Note: Descriptions are shown in the official language in which they were submitted.
W O 96!00744 PCT/BS95J08365
2193198
- 1 -
PROCESS FOR PRODUCTION OF A
J~OLYSUCCINIMIDE AND DERIVATIVES THEREOF
Field of the Invention . __
This invention relates to the production of a
polysuccinimide and derivatives thereof. More
particularly, this invention relates to the production
of a polysuccinimide or a derivative-thereof by thermal
polymerization of precursor monomers in a efficient
1D manner.
Backaround of the Invention .,..,..._... __,.
Methods for the preparation of polysuccinimide
by the thermal polymerization_of ammonia salts of malefic
acid are known in the art. Illustrative of such methods
are those described in U.S. Patent No. 4,839,461 to
Boehmke,-U.S. Patent No. 5,296,578 to Koskan et al. and
U.S. Patent No. 5,288,783 to Wood. However, as the
thermal polymerization of ammonium maleate compounds
proceeds, the mass of reactants and reaction products
20-- becomes extremely viscous and virtually impossible to
process. The result is an incomplete polymerization.
The present invention overcomes the
aforementioned difficulties and-provides a manufacturing
process during the course of.which stirring is not
-needed. .
~_umma~y of the Invention . _ _"_
Polysuccinimide in good yields is produced by
thermal polymerization of a unsaturated organic
polysuccinimide precursor in_an externally heated plate-
type reactor at temperatures sufficient to initiate
polymerization and to form a brittle solid, preferably
in the range of about 140°C. to about 350°C., more
preferably about 185°C. to about 300°C. The precursor
preferably is an.ammonium salt of malefic acid. However,
WO 96/00744 PCTlgJS95108365
2193198
_ 2 _
other-precursors such as ari ammonium salt of fumaric
acid,-and the like, can be utilized as well.
The thermal polymerization can be carried out
as a continuous, semi-continuous, or batch-process, with
or without a catalyst present.
Brief Description of the Drawinas
In the drawings,
FIGURE 1-is a schematic process flow diagram
showing the overall process.. of this invention; and-
FIGURES 2-11 are heating curves for a group of
experiments reported herein and show reactant
temperature as a function of elapsed time in a plate-
type reactor.
Detailed Description of Preferred Embodiments
The polysuccinimide precursor suitable for the
purposes of the present invention is an unsaturated
organic acid or salt that is either commercially
available, or one that can be prepared, e.g. by reacting
malefic anhydride or malefic acid with ammonia or ammonium
hydroxide. A.variety of such processes for preparation
are known in the art. However, the thermal
polymerization of such precursors to polysuccinimide has
met with limited commercial success due to the formation
o~ highly viscous intermediates that are very difficult
to handle and that preclude an effective release of
thermal polymerization byproducts. The present process;
on the other hand, minimizes such processing
difficulties and provides for easy recovery of the-
thermal polymerization product, i.e., polysuccinimide,
in good yields by using a plate-type reactor.
Specifically, the polysuccinimide precursor,
prepared in any convenient-manner, is-passed-through a
hot reaction zone as a relatively thin layer on a plate,
usually in intimate contact with a solid heat transfer
surface; not exceeding about 2 inches (about 5
~7V0 96100744 219 3 ~ 9 8 pCT~S95/08365
- 3 -
centimeters) in thickness, and is maintained in the
reaction zone at a temperature sufficient to ir_itiate
polymerization and to form a brittle solid, preferably
in the range of about 140°C. to about 350°C. for a time
period in-the range of about 15 minutes to about 5
hours, preferably for about 30 minutes to about 120
minutes.
In the absence of a thermal polymerization
catalyst, the more preferred temperature range is about
185°C. to about 300°C., most preferably about 250°C.,
for about 60 minutes.
The-present thermal polymerization process is
particularly well suited for use with precursors that
are ammonium salts of malefic acid, malic acid, fumaric
acid, maleamic acid, itaconic acid, citraconic acid, and
mixtures thereof. Illustrative such salts are
monoammonium maleate, diammonium maleate, monoammonium
fumarate, diammonium fumarate, monoammonium maleamate,
and derivatives of the foregoing.
Additionally, the thermally polymerized
polysuccinimide can be derived from a mixture of
reactants that form one or more intermediates which, in
turn, can-be polymerized to polysuccinimide.
Illustrative such mixtures are malefic anhydride and
ammonium carbonate, citraconic anhydride and ammonium
carbonate, itaconic anhydride and ammonium carbonate,
malefic anhydride and asparagine, citraconic anhydride
and asparagine, itaconic anhydride and asparagine,
malefic anhydride and ammonium maleamate, citraconic
anhydride and ammonium maleamate, itaconic anhydride and
ammonium maleamate, malefic anhydride and monoammonium
aspartate, citraconic anhydride and monoammonium
aspartate; itaconic anhydride-and monoammonium
aspartate, malefic acid and ammonium carbonate,
citraconic acid and ammonium carbonate, itaconic acid
WO 96/00744 PCTIUS95/08365
2193198
- 4 -
and ammonium carbonate, malefic acid and asparagine-;
citraconic acid and asparagine, itaconic acid and '
asparagine, malefic acid-and ammonium maleamate,
citraconic acid and ammonium maleamate, itaconic acid
and ammonium maleamate, malefic acid and monoammonium
aspartate, citraconic acid and monoammonium aspartate,
itaconic acid and monoammonium aspartate, malic acid and
ammonium carbonate, malic acid and asparagine, malic
acid and ammonium maleamate, malic acid and monoammonium
aspartate, fumaric acid and ammonium carbonate, fumaric-
acid and asparagine,-fumaric acid and ammonium
maleamate, fumaric acid and monoammonium aspartate, and
the like. - _
The hot reaction zone can be a furnace cr oven
into which the precursor is introduced as arelatively
thin layer of a reaction mass on a plate-type reactor,
e.g., on trays, on a continuously moving conveyor-belt
(stainless steel or temperature-resistant composite), or
in any other convenient manner, and heated sufficiently
for polymerization-to take place. The furnace
atmosphere can be inert, if desired, or can be enriched
with ammonia. Process pressure in the hot reaction zone
can be atmospheric or sub-atmospheric.
Upozi reaclW ng-polymefiaation temperatures, the
reaction mass begins to foam, releasing polymerization
by-products suchas water.The-thermal polymerization
product obtained in the reaction zone is a brittle mass
that can be readily recovered and comminuted to a-
desired particle size for use, or for hydrolysis to
polyaspartic acid nr-a saltthereof in a known manner. ,
The present process provides-the required heat
input to complete the-polymerization tn polysuccinimide ,
quickly and in relatively inexpensive equipment. :u11
advantage is taken of the fact that the precursors of
polysuccinimide are solids-that can be easily spread in
'WO 96/00744 PCTlUS951D8365
2193198
_ 5 _
a relatively thin layer on a heat transfer surface
either as a powder, slurry or paste and then heated to
form a melt of reactants. The moisture content is not
critical for this purpose. This--thin layer provides
sufficient surface for the transfer of the required heat
without requiring mixing. In,_addition, as the
polymerization reaction is completed, the thin layer of
reactants becomes a expanded brittle porous mass that is
easily removed from the heat transfer surface and ground
into a free flowing powder that can be easily fed to a
hydrolysis reactor. As the temperature of the reactant
and mixture rises, the reactants become a melt. Thus,
no effort needs to be made to-agitate the reactants
because it is not necessary to do so for heat transfer
purposes.Sufficient heat transfer is provided by
heating from both below by the heat transfer surface and
from above the reacting mass itself by radiant heat,
conduction and/or convection. -This can be most easily
and economically achieved by using a continuous gas
fired oven such as is used in baking or curing.
In an embodiment of the present process, the
polysuccinimide precursor is spread on a continuous belt
or the like at the inlet to the oven, then-enters the
reaction zone-which is heated by gas firing or a similar
expedient. The belt speed is-adjusted so that the
polymerization reaction is completed while in the
reaction zone. The obtained polysuccinimide product
then enters a cooling zone where air or a water spray
can be used to reduce the product temperature and to aid
a 30 in the release of the product from the belt.
As shown in FIGURE.1, the polysuccinimide
precursor feed is deposited on a conveyor 12 such as a
stainless steel conveyor belt and passed through furnace
14 that provides a hot reaction zone-for the feed.
Produced polysuccinimide is removed from conveyor 12 and
W O 96100744 PCTIUS95/08365
2193198
- 6 -
comminuted to a desired particle size in grinder lfi. If
conversion to polyaspartic acid or a salt of
polyaspartic acid is desired, the comminuted
polysuccinimide is hydrolysed-in hydrolyzer l~. '
In addition to the continuous-embodiment, the
present process can also be practiced by feeding the
precursor to trays on a continuous chain which trays are
then are moved through a hot oven. Cooling,of the
produced polysuccinimide can be accomplished by spraying
water or air onto the trays at the downstream end-of the
reactor oven or furnace. The trays are upended as they
exit the oven and return to-the upstream part of the
oven on the underside of the chain.
Additionally, the present process can be
practiced in a batch oven. In-this particular
configuration, the precursor is spread to the desired
thickness described hereinabove on trays. These trays
are then placed on a rack and wheeled into a-hot oven.
The oven is shut down upon completion of the
polymerization, the obtained polymer cooled, removed
from the trays, and ground to a desired particle size.
The resulting polysuccinimide can be base
hydrolyzed to polyaspartic acid, or to a polyaspartic
acid salt preferably using an alkali metal hydroxide,
e.g., sodium hydroxide, and the like. While not a
simple reaction, the base hydrolysis generally follows
an Arrhenius profile where-the optimum temperature for
the hydrolysis is about 70°C.
To hydrolyze, a suspension of polysuccinimide
in water is made with vigorous mixing in order to wet
the solids. flank car caustic is the preferred
hydrolysis base and is added to the suspension at a ,
controlled rate. The hydrolysis reaction is monitored
so that the pH value of the suspension averages about
9.5 and the temperature-does not exceed about 80°C. The
CVO 96100744 PCT/US93/08365
2193198
amount of base used for the hydrolysis is at least
' atoichiometric with respect to polysuccinimide present.
Solution strengths from about 5 to about 50 weight
percent are obtained with a preferred range of about 40
to about 45 weight percent solids.
The present invention is further illustrated
by the examples that follow.
EXAMPLE 1: Synthesis of Dry Monoammonium Maleate.
Isolation by Precipitation.
Malefic anhydride briquettes (400.64 g; 4.09
mol) were crushed into small pieces and placed in a
reaction vessel (2 L). Water (600 ml) was added to the
vessel to give a suspension. -The vessel was immersed in
an ice-water bath. The suspension was stirred with a
mechanical stirrer until the temperature of the
suspension was about 13°C. Next, aqueous ammonia (29.8%
w/w; 256.22 g ; 4.48 mol ammonia) was added to the
stirred reactants dropwise over a period of 2.5 h. The
temperature of the reaction contents was maintained at
around 5 to 15°C. After the ammonia addition was
complete, the reactants were warmed to room temperature.
The resulting suspension was filtered and the recovered
solid was allowed to air dry. The acidic filtrate
(approx. pH 4) was concentrated in vacuo and the
resulting suspension was filtered. The obtained solid
was air dried. The filtrate volume was 150 ml. The two
air dried solids were combined and dried for an
additional time (40°C; 3 h) to give colorless crystals
(352.8 g). The product, monoammonium maleate, was
characterized by TLC (1:5 MeOH:EtOAc; Polygram SiO~; Rf
0.09) and infrared spectroscopy. The product, when
dissolved in water, gave an acidic litmus test. A Rarl
Fisher titration showed that product contained 0.1% w/w
water. A sodium hydroxide titration indicated that the
WO 96/00744 PCT/US95108365
2193198
_a_
product contained 96% monoammonium maleate and 4%
diammonium maleate. '
EXAMPLE 2: Isolation of Dry Monoammoainm '
Maleate by Spray Drying
A concentrated filtrate containing
monoammonium maleate (152 g) similar to the one
described in Example 1 was diluted with water to give a
final volume of 500 ml (0.304 g/ml). The solution was
dried-in a commercial spray drier (BUChi Mini, atomizer
flow setting 800, aspirator setting wide open) to give
colorless powders that were confirmed as monoammonium
maleate. Settings and recoveries are shown in Table 1,
below.
TABLE 1
Svrav Drvine Conditions and Results for
Bxamole 2
Amount Addition
Pump Inlet Outlet Sotn Added Rate Wt. Recovery
Setting Temp (C) Temp (C) (ml) (mllmin) Product (%)
(g)
8 130 80 60 8.6 3.83 21
8 180 120 60 $.6 1:48 8.1
8 205 139 60 - . L03 5.6
8 96 57 60 10 7:43 41
4 99 71 60 6.7 7.46 41
EXAMPLE 3: Synthesis of wet Monoammonium Maleate.
Isolation by Precipitation.
Deionized water (21.8 kg) was added to a
chilled 20-gallon jacketed reactor. Next, crushed
malefic anhydride powder (21.8 kg;-222.28 mol)
was added
to the reactor. The resulting suspension was
stirred
with a mechanical stirrer- and was cooled to . Next,
15C
aqueous ammonia (30 % w/w;14.08-kg;-244_.89 mol) was
slowly added to the stirred reaction contents means
by
WO 96100744 PCTlUS95108365
2193198
_9_
of a dip tube over a one hour-period. The temperature
of the reactor contents was maintained below 30°C during
this time. After the ammonia addition was completed,
the resulting suspension was filtered. The wet solid
was stored in a drum. Three additional experiments were
conducted using the above procedure and the solids were
combined with the solid obtained from the first
experiment. The wet solids from all four experiments
were allowed to air dry for two days to give a moist
colorless product (56.3 kg). The product was identified
as monoammonium maleate by TLC (1:5 MeOH:EtOAc; Polygram
SiOz; Rf 0.09) and was found to contain 10 % water by
weight by Karl Fisher titration_ A sodium hydroxide
titration of the obtained product indicated that the
product contained 93.4 % monoammonium maleate and 6.6 %
diammonium maleate. -
EXAMPLE 4: Synthesis of Diammonium Maleate.
Malefic anhydride (158.94 g, 1.62 mol) and
water (150 ml) were combined in a 1-liter flask and
stirred to give a suspension. An ice bath was used to
cool the suspension to 10°C. Next aqueous ammonia
(29.7% w/w; 205.0 g; 3.57 mol) was added to the-mixture
over a one-hour period and the-resulting solution was
brought to room temperature. The solution was rotary
. evaporated (-80 KPa vacuum, 70°C) to give a moist solid
that was washed with two portions (30D ml each) of
acetone and air dried to give a very slightly pink
colored solid (210.48 g). The product, when dissolved
in water, gave a neutral pH toward litmus. The product
contained 1.8 % water by weight by Karl Fisher
titration.
WO 96f00744 PCTIUS95/08365
2193198
- 10 -
EXAMPLES 5-25: Synthesis of Polysuccinimide
by Layer Polymerization.
General Procedure: A Kenmore-convection oven
with a heating coil at the bottom of the oven was
preheated to a nominal predetermined setpoint
temperature. During this time three.aluminum pans [28.5
x 10.5 x 2 cm (1 x w x h)] were filled with the ammonium
maleate salts described in the previous examples. In
some of the experiments, the temperatureofthe inside
bottom surface of the pans containing the salts was
measured using a specialized surface. thermocouple probe
(Omega Scientific, model CO1, type K). The three pans
were placed next to each-other on the same rack in the
oven. The height of the rack above the heating coil was
13 cm. The temperature of the oven-was measured with a
thermocouple probe (Type R) positioned above (-.3 cm) the
surface of the contents in each pan.- There-was no
significant variation in the oven-temperature above each
of the three pans. The pans-were kept in the oven for a
predetermined reaction time. After this time had been
reached, the three pans-were quickly removed from the
oven, cooled to room temperature, and the products were
crushed to a fine powder and weighed. ,
The products were analyzed for molecular
weight by size exclusion chromatography. In this -
procedure the-product (Q.5 g) was_combined with sodium
hydroxide solution (1 N; 5.2 ml) and stirred to give a
solution. A portion of this solution (1.0 g) was
combined with potassium phosphate dibasic solution (0.1
M, 5.5 g). The resultant admixture was filtered through
a 0.45 ~m filter lnylon) and subjected to instrumental
analysis. The instrumental setup consisted-of (1) an
HPLC pump (Shimadzu model LC-lOAD), (2)-a mobile phase
(0.05 M KH2P09 solo.) which-carried the analyte (20uL)
at a rate of 0.4-ml/min, (3) two size exclusion
dV0 96!00744 PCT/US95I08365
2193198
- 11 -
chromatography colum.~~ (SynChropak GPC 100, GPC 500),
and (4) an ultraviolet (220 nm) detector. The
instrument was standardized-using sodium polyacrylate
' standards (Polysciences, Inc.) of narrow molecular
weight distributions. Weight average (Mw) and number
average (Mn) molecular weights wexe obtained using an
algorithm in the data handling system (Hitachi D-2520
GPC integrator).
The conditions and results for each
polymerization reaction for Examples 5-25 are shown in
Table 2, below.
WO 96100744 21 g 3 ~ 9 8 PCTIUS95108365
- 12 -
TABLE 2
Co nditionsd Resultsolymerization Reactions '
an of P for
Exari~les
5-25
Starting Loading NominalTina
a
Mtl. Weightg reactantlOven in Weight Weight
,
from Loadedcm' Temp Oven Product Mwl Loss
Ex. Example (g) surFace (C) (h) (g) Mw Mn (%)
5 3 75.22 0.25 185 0.5 53.82 871 3.0 28.4
6 3 151.600.5 185 OS 121.10S76 2.2 20.1
7 3 300.011.0 185 0.5 265.23366 1.7 11.6
1 8 3 75.04 0.25 205 0.5 49.79 1497 3.7 33.6
0
9 3 150.010.5 205 0.5 103.221146 3.5 31.2
3 300.041.0 205 05 234.52534 2.1 21.8
11 3 75.15 0.25 250 0.5 50.63 1967 3.3 32.6
12 3 150.030.5 250 0.5 98.90 IfilO3.3 34.1 -
_
13 3 300.121.0 250 OS - 216.171088 3.3 28.0
. -
14 3 75.31 0.25 305 0.5 44.49 2059 1.9 40.9
15 3 150.300.5 305 0.5 88.34 2152 2.4 41.2
16 3 300.12L0 305 0.5 188.131750 3.9 37.3
-=
17 3 75.12 0.25 ZOS - 1.0 47.29 1694 3.7 37.0
-
2 18 3 150.640.5 205 I-0 - 96.14- 2.8 36.2
0 1638
19 3 300.121.0 205 1.0 209.081001 3.0 30.3
3 75.03 0.25 250 1.0 45.78 -20392_8 37.7
21 3 150.080.5 250 1.0 93.25 = 2S 37.9
2043
22 3 300.221.0 250 L0 193.601863 3_6 35.5
2 23 4 149.940.5 250 0.5 97.95 1266 2.8 34.7
5
24 I 150.330.5 250 D_5 110.93._1588- 26.2
_ 4.0
3 149.980.5 250 0.5 97.15 1618 4.I 35.2
WVO 96100744 PCTlUS95/08365
2193198
- 13 -
Heating curve and/or oven temperature data for
Examples 5-25 are presented in-FIGURES 2-8 as follows:
Examples 5-7 FIGURE 2
Examples 8-10 -FIGURE 3
Examples 11-13 FIGURE 4
Examples14-16 FIGURE 5
Examples 17-19 FIGURE 6
Examples 20-22 FIGURE 7
Examples 23-25 FIGURE 8
Discussion of Examples 5-25
Examples 5-7
FIGURE 2 shows the temperature above the pans
containing monoammonium maleate. As can be seen from
15- - the data, the temperature was uniform above each of the
pans-throughout the experiment.
The data from Table 2 clearly shows decreasing
Mw with increasing loading. The data also shows
decreasing weight loss with increasing loading. The
relatively lesser loading facilitates complete
conversion to occur within a relatively shorter time
period at substantially constant heat transfer.
Examples 8-10
FIGURE 3 shows the temperature above the pans
in Examples 8-10. The temperaturesabove each of the
three pans are uniform and support the conclusion that
the oven provides a uniform heating environment.
FIGURE 3 also shows the temperature in the
pan corresponding to Example lp_-The-curve obtained has
four distinct portions. The first portion is a region
of rapid temperature increase.- The second portion of
the curve is a region of slower temperature increase.
This second region potentially corresponds to the
removal of free waters of association from the starting
monomer. The third portion of-the curve is a region of
R'O 96100744 PCT/US95108365
2193198 a
- 14 -
faster temperature increase. This third region
potentially corresponds to the point at which the -
polymerization reaction-begins. The fourth portion of -
the curve is a region of slower and leveling temperature
increase. This potentially corresponds to the point at
which waters of imidization are evolving and the
completion of-the reaction.-
The data from Table 2 clearly show a
decreasing Mw with increasing loading. Thedata also
show decreasing weight lose with increasing loading.
The relative ordering is attributed to faster heat
transfer with lower loading.
Examples 11-13
FIGURE 4 shows the heating curves for Examples
11-13. As is seen from the data, the sample with the
lowest loading (0.25 g/cm',-Example 11) reached the four
regions of the heating curve more quickly than the
samples containing the higher loading levels (Examples
12, 13). Accordingly, from Table 2, the Mw obtained for
the product o~ Example 11- is higher than the Mw's
obtained for the products of the other two examples.
Examples 14-lb
FIGURE 5 clearly shows differences in heating
rates of the samples from Examples'14-16. The heating
rate decreases with increasing loading-and is again
. attributed to heat transfer differences.
Summary of Examples 5-16
The data for EXamples 5-16 (Table-2) clearly
show that Mw increases with increasing-oven-temperature
and decreasing loading.
Examples 17-19 -
FIGURE 6 shows the standard four region -
heating curves for the-three loadings. These reactions,
conducted for one hour at a nominal oven temperature of-
205°C, show increasing Mw with decreasing loading.;- As -
'PVO 96100744 PCTIU595I08365
2193198
- 15 -
discussed before, a similar trend is obtained for
Examples 8-10, conducted for 0.5 hour at a nominal oven
temperature of 205°C. Differences in the two data sets
' were that the Mw difference between Examples 17 and 18
was smaller than the Mw difference between Examples 8
and 9. These differences are believed to be due to the
longer reaction time.
Examples 20-22
FIGURE 7 shows that the final oven temperature
i0 was reached for the two lower loadings (Examples 20, 21)
but was not reached for the highest loading (Example
22). Differences in-the Mw between the products of
these examples are much smaller than the differences
obtained between Examples 11-13. Again, these
differences are probably due to -the longer reaction
time.
Examples 23-25
FIGURE 8 shows the difference between heating
curves obtained for the products of dry diamroonium
maleate (Example 23), dry monoammonium maleate (Example
24), and wet monoammonium maleate (Example 25).
The heating curve for the reaction of
diammonium maleate (Example 23) consists of a straight
increase in temperature with time. The curve for
Example 24, dry monoammonium maleate, is similar to the
curve for Example 25, wet monoammonium maleate, in that
they both have the previously described four region
appearance.
The infrared spectrum of the product of -
Example 23-confirmed that it was polysuccinimide,
however its Mw (1266) was less than that obtained for
both monoammonium salts (1588 for Example 24; 1618-for
Example 25). Other differences were that the extent of
foaming in Example 23-was at least ten times greater
than the extent of Foaming in the other examples. In
V1'O 96100744 219 319 8 PCT~S95108365
- 16 -
fact, the pan used for the reaction had overflowed
extensively during Example 23, whereas the contents of
the other two examples were contained in the reaction
pan. The extra equivalent of ammonia present may have '
caused this unusual expansion in Example 23.
Comparison of the heating curves for the wet
versus dry monoammonium maleate shows that the dry
starting material reached the final reaction temperature
earlierthan-the wet starting material. The Mw obtained
for both products was nearly the same, indicating that
for the reaction conditions and loading employed in
these Examples, wader content of the starting material
is not significant.
EXAMPLES 26-28: Layer Polymerization of
Monoammonium Maleate.
The purpose of his experiment was to
determine whether low temperature for long reaction
times would give high molecular weight__polysuccinimide
while minimizing thermal decomposition.- Results (Table
3 and Table-2, Example 6) indicate that Mw levels out at
two hours reaction time. The Mw's obtained are still
lower than experiments at higher temperatures for -
shorter times (Cf. Example 21). The method used was the
same as that in Examples 5-25, above.
W0 96100744 PCT/ITS9i/08365
2193198
- 17 -
TABLE
3
Cond itionsResults eactions les ~7
and of Polymerization for 26 28
R Examp
Starting Loading NominalTime
Mtl. Weightg reactantlOven in Weight Weight
from Loadedcmi Temp Oven Product Mwl Loss
Ex. Example (g) surface (C) (6) (g) Mw Mn (%)
26 3' 150.7 0.5 185 1.0 92.80 12762.6 38
27 3' 150.7 0.5 185 4.0 91.41 14633.0 39
28 3' 150.0 0.5 185 2.0 90.23 14813.2 40
' Hz0 content 13 wt.-%.
The heating curves for these Examples are
presented in-FIGURE 9.
EXAMPLES 29-31: Polymerization of Monoammoait=m
Maleate; Higla Loading.
The product of Example 3 was used as the
starting material for these examples. The water content
in the starting material was B.5% (w/w). The general
method used far Examples 29 and 30 was the same as that
used for Examples 5-25. The method used for Example 31
was the same except that in Example 31 a circular glass
dish having the dimensions-(12 cm ciia x 6 cm h) was used
in place of the rectangular aluminum pan.
WO 96100744 PCTIUS95108365
2193198
-18-
TABLE
4
Condit ions esults merizationReactions 30.
and of Poly for 31
R Examples
29.
Starting Loading NominalTime
Mtl. Weightg reactantlOven in Weight Weight
from Loadedcm' Temp Oven Product Mwl Loss
Ex. Example (g) surface (C) (h) (g) Mw Mn (%)
29 3' 499.311.7 - -3050.60 346.18387 2.6 30.7
30 3' 501.331.7 305 0.97 318.3211122.9 36.5
31 3' 206.18- - 1.8 305 0.60 129.9816042:9 37.0
-
' Hz0 content 8.5 wt: ~.
The heating curves for these examples are
shown in FIGURE 10.- The rate of temperature increase
for Example 31 was faster-than the rates for Examples 29
and 30. Accordingly, the Mw and percent weight loss for
Example 31 was greater than those for Example 29.
Reasons for this-are not clear, but the observed results
could be due to differences in packing volume of the
starting materials in the two different shaped
containers, thermal conductivity differences between the
two container materials, or to differences in container
wall height leading to differences in mixing of the
reaction intermediates and products.
EXAMPLE 32: Results from Polymerization
of Monoammonium Maleate is
a Stirred Reactor.
Monoammonium maleate (200.0 g), prepared using
the same method as in Example 3 but containing 9.2 %
(w/w) water, was loaded into a stainless steel reactor
(1200 ml volume) equipped with a mechanical stirrer.
The powdered starting material was stirred_in the.
reactor. The reactor was placed in an oil-bath at room
temperature. The temperature of the oil bath was
increased to 240°C over approximately a one hour period
WO 96/00744 PCTlt7595I08365
2193198
- 19 -
and kept at this temperature for one hour and then
cooled to 200°C for 20 minutes and then removed from the
oil bath and cooled to room temperature. The
temperature inside the reactor was also recorded.- The
heating curves and data are shown in FIGURE 11.
After about 0.75 to 1 hour into the heating
step described above (at an internal temperature of
about 160°C), the stirrer came to a complete stop. The
viscous reactor contents subsequently began to foam.
The viscous foam overflowed the top lid of the reactor.
At about 1.25 h into the heating, the contents stopped
foaming and formed a sticky mass. After the heating was
complete, the reactor contents were an non-homogeneous
mixture that occupied the entire volume of the reactor.
. The mixture contained regions that were sticky glasses
and other regions that were brittle foam-like solids.
The contents were crushed to a powder in a mortar,
weighed (132.5 g) and analyzed by size exclusion
chromatography as described in Examples 5-25: Mw 1158;
Mn 402; Mw/Mn 2.9.
This example demonstrates that it is not
practical to carry out the thermal polymerization in a
stirred reactor.
The foregoing examples and the accompanying
discussion are intended as illustrative and are not to
be taken as limiting of the present invention. Still
other variations within the spirit and scope of the
present invention are possible and will readily present
themselves to those skilled in.the art.
