrile required for the reaction may serve as
a solvent.
The reaction temperatures are from 10 to 90C; pre-
ferably, the tempera'ure is raised during the reaction
from about room temperature to about 60 - 70C towards
the end. The reaction time ranges from 1 hour to several
days; preferably, it is from 12 to 24 hours.
Suitable strong mineral acids are those cited above
and sui~on9c acid group-containing ion exchangers, ge-
~erally in aqueous form; preferably, concentrated sul-
furic acid is used which contains the one equivalent of
water required for the reaction. The mineral acid is
used in an amount at least equimolar to that of the
starting compounds.
The salts of the phosphonic acid I are prepared ac-
cording to known methods, for example by reaction with
equivalent amounts of a metal hydroxide or carbonate
from an aqueous or alcoholic solution.
Suitable metal hydroxides are alkali or alkali
earth mel;al hydroxides~ zinc, aluminum or iron hydroxides,
especially sodium or potassium hydroxide, or ammonium
hydroxides opticnallly substituted by (Cl-C4)-alkyl,
especially ammonium hyd-.oxide.
Salts of the compounds I according to the invention
are for example: monosodium, monopotassium, monolithium,
monoammonium, magnesium, calcium, aluminum, ~inc, iron,
disodium and dipotassium salt.
.
i:~2480%
- 4 YIOE P3fE' 062
The compound of the for~ula I and its salts are e;;tre-
mely stable to hydrolysis and are valuable monomers for
the manufacture of copolymers. Thus, copolymers of
2-methacrylamldo-2-methylpropanephosphonic acid and
acrylonitrile have a reduced flammability. Copolymers
with acrylamide can be applied as dyeing auxiliaries~
and copolymers with acrylic acid may be used as scale
inhibitors.
The following examples illustrate the invention~
Example_l
1041 g (5 mols) of PC15 were sus~ended in 205 1 of
anhydrous toluene, and 281 g (5 mols) of isobutene were
introduced at 10 - 15C. The batch was stirred for ~0
minutes at 15C, and subsequently S02 was introduced at
10 - 15C until a clear solution has forrned.
Toluene and SOC12 were dlstilled off. In order to
split off the hydrogen chloride, the ~esidue was heated
for 8 hours at 270 mbar and 18~C with addition of 3 g
of triphenylphosphane.
Distillation yielded 660 g of a mixture of the iso-
meric 2-methyl-propene-phosphonic acid dichlorides. B.p.
at 16 mbar: 90 - 93C. Yield: 76.3 %.
500 g (2.89 mols) of 2-methy1propene-phospholllc
acid dichloride were added dropwise to a solutlon cf' 231 g
(5.78 mols) of sodium hydroxide in 600 ml of wat;er at
20C. Subsequently, the batch was concentrated by evapo-
ration in vacuao and the remaining phosphon~c acid was
extracted with 1,000 ml of acetone. The sodium chloride
residues were after-washed with 2 ~500 ml portions of
acetone, the combined filtrates were concentrated by
evapora~ion and finally dried for 4 hours in a high va--
cuum at 50C.
Yield: 38~ g (98.5 % of the theory).
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0.5 g of phenothiazlne and 98 g (1.47 mol) of methacrylo-
nitrile were added to 100 g (0.735 mol) of the above
obta~ned 2-methyl-propene-phosphonic acid (mixture of
isomers) and a mixture of 75.8 g (0.735 mol) of 97 %
sulfuric acid and 13.2 g (0.735 mol) of water ~-as added
dropwise at 20 - 30C. The reaction mixture was kept at
25 - 30C for 16 hours, heated to 60C over a period of
4 hours and maintained at 60C for a further 16 hours.
The cooled residue was suspended in 5O0 ml of water,
58.8 g (1.47 mol) of sodium hydroxide in 100 ml of water
were added and the water was substantially distil:Led off
in vacuo. The residue was extracted with 3 250 ml por-
tions of isobutanol, the isobutanol phase was concentra-
ted by evaporation and 2-methacrylamido-2-methyl-propane-
phosphonic acid was preclpitated by addition of 1,000 ml
of acetone.
Yield: 109 g= 67 % of the theory. M~po 149 ~ 151C.
Example 2
200 mg of phenothiazine and 22.1 g (0.33 mol) of
methacrylonitrile were added to 45 g (0.33 mol) of 2-
methyl-propene-phosphonic acid (according to Example 1).
A mixture of 33.3 g (0.33 mol) of 97 % sulfuric acid and
5.9 g (0.33 mol) of water wa~ added dropwise at 20C.
25 After having lcept the batch for 16 hours at 20 - 30C,
the temper2tt1re was raised to 60C within 4 hours and
this temperature was maintained for a further 16 l~ours.
The cooled reaction batch was dissolved in a mixture of
21 g of water and of 200 ml of methanol and the sulfuric
acid was neutralized by addi-ng a solutiorl of 26.4 g
(0.66 mol! of ~laOH, 21 ml of water and 200 ml of metha-
nol. Sodium sulfate was filtered off and the filtrate
was concentrated by evaporation. 2-Methacrylamido-2-
methyl-propane-phosphonic acid was precipitated by adding
250 ml of acetone.
Yield: 44.3 g (60.5 % of the tl;eory).
1224802
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Example 3
500 ml Or de-ionized water were given into a 2 1
polymerization flask provided with a stirrer, a ref`lux
condenser, a gas inlet tube and an electrically heated
water bath and 80 g of acrylamide and 10 g of 2-meth-
acrylamido-2-methylpropane-phosphollic acid (~IA~lPP) were
dissolved therein while stirring and introducing nitro
gen. After addition of 5 ml of isopropanol the tempera-
ture in the flask was raised to 70C. A solution of 0.25 g
of ammonium peroxodisulfate in 10 ml of water was added
dropwise wlthin 10 minutes. wherebg the temperature of
the reaction mixture rised to 75C. After the tempera-
ture had dropped, stirring was continlred for 2 hours at
a bath temperature of 80C. A clear viscous solution
having a pH of 2.21 and a viscosity according to Brook-
fleld Or 12172 cp was obtained.
A fabr~c consisting of 50 ~ ol polyester and 50 %
of` cotton was impregnated on a foulard at a liquor uptake
of 60 % with a liquor consisting of
15 g o dyestuff Disperse Red 90,
15 g of dyestuff Vat Red 51,
10 g of the polymer solution prepared as indicated
above and
950 g of water,
and then dried on a stenter. A dying l~as obtained with
the same color depth on the upper and lower side of the
fabric.
Exa_ple 3
A copolymer of 50 weight parts of 2--methacrylamido-
2-methylpropanephosphonic acid and 50 weight parts of
acrylic acid was prepared by raAical initlated solution
polymerization in a water/isopropanol mixture at 85C.
The resulting copolymer having a ~ value of 18
(according 'o Fi~entscher) was tested according to NACE
standard T~-03-74 (NACE= National Associatiorl of Corrosion
.
1224~302
7 - HOE 83/F 062
Engineers, 1440 South Creek, Hiouston, Tex.) as scale in-
hibitor for the prevention of calclum sulfate and calcium
carbollate precipitates in aqueous solutions.
With addltion of lO ppm of polymer according to the
test prescription, a commercial product having the trade
name ( )ACRYLON A 002 of Messrs. PROTE~ was tested against
a copolymer o~ the invention having the cornposition as
above.
¦ Copolymer of ~ ( )Acrylon
¦ MAMPP - ~ A 002
¦ acrylic acid ¦
Ca sul~ate ~etention value ~ 4872 mg~l ~ 3833 mg/l
ca carbonate retention value¦ 3711 mg/l ¦ 2965 mg/l
