U.S. patent application number 09/087257 was filed with the patent office on 2002-04-04 for wax crystal modifiers (law657).
Invention is credited to BERLUCHE, ENOCK, PATIL, ABHIMANYU ONKAR, VARMA-NAIR, MANIKA, ZUSHMA, STEPHEN.
Application Number | 20020040123 09/087257 |
Document ID | / |
Family ID | 22204075 |
Filed Date | 2002-04-04 |
United States Patent
Application |
20020040123 |
Kind Code |
A1 |
PATIL, ABHIMANYU ONKAR ; et
al. |
April 4, 2002 |
WAX CRYSTAL MODIFIERS (LAW657)
Abstract
The invention relates to a copolymer composition useful as wax
crystal modifiers and flow improvers. The compositions are
copolymers of a C.sub.6 to C.sub.250 straight-chain or branched
dialkyl fumarate and at least one compound selected from the group
consisting of carbon monoxide, C.sub.3 to C.sub.30 .alpha.-olefin,
ethylene, styrene, and vinyl acetate.
Inventors: |
PATIL, ABHIMANYU ONKAR;
(WESTFIELD, NJ) ; ZUSHMA, STEPHEN; (CLINTON,
NJ) ; BERLUCHE, ENOCK; (PHILLIPSBURG, NJ) ;
VARMA-NAIR, MANIKA; (WARREN, NJ) |
Correspondence
Address: |
EXXONMOBIL RESEARCH AND ENGINEERING COMPANY
Law Department
1545 Route 22 East
P.O. Box 900
Clinton Township, Annadale
NJ
08801-0900
US
|
Family ID: |
22204075 |
Appl. No.: |
09/087257 |
Filed: |
May 29, 1998 |
Current U.S.
Class: |
528/392 |
Current CPC
Class: |
C08G 67/02 20130101 |
Class at
Publication: |
528/392 |
International
Class: |
C08G 067/02 |
Claims
What is claimed is:
1. A copolymer of carbon monoxide and C.sub.6 to C.sub.250
straight-chain or branched dialkyl fumarate.
2. The composition of claim 1 wherein the alkyls range from C.sub.6
to C.sub.150.
3. The composition of claim 2 wherein the alkyls range from about
C.sub.8 to about C.sub.40.
4. The composition of claim 3 wherein the alkyls are
straight-chain.
5. A flow improver for use in an oleaginous fluid comprising one or
more copolymers of dialkyl fumarate wherein the alkyl is straight
chain or branched and ranges in size from C.sub.6 to C.sub.250 and
carbon monoxide.
6. The composition of claim 5 wherein the alkyls range from C.sub.6
to C.sub.150.
7. The composition of claim 6 wherein the alkyls range from about
C.sub.8 to about C.sub.40.
8. The composition of claim 7 wherein the alkyls are
straight-chain.
9. A wax crystal modifier for use in a crude oil having at least
one alkane species, comprising: a copolymer of dialkyl fumarate
having straight-chain or branched alkyls ranging in size from about
C.sub.6 to about C.sub.250 and at least one compound selected from
the group consisting of C.sub.3 to C.sub.30 alpha olefin, ethylene,
styrene, carbon monoxide, and vinyl acetate.
10. The composition of claim 9 wherein the alkyls range from
C.sub.6 to C.sub.150.
11. The composition of claim 10 wherein the alkyls range from about
C.sub.15 to about C.sub.40.
12. The composition of claim 11 wherein the alkyls are
straight-chain and have a molecular weight distribution
substantially the same as the crude oil's alkane species.
13. A method for improving the flow properties in an oleagenous
fluid comprising: adding to a major amount of the oleagenous fluid
a minor amount of at least one copolymer of dialkylfumarate having
C.sub.6 to C.sub.250 straight chain or branched alkyls and at least
one compound selected from the group consisting of C.sub.3 to
C.sub.30 alpha olefin, ethylene, styrene, and carbon monoxide,
provided that when the oleagenous fluid is a lubricating oil or a
distillate oil that the compound is carbon monoxide.
14. A method for forming a copolymer comprising: dissolving a
C.sub.6 to C.sub.250 straight-chain dialkyl fumarate in a solvent
selected from the group consisting of hexane, benzene, cyclohexane,
chloroform, xylene, oil, and heptane; combining the dissolved
dialkyl fumarate and an initiator selected from the group
consisting of t-butyl peroxypivalate, benzoyl peroxide, t-butylper
benzoate, and t-butyl peroxide in a reactor; sealing the reactor
and then purging the reactor with purified nitrogen; pressurizing
the reactor with one or more compounds selected from the group
consisting of carbon monoxide and ethylene to a pressure ranging
from about 100 to about 3000 psig; and heating the reactor to a
temperature ranging from about 40.degree. C. to about 200.degree.
C. for a time ranging from about 1 hour to about 48 hours in order
to form the copolymer.
15. The method of claim 14 wherein the pressure ranges from about
500 psig to about 1200 psig, the temperature ranges from about
50.degree. C. to about 100.degree. C., the solvent in hexane, and
the initiator is t-butyl peroxypivilate.
16. The method of claim 15 including cooling and depressurizing the
reactor and then recovering the copolymer from the solvent.
17. A method for forming a copolymer comprising: combining under
free radical polymerization conditions a C.sub.6 to C.sub.250
straight-chain dialkyl fumarate in a solvent selected from the
group consisting of hexane, benzene, cyclohexane, chloroform,
xylene, oil, and heptane; at least one compound selected from the
group consisting of ethylene and carbon monoxide; and an initiator
selected from the group consisting of t-butyl peroxypivalate,
benzoyl peroxide, t-butyl perbenzoate, and t-butyl peroxide, for a
time, temperature, and pressure sufficient to form the
copolymer.
18. The method of claim 17 wherein the pressure ranges from about
500 psig to about 1200 psig, the temperature ranges from about
50.degree. C. to about 100.degree. C., the solvent in hexane, and
the initiator is t-butyl peroxypivilate.
19. The method of claim 18 including cooling and depressurizing the
reactor and then recovering the copolymer from the solvent.
20. A method for improving the flow properties in an oleagenous
fluid having at least one alkane species comprising: determining a
molecular weight distribution of the alkane species in the
oleagenous fluid and then adding to a major amount of the
oleagenous fluid a minor amount of at least one copolymer of
dialkylfumarate having straight-chain or branched alkyls with
substantially the same molecular weight distribution as the
oleagenous fluids alkanes species and at least one compound
selected from the group consisting of C.sub.3 to C.sub.30 alpha
olefin, ethylene, styrene, and carbon monoxide.
Description
FIELD OF THE INVENTION
[0001] The invention relates to wax crystal modifiers useful in
improving the flow characteristics of lube oils and waxy
crudes.
BACKGROUND
[0002] Many oils, especially crude oils, contain straight chain and
branched alkanes that crystallize as their temperature is lowered.
Alkane (wax) crystallization in these oils results in increased
viscosity which leads to problems such as pipelining difficulties
in crudes. The temperature at which wax begins to crystallize in an
oil is called the wax appearance temperature (WAT) of the oil.
Polymeric and copolymeric compounds can be combined with an oil in
order to reduce an oil's WAT. Such additives, known as wax crystal
modifiers, can be used as flow improvers in lubricating oils.
[0003] Lubricating oils and crude oils have quite different
compositions. For example, crude oils contain inorganics, resins,
and asphaltenes that are not present in lubricating oils beyond
trace levels. Crude oils also contain hydro-carbons having a wider
range of molecular weights. These factors contribute to a higher
WAT than in lubricating oils. Crude oil WATs can range from about
-15.degree. C. to about 30.degree. C., compared to a range of about
-25.degree. C. to about -5.degree. C. for lubricating oils.
[0004] Dialkyl fumarate-vinyl acetate (DAF-VA) copolymers are used
as lubricating oil flow improvers. These copolymers may be formed
by the free radical polymerization of vinyl acetate and DAF esters
having alkyls ranging in size from about 10 to about 18 carbon
atoms. Such copolymers are effective lubricating oil flow improvers
at temperatures ranging from about -25.degree. C. to about
-5.degree. C. Such flow improvers are not expected to be effective
for crude oils because crude oil WATs are generally outside this
temperature range.
[0005] There remains a need for polymers and copolymers useful for
improving the flow properties of oils, and especially polymers and
copolymers capable of improving the flow properties and
pipelinability of crude oils.
SUMMARY OF THE INVENTION
[0006] In one embodiment, the invention is a copolymer of carbon
monoxide and C.sub.6 to C.sub.250 straight-chain or branched
dialkyl fumarate.
[0007] In another embodiment, the invention is a flow improver for
use in an oleaginous fluid comprising one or more copolymers of
dialkyl fumarate wherein the alkyl is straight chain or branched
and ranges in size from C.sub.6 to C.sub.250 and carbon
monoxide.
[0008] In another embodiment, the invention is a crude oil wax
crystal modifier comprising a copolymer of dialkyl fumarate having
straight chain or branched alkyls ranging in size from about
C.sub.6 to about C.sub.250 and at least one compound selected from
the group consisting of C.sub.3 to C.sub.30 alpha olefin, ethylene,
styrene, carbon monoxide, and vinyl acetate.
[0009] In another embodiment, the invention is a method for
improving the flow properties in an oleagenous fluid comprising:
adding to a major amount of the oleagenous fluid a minor amount of
at least one copolymer of dialkyl-fumarate having C.sub.6 to
C.sub.250 straight chain or branched alkyls and at least one
compound selected from the group consisting of C.sub.3 to C.sub.30
alpha olefin, ethylene, styrene, and carbon monoxide, provided that
when the oleagenous fluid is a lubricating oil or a distillate oil
that the compound is carbon monoxide.
[0010] In another embodiment, the invention is a method for forming
a copolymer comprising:
[0011] dissolving a C.sub.6 to C.sub.250 straight-chain dialkyl
fumarate in a solvent selected from the group consisting of hexane,
benzene, cyclohexane, chloroform, xylene, oil, and heptane;
[0012] combining the dissolved dialkyl fumarate and an initiator
selected from the group consisting of t-butyl peroxypivalate,
benzoyl peroxide, t-butylper benzoate, and t-butyl peroxide in a
reactor;
[0013] sealing the reactor and then purging the reactor with
purified nitrogen;
[0014] pressurizing the reactor with at least one compound selected
from the group consisting of carbon monoxide and ethylene to a
pressure ranging from about 100 to about 3000 psig; and
[0015] heating the reactor to a temperature ranging from about
40.degree. C. to about 200.degree. C. for a time ranging from about
1 hour to about 48 hours in order to form the copolymer.
[0016] In another embodiment, the invention is a method for forming
a copolymer comprising:
[0017] combining under free radical polymerization conditions a
C.sub.6 to C.sub.250 straight-chain dialkyl fumarate in a solvent
selected from the group consisting of hexane, benzene, cyclohexane,
chloroform, xylene, oil, and heptane; at least one compound
selected from the group consisting of ethylene and carbon monoxide;
and an initiator selected from the group consisting of t-butyl
peroxypivalate, benzoyl peroxide, t-butylper benzoate, and t-butyl
peroxide, for a time, temperature, and pressure sufficient to form
the copolymer.
[0018] In another embodiment, the invention is a method for
improving the flow properties in an oleagenous fluid having at
least one alkane species comprising:
[0019] determining a molecular weight distribution of the alkane
species in the oleagenous fluid and then
[0020] adding to a major amount of the oleagenous fluid a minor
amount of at least one copolymer of dialkylfumarate having straight
chain or branched alkyls having substantially the same molecular
weight distribution and at least one compound selected from the
group consisting of C.sub.3 to C.sub.30 alpha olefin, ethylene,
styrene, and carbon monoxide.
DETAILED DESCRIPTION OF THE INVENTION
[0021] The invention is based on the discovery that
dialkylfumarate-containing copolymers having straight chain or
branched alkyls ranging in size from about C.sub.6 to about
C.sub.250 are effective flow improvers in oleaginous fluids such as
fuel oils, lubricating oils, and crude oils. The invention is also
based on the discovery that dialkylfumarate can be copolymerized
with carbon monoxide.
[0022] Copolymers of the present invention having the formula:
1
[0023] wherein B is formed from compounds selected from the group
consisting of carbon monoxide, vinyl acetate, styrene, ethylene,
and C.sub.3 to C.sub.30 alpha olefin and wherein R is branched or
straight chain alkyl ranging from C.sub.6 to C.sub.250 are prepared
as follows.
[0024] Dialkylfumarate esters having alkyls ranging up to C.sub.250
are prepared by diesterification of fumaric acid with aliphatic
alcohols in the presence of a p-toluene sulfonic acid catalyst.
Alternatively, the esters can be prepared from fumaryl chloride and
alkyl alcohols using an amine catalyst.
[0025] Comonomer B is formed from at least one compound selected
from the group consisting of vinyl acetate, styrene, C.sub.3 to
C.sub.30 .alpha.-olefin, ethylene, and carbon monoxide. The term
copolymer is thus used in accordance with its more general meaning
where the polymer comprises two or more different monomers.
[0026] R represents independently selected straight chain or
branched alkyl groups of from about C.sub.6 to about C.sub.250
carbon atoms. Preferred alkyls range from about C.sub.8 to about
C.sub.40.
[0027] The copolymers of this invention can be synthesized using
free-radical polymerization. In the case of copolymers of dialkyl
fumarate with monomers like vinyl acetate, styrene or C.sub.3 to
C.sub.30 .alpha.-olefins, polymerization can be carried out in a
standard glass reactor. Typically, any inhibitors present in the
monomers are removed via an inhibitor remover column. The purified
monomers are then placed in tubes with the DAF ester monomers. The
tubes are capped with septa and flushed with nitrogen for one to
four hours before polymerization. The composition of monomers can
be varied from about 5:95 to about 95:5 mole percent.
[0028] The reactions can be carried out in a solvent or neat. When
a solvent is used, the solvent should be nonreactive or
noninterfering in free radical polymerization. Such solvents
include benzene, cyclohexane, hexane, heptane, etc. Solvents like
xylene or oil can also be used. The solvent may be flushed with
argon or nitrogen and then added to the monomers.
[0029] The polymerization reactions can be carried out from 40 to
100.degree. C. depending on reactivity of monomers, half-life of
the initiator used, or the boiling point of the solvent. The
reactions are carried out under inert atmosphere. The solvents are
brought to the reaction temperatures, and the initiator (dissolved
in the appropriate solvents) is added to the solution. Typical free
radical initiators includes dialkyl peroxides such as
ditertiary-butyl peroxide,
2,5-dimethyl-2,5-di-tertiary-butylperoxyhexane, di-cumyl peroxide;
alkyl peroxides such as benzoyl peroxide; peroxy esters such as
tertiary-butyl peroxypivalate, tertiary-butyl perbenzoate; and also
compounds such as azo-bis-isobutyronitrile. A free radical
initiator with an appropriate half life at reaction temperature of
from about 60.degree. C. to about 140.degree. C. can be used. For
the reactions done neat (without solvent), both monomers and
initiator are loaded together, flushed with nitrogen, and then
brought to reaction temperature. The components are stirred for a
time sufficient to form a uniform mixture.
[0030] Reaction time ranges from about 1 hour to about 48 hours.
The resulting polymer is isolated by precipitating the polymer in
non-solvent (solvent in which polymer is not soluble). The product
is then dried in vacuum oven.
[0031] When forming the compounds of the present invention from
monomers that are gases at ambient temperature and pressure, such
as ethylene and carbon monoxide, the reactions are generally
carried out in high pressure reactors such as autoclave reactors.
In such copolymerizations, the reactor is initially charged with
monomers like dialkyl fumarate dissolved in a solvent such as
hexane, and initiator is added. Typical initiators include t-butyl
peroxypivalate, benzoyl peroxide, t-butylper benzoate, t-butyl
peroxide. The reactor is sealed and purged with purified nitrogen.
The reactor is then pressurized with carbon monoxide and/or
ethylene monomer to appropriate pressure. The pressure can range
from about 100 to about 3,000 psig. The preferred polymerization
pressure ranges from about 500 to about 1,200 psig. Reaction
temperature can range from about 40.degree. C. to about 200.degree.
C., depending on solvent and the initiator half-life. The pressure
of the reaction can be maintained for about one hour to about 48
hours depending on monomer reactivity, solvent, and the initiator
half-life. The reactor is allowed to cool to room temperature and
is then depressurized. A rotary evaporator is used to remove the
solvent and obtain the product.
[0032] The products are generally characterized by standard
techniques such as FTIR, NMR, and GPC.
[0033] According to the present invention, wax crystal modifiers
are added to an oleaginous fluid such as oil in a concentration
ranging from about 10 to about 50,000 ppm based on the weight of
the oil. The preferred concentration is about 500 ppm. Non-limiting
examples of oleaginous fluids containing paraffinic (alkane)
species that benefit from the addition of the compounds of the
invention include crude oils, i.e., oils as obtained from drilling
and before refining or separating, fuel oils such as middle
distillate fuel oil, and oils of lubricating viscosity
("lubricating oils").
[0034] It is believed that copolymer flow improvers of this
invention when present in an effective amount are capable of
inhibiting the nucleation and growth of wax crystals in oleaginous
fluids such as oils. While not wishing to be bound by any theory,
it is believed that the presence of an effective amount of
copolymer results in a lowering the oil's wax appearance
temperature because the copolymer molecules are sufficiently
similar to the paraffinic crude species to incorporate themselves
into growing wax crystals. Once incorporated, it is believed that
the polymeric nature of the flow improver, i.e., its "branchiness"
and high molecular weight, prevent the further addition of the
crude's paraffinic species to the crystal. The presence of the
copolymer in the growing wax crystal is also believed to alter the
crystals' morphology by inhibiting growth that naturally tends
towards undesirable large flat platelets. Such platelets are
believed to result from the interlocking, intergrowth, and
agglomeration of nucleated wax crystallites. Such changes in
crystal shape resulting from copolymer incorporation greatly
diminish the wax crystals' ability to interlock, intergrow, and
agglomerate.
[0035] In the practice of the invention, it is desirable to first
determine the molecular weight distribution of the paraffinic
species present in the oil. It is believed that the compounds of
the present invention are most effective when the molecular weight
distribution of the alkyls present in the fumaric species of the
copolymer is approximately the same as the molecular weight
distribution of the oil's paraffinic species.
[0036] While the compounds of the present invention are useful in
all oleaginous fluids containing paraffinic species, the preferred
compound will depend on the type of fluid used.
[0037] For lubricating oils, for example, flow improvement is
needed at temperatures much lower than are ordinarily required for
crude oil. Consequently, copolymers with alkyls in the fumarate
species ranging from about C.sub.12 to about C.sub.14 and molecular
weights ranging from about 2000 to about 100,000 are preferred. In
crude oils, compounds of reduced solubility are required, and the
preferred compounds contain alkyls ranging from about C.sub.15 to
about C.sub.40 and molecular weights ranging from about 2,000 to
about 50,000. For distillate oils, preferred copolymers contain
alkyls ranging from about C.sub.10 to about C.sub.22 and have
molecular weights ranging from about 2,000 to about 20,000.
EXAMPLES
[0038] The invention is further described in the following
non-limiting examples.
[0039] I. Synthesis of Dialkyl Fumarate Ester Monomers
Example 1.
[0040] Monomer Synthesis from Fumaric Acid and 1-eicosanol
[0041] Into the reaction flask (equipped with a condenser and a
Dean-Stark trap apparatus to remove the reaction water as it
formed), were added 2.8 g (FW 116.07, 0.01875 moles) of fumaric
acid, 11.2 g (0.0375 moles) of 1-eicosanol (FW 298.56), 0.3567 g
(0.00188 mole) of .rho.-toluenesulfonic acid monohydrate, and 50 mL
to toluene. The mixture was heated at 130.degree. C. for 18 hours
under nitrogen. The reaction was then cooled to room temperature
and filtered and solvent toluene was removed by a rotary evaporator
to obtain the product (mp 71-73.degree. C.). The C.sub.20 fumarate
ester product was characterized by IR and NMR spectroscopy. The IR
spectrum of the product was recorded as the melted solid film in
NaCl plates. The spectrum showed an ester peak at 1728 cm.sup.-1
and a double bond absorption peak at 1647 cm.sup.-1. .sup.13C NMR
of the product showed the double bond absorption peak at 134.0 ppm
(trans --HC.dbd.CH--, carbon) and the carbonyl ester peak at 165
ppm. The NMR spectrum also showed an absorption peak at 66 ppm due
to a methylene next to ester functionality (--C(O)O--CH.sub.2--).
The absorption peaks in the aliphatic region are typical of the
straight chain alkyl groups.
Example 2.
[0042] Monomer Synthesis from Fumaric Acid and 1-docosanol
[0043] Using the procedure of Example 1, a C.sub.22 fumarate ester
product was formed. A .sup.13C NMR spectrum of the product showed a
double bond absorption peak at 134.0 ppm (trans --HC.dbd.CH--,
carbon) and a carbonyl ester peak at 165 ppm. There was also an
absorption peak at 66 ppm due to a methylene next to ester
functionality (--C(O)O--CH.sub.2--).
Example 3.
[0044] Monomer Formation from Fumaryl Chloride and Polyethylene
Monoalcohol
[0045] Into a round bottom flask, 22.6 g (0.032 mole) of
polyethylene monoalcohol (mw 700) available from Aldrich, Inc.,
Milwaukee, Wis., was placed with 300 mL toluene. The mixture was
heated to 80.degree. C. under nitrogen, and then 30 mL of
triethylamine was added. 2.6 g (0.017 mole) of fumaryl chloride
diluted with 25 mL of toluene was then slowly added over a period
of 1 hour. After addition, the mixture was heated at 80.degree. C.
for 4 hours under nitrogen. The reaction mixture was then poured
into 1500 mL of methanol containing 90 mL of HCl. The precipitated
product was then filtered, washed with methanol, and dried in
vacuum at 75.degree. C. for 12 hours to obtain 23.1 g of the
fumarate ester product.
[0046] An IR spectrum of the product showed an absorption peak due
to ester carbonyl at 1724 cm.sup.-1 and a small double bond peak at
1647 cm.sup.-1. The spectrum also showed two sharp peaks at 729 and
719 cm.sup.-1 similar to that of polyethylene. .sup.13C NMR of the
product showed a double bond absorption peak at 134.0 ppm
(--HC.dbd.CH--, carbon) and a carbonyl ester peak at 165 ppm. There
was also an absorption peak at 66 ppm due to a methylene next to
the ester functionality (--C(O)O--CH.sub.2--). This peak was
shifted with respect to the peak for methylene next to the --OH in
PE--OH (HO--CH.sub.2--) at 63 ppm.
Example 4.
[0047] Monomer Formation from Fumaric Acid and
Polyethylene-butylene Monoalcohol
[0048] 0.15 g (0.00125 mole) of fumaric acid, 8.3 g (0.00125 mole)
of polyethylene butylene monoalcohol(M.sub.n.dbd.3317), and 0.0238
g (0.00125 moles) of p-toluene sulfonic acid monohydrate were
placed into a reaction flask and heated to 100.degree. C. for 20
hours under nitrogen. The reaction product was then poured into
water, separated, and washed with acetone. The residue was dried
under vacuum.
[0049] An IR spectrum of the fumarate ester product showed an
absorption peak due to the ester carbonyl at 1724 cm.sup.-1 and a
small double bond peak at 1647 cm.sup.-1. The proton NMR spectrum
showed a double bond absorption at 6.9 ppm (.dbd.CH, proton), and a
--C(O)OCH.sub.2--absorptio- n peak at 4.2 ppm. The starting
alcohol, EB--OH, showed a --CH.sub.2OH peak at 3.7 ppm. Integration
of --CH.sub.2-- from EB--OH and --CH.sub.2-- from --C(O)OCH.sub.2--
absorption peak showed that there was 34% unreacted EB in the
product. Washing the product with water ensured that the product
contained no unreacted fumaric acid.
[0050] II. Synthesis of Dialkylfumarate-Containing Copolymers by
Free Radical Polymerization
[0051] Hydroquinone inhibitor was removed from the vinyl acetate
via through an inhibitor remover column. The purified vinyl acetate
was placed in tubes with DAF ester monomers. The tubes were capped
with septa and flushed with nitrogen for one hour. The solvent was
flushed with nitrogen and added to the tubes containing the
monomers. The solutions were brought to their reaction
temperatures, and the initiator (dissolved in the appropriate
solvents) was added to each monomer solution. For the runs done
neat (without solvent), both monomers and initiator were loaded
together, flushed with nitrogen, and then brought to reaction
temperature. The mixtures were stirred overnight. After 24 hours,
the polymer solutions were precipitated in methanol, vacuum dried,
and then characterized by NMR and GPC. The results are summarized
in Table 1. In the table, mole ratios in wt% are monomer feed
ratios, and mole ratios by NMR are product mole ratios.
1TABLE 1 Example Mole Reaction Reaction GPC Number Monomers Ratio
Solvent Initiator Temperature Peak MW GPC M.sub.n GPC M.sub.w
M.sub.w/M.sub.n 5 C.sub.20 DAF/VA 40/60 wt % Benzene 3% AIBN
65.degree. C. 21,700 11,600 24,750 2.1 34/66 (NMR) 6 C.sub.22
DAF/VA 40/60 wt % Benzene 3% AIBN 65.degree. C. 15,700 8,100 16,800
2.1 38/62 (NMR) 7 C.sub.20 DAF/VA 57/43 wt % Neat 3% AIBN
75.degree. C. 28,400 18,000 44,200 2.5 27/73 (NMR) 8 C.sub.22
DAF/VA 57/43 wt % Neat 3% AIBN 75.degree. C. 27,600 18,600 37,000
2.0 26/74 (NMR)
[0052] III. Synthesis of Dialkylfumarate-Alpha Olefin and
Dialkyfumarate-Styrene Copolymers
[0053] Polymerization procedures as set forth for examples 5
through 8 were used to synthesize copolymers of dialkylfumarate and
styrene and alpha olefin. The reaction conditions and analysis
results are set forth in Table 2. Mole ratio conventions are as set
forth in Table 1.
2TABLE 2 Example Mole Reaction Reaction GPC Number Monomers Ratio
Solvent Initiator Temperature Peak MW GPC M.sub.n GPC M.sub.w
M.sub.w/M.sub.n 9 DAF-II/C.sub.16 50/50 Chloroform 3% AIBN
65.degree. C. 2,727 1,080 2,556 2.4 Alpha Olefin 59.4/40.6 (NMR) 10
DAF-II/Styrene 50/50 Chloroform 3% AIBN 65.degree. C. 21,492 10,589
20,731 1.96 19.7/80.3 (NMR)
[0054] IV. Synthesis of Dialkyfumarate-ethylene Copolymers
Example 11
[0055] A 300 mL autoclave engineer's reactor was charged with 10 g
of dialkyl fumarate wherein the alkyls have an average of
approximately 13 carbon atoms (C.sub.13DAF), 150 mL pure n-hexane,
and 0.502 g of a 75% solution of t-butyl peroxypivalate in mineral
spirits. [t-Butyl peroxypivalate has a 10 hour half-life at
55.degree. C. in a 0.2 M benzene solution) (Swern, Organic
Peroxides, John Wiley and sons, 1970, Vol. 1, pp. 82, 87)]. The
mixture was dissolved with stirring. The reactor was sealed and
purged with purified nitrogen. The reactor was then pressurized
with ethylene to 700 psig. The temperature was raised to 66.degree.
C. while stirring, and the pressure was maintained for 24 hours.
The reactor was allowed to cool to room temperature, and was then
depressurized. The hexane was removed with a rotary evaporator,
leaving 20 g of the product.
[0056] IR spectra of the product suggested no unreacted DAF
monomer. The IR spectra of the product indicated the presence of
carbonyl at 1738 cm.sup.-1 and two characteristic polyethylene
peaks at 729 and 719 cm.sup.-1. .sup.13C NMR of this product was
recorded in CDCl.sub.3 using Chromium (III) acetylacetonate
(Cr(acac).sub.3). .sup.13C NMR of this product showed only an ester
carbonyl absorption peak at 172 ppm. Integration of carbonyl peaks
suggested 2.6% carbonyl carbons.
[0057] V. Synthesis of Dialkylfumarate-Carbon Monoxide Copolymer
and Dialkylfumarate-Carbon Monoxide Ethylene Terpolymer
Example 12
[0058] Dialkylfumarate-Carbon Monoxide Copolymers
[0059] A 300 mL autoclave engineer's reactor was charged with 5 g
of dialkyl fumarate wherein the alkyls have an average of
approximately 13 carbon atoms (C.sub.13DAF) dissolved in 150 ml
n-hexane and 0.507 grams of a 75% solution of t-butyl
peroxypivilate in mineral spirits The reactor was sealed and purged
with purified nitrogen. The reactor was then pressurized with
carbon monoxide to 700 psig. The temperature was raised to
66.degree. C. while stirring and the pressure was maintained for 24
hours. The reactor was allowed to cool to room temperature and was
then depressurized. Then hexane was removed on rotary evaporator
leaving 4.5 grams of the product.
[0060] IR of the product showed a ester carbonyl peak at 1738
cm.sup.-1 and disappearance of double bond peak in the DAF monomer
at 1649 cm.sup.-1. .sup.13C NMR of this product was recorded in
CDCl.sub.3 using Cr(acac).sub.3 as a relaxation agent, allowing
quantification of the spectrum. .sup.13C NMR of this product showed
complete disappearance of the double bond peak at 134 ppm and the
monomer carbonyl peak at 165 ppm. The product showed two types of
carbonyls (multiples peaks around 206 ppm and 172 ppm). The
relative integration of the carbonyls in the product suggests that
there is 10% CO incorporation from carbon monoxide in the
copolymer.
[0061] GPC of the product was recorded in THF using polystyrene
standards. GPC of the product showed that polymer had a Mn of 1547
and Mw of 2228.
Example 13.
[0062] A 300 ml autoclave engineer's reactor was charged with 2.5 g
of didocosanyl fumarate (C.sub.22 fumarate ester) dissolved in 150
mL n-hexane and 0.502 g of a 75% solution of t-butyl peroxypivalate
in mineral spirits The reactor was sealed and purged with purified
nitrogen. The reactor was then pressurized with carbon monoxide to
700 psig. The temperature was raised to 66.degree. C. while
stirring and the pressure was maintained for 24 hours. The reactor
was allowed to cool to room temperature and was then depressurized.
Then hexane was removed on rotary evaporator leaving 4.5 g of the
product. An IR of the product showed an ester carbonyl peak at 1740
cm.sup.-1 and disappearance of the double bond peak in the DAF
monomer at 1649 cm.sup.-1. .sup.13C NMR of this product was
recorded in CDCl.sub.3 using Cr(acac).sub.3 as a relaxation agent,
allowing quantification of the spectrum. .sup.13C NMR of this
product showed complete disappearance of the double bond peak at
134 ppm and monomer carbonyl peak at 165 ppm. The product showed
two types of carbonyls peaks around 206 ppm and 172 ppm. GPC of the
product was recorded in THF using polystyrene standards. GPC of the
product showed that polymer had a Mw of 2840.
Example 14
[0063] Dialkylfumarate-Carbon Monoxide-Ethylene Terpolymers
[0064] A 300 ml autoclave engineer's reactor was charged with 10 g
of dialkyl fumarate wherein the alkyls have an average of
approximately 13 carbon atoms (C.sub.13DAF) dissolved in 150 ml
n-hexane and 0.504 grams of a 75% solution of t-butyl
peroxypivalate in mineral spirits The reactor was sealed and purged
with purified nitrogen. The reactor was then pressurized with
ethylene/carbon monoxide (90:10) mixture to 700 psig. The
temperature was raised to 66.degree. C. while stirring and the
pressure was maintained for 24 hours. The reactor was allowed to
cool to room temperature and was then depressurized. Then hexane
was removed on rotary evaporator leaving 13.9 grams of the
product.
[0065] IR spectra of the product showed a carbonyl ester peak at
1724 cm.sup.-1 and polyethylene peaks at 723 cm.sup.-1. IR spectra
of the product also showed absence of double bond peak due to
unreacted DAF monomer. .sup.13C NMR of this product was recorded in
CDCl.sub.13 using Cr(acac).sub.3 as a relaxation agent, allowing
quantification of the spectrum. .sup.13C NMR of this product
suggested that there were two types of carbonyls, namely ester and
ketone in the terpolymer. The measurements revealed the presence of
multiple peaks around 210 ppm resulting from ketones and an
absorption peak at 173 ppm resulting from an ester. NMR spectra
also showed that there were no absorption peaks due to unreacted
DAF monomer ester (165 ppm) and unreacted double bond (134 ppm).
GPC of the product was recorded in THF using polystyrene standards.
GPC showed multiple peaks, with peaks at 661184, 15599 and 1375
g/mole. The product was soluble in hexane and THF. From this
observation, we concluded that the product could not be either high
molecular weight PE or ECO copolymer because both of these
materials are insoluble in hexane. Varying the amount of ethylene
monomer in the reaction can be used to control the molecular
weight, and thus, the crystallinity and solubility of the
polymers.
[0066] VI. Performance of Dialkylfumarate--Containing Copolymers as
Wax Crystal Modifiers in Crude Oil
[0067] The results are summarized in Table 3.
[0068] The performance of the products from examples 5, 7, 10, 11,
12, 13, and 14 were evaluated using differential scanning
calorimetry (DSC) with liquid nitrogen cooling. Measurements were
conducted over a temperature ranging from about -140.degree. C. to
about 100.degree. C. on both heating and cooling at a rate of
10.degree. C./minute. Nitrogen was used as a purge gas at 50
cm.sup.3/minute. All solutions were warmed to about 60.degree. C.
before sampling, and care was taken to ensure that the additive
compounds were soluble in the oils. Hermetically sealed aluminum
pans were used for all measurements to prevent any loss of low
volatility components.
[0069] Wax Appearance Temperature (WAT) is a measure of the
thermodynamic barrier for the formation of a stable nucleus for
further crystal growth. The WAT is the temperature at which stable
wax crystals first begin to appear. For wax crystallization to
occur, supercooling is required to overcome the free energy barrier
to nucleation. A lower WAT is desirable in an oil because it is
indicative of a larger thermodynamic barrier to further wax crystal
growth. Additive compounds that inhibit wax crystal nucleation
increase the free energy barrier and decrease the WAT. The wax
appearance temperatures (WAT) of Alaskan North Slope Crude with and
without the experimental additives were determined by cooling the
crude at 10.degree. C./minute. The WAT for the untreated Alaskan
North Slope Crude was 14.35.degree. C. With the additive of Example
5, the WAT was 13.71.degree. C. at 500 ppm additive concentration;
with the additive of Example 11 at 500 ppm additive concentration,
it was 11.00.degree. C. The effect of change in additive
concentration of Example 5 was studied using DSC. The results are
summarized in Tables 3 and 4.
[0070] The additive in Example 5 was also evaluated by a pour point
test. At 0.5 wt % concentration, the pour point of the Alaskan
North Slope Crude was decreased by 7.degree. C. These results
indicate that these additives are active as wax crystal
modifiers.
3 TABLE 3 Sample Wax Appearance Temperature, .degree. C. Untreated
Crude 14.35 500 ppm of Example 5 13.45 500 ppm of Example 11 11.00
500 ppm of Example 12 13.30 500 ppm of Example 14 13.05 500 ppm of
Example 7 13.35 500 ppm of Example 10 13.35 500 ppm of Example 131
11.60
[0071]
4 TABLE 4 Amount of Additive #5 in Crude (PPM) Wax Appearance
Temperature, .degree. C. 0 14.35 512 13.71 250 11.14 5048 8.30
* * * * *