U.S. patent application number 16/224934 was filed with the patent office on 2019-07-04 for phase change materials for enhanced heat transfer fluid performance.
The applicant listed for this patent is ExxonMobil Research and Engineering Company. Invention is credited to Angela M. BRUNEAU, Aditya JAISHANKAR, Halou OUMAR-MAHAMAT, Abhimanyu O. PATIL, Martin N. WEBSTER.
Application Number | 20190203138 16/224934 |
Document ID | / |
Family ID | 67058028 |
Filed Date | 2019-07-04 |
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United States Patent
Application |
20190203138 |
Kind Code |
A1 |
OUMAR-MAHAMAT; Halou ; et
al. |
July 4, 2019 |
PHASE CHANGE MATERIALS FOR ENHANCED HEAT TRANSFER FLUID
PERFORMANCE
Abstract
A composition for enhanced heat transfer fluid performance. The
composition includes at least one base heat transfer fluid. The at
least one base heat transfer fluid undergoes one or more phase
changes in a heat transfer process. The heat transfer process
includes a heated zone and/or a cooled zone. The one or more phase
changes increase heat removal from the heated zone and/or increase
heat rejection in the cooled zone, as compared to heat removal from
a heated zone and/or heat rejection in a cooled zone of a heat
transfer process having a base heat transfer fluid that does not
undergo one or more phase changes. The base heat transfer fluids
can exhibit liquid crystal behavior (e.g., heat transfer fluids
having nematic, smectic or discotic liquid crystals). A method for
conducting heat transfer in a heating and/or cooling system using
the compositions comprising the base heat transfer fluids.
Inventors: |
OUMAR-MAHAMAT; Halou;
(Mullica Hill, NJ) ; BRUNEAU; Angela M.;
(Berkeley, CA) ; WEBSTER; Martin N.; (Pennington,
NJ) ; PATIL; Abhimanyu O.; (Westfield, NJ) ;
JAISHANKAR; Aditya; (Clinton, NJ) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ExxonMobil Research and Engineering Company |
Annandale |
NJ |
US |
|
|
Family ID: |
67058028 |
Appl. No.: |
16/224934 |
Filed: |
December 19, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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62611057 |
Dec 28, 2017 |
|
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62611072 |
Dec 28, 2017 |
|
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62611081 |
Dec 28, 2017 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C09K 19/00 20130101;
C10M 2219/101 20130101; C10M 119/12 20130101; C09K 19/3491
20130101; C09K 2019/2035 20130101; C10M 105/06 20130101; C10N
2030/02 20130101; C10M 105/32 20130101; C10M 2205/046 20130101;
C10M 2203/065 20130101; C10N 2040/06 20130101; C10M 105/72
20130101; C09K 19/062 20130101; C10N 2020/02 20130101; C10M
2205/0213 20130101; C10M 2207/2845 20130101; C10N 2030/06 20130101;
C10M 2219/102 20130101; C10M 2207/284 20130101; C10M 119/02
20130101; C10M 2219/086 20130101; C09K 2019/3009 20130101; C10N
2030/10 20130101; C10N 2040/30 20130101; C10M 133/24 20130101; C10M
169/044 20130101; C10M 105/34 20130101; C10N 2020/079 20200501;
C10N 2040/25 20130101; C10M 2205/0285 20130101; C09K 5/10 20130101;
C10M 2215/16 20130101; C09K 2019/122 20130101; C10M 129/70
20130101; C10M 2209/084 20130101; C10M 105/56 20130101 |
International
Class: |
C10M 105/56 20060101
C10M105/56; C10M 105/06 20060101 C10M105/06; C10M 119/02 20060101
C10M119/02; C10M 105/34 20060101 C10M105/34; C10M 105/72 20060101
C10M105/72 |
Claims
1. A composition for enhanced heat transfer fluid performance, said
composition comprising at least one base heat transfer fluid,
wherein the at least one base heat transfer fluid undergoes one or
more phase changes in a heat transfer process, wherein the heat
transfer process comprises a heated zone and/or a cooled zone,
wherein the one or more phase changes increase heat removal from
the heated zone and/or increase heat rejection in the cooled zone,
as compared to heat removal from a heated zone and/or heat
rejection in a cooled zone of a heat transfer process having a base
heat transfer fluid that does not undergo one or more phase
changes.
2. The composition of claim 1 wherein the at least one base heat
transfer fluid comprises liquid crystals.
3. The composition of claim 1 wherein the at least one base heat
transfer fluid comprises one or more nematic, smectic or discotic
liquid crystals.
4. The composition of claim 2 wherein the one or more liquid
crystals are represented by the formula:
R1-(A).sub.m-Y--(B).sub.n--R2 wherein R1 and R2 are the same or
different and are a substituted or unsubstituted, alkyl group or
alkoxy group having from about 2 to about 24 carbon atoms; A and B
are the same or different and are a cycloaliphatic group or
aromatic group, provided at least one of A and B is an aromatic
group; Y is a covalent bond, --CH2-CH2-, --CH.dbd.CH--, --COO--,
--CO--, --CSO--, --CSS--, --CS--, --O--, --S--, --SO--, --SO2-, or
--CH2O--; and m and n are independently 0, 1, 2 or 3.
5. The composition of claim 2 wherein the one or more liquid
crystals are represented by the formula: ##STR00010## or
6. The composition of claim 2 wherein the one or more liquid
crystals are selected from the group consisting of
4'-n-octyl-4-cyano-biphenyl,
4-(trans-4-heptylcyclohexyl)-pentylbenzene,
4-(trans-4-heptylcyclohexyl)-propylbenzene, and
4-(trans-4-propylcyclohexyl)-ethylbenzene.
7. The composition of claim 2 wherein the one or more liquid
crystals are represented by the formula: ##STR00011##
8. The composition of claim 2 wherein the one or more liquid
crystals are selected from the group consisting of
4-(hexyloxy)phenyl 4-(heptyloxy)benzoate, 4-pentylphenyl
4-(heptyloxy)benzoate 4-pentylphenyl 4-(heptyloxy)benzoate,
4-(hexyloxy)phenyl 4-(heptyloxy)benzoate and mixture Of them
9. The composition of claim 2 wherein the one or more liquid
crystals are represented by the formula: A-(R3).sub.n wherein A is
a mono-ring or a multi-ring aromatic group, R3 is the same or
different and is a substituted or unsubstituted, hydrocarbon group
having from about 2 to about 24 carbon atoms, and n is a value from
about 1 to about 12.
10. The composition of claim 2 wherein the one or more liquid
crystals are represented by the formula: ##STR00012##
11. The composition of claim 2 wherein the one or more liquid
crystals comprise hexakis(octylthio)benzene.
12. The composition of claim 1 wherein the at least one base heat
transfer fluid has a freezing point of at least greater than about
-50.degree. C. as determined by ASTM D1777-17, a boiling point of
greater than about 100.degree. C. as determined by ASTM D1120-17,
and a flash point of at least 50.degree. C. as determined by ASTM
D93-16a.
13. The composition of claim 1 further comprising one or more of a
corrosion inhibitor, a thermal stabilizer, a pH stabilizer or
buffer, an antiscaling agent, a viscosity modifier, or a
biocide.
14. The composition of claim 1 further comprising one or more
lubricating oils to form a bimodal blend, wherein the one or more
lubricating oils comprise a Group I, Group II, Group III, Group IV,
or Group V oil, and mixtures thereof.
15. The composition of claim 1 wherein the heat transfer process is
carried out at a temperature and/or pressure sufficient to cause
the at least one base heat transfer fluid to undergo one or more
phase changes.
16. The composition of claim 1 wherein the heat transfer process is
carried out at a temperature from about -40.degree. C. to greater
than about 80.degree. C., and/or a pressure from about 50 MP to
about 500 MP.
17. A blend composition for enhanced heat transfer fluid
performance, said blend composition comprising: (i) at least one
base heat transfer fluid, and (ii) one or more lubricating oils
comprising a Group I, Group II, Group III, Group IV, or Group V
oil; wherein the at least one base heat transfer fluid undergoes
one or more phase changes in a heat transfer process, wherein the
heat transfer process comprises a heated zone and/or a cooled zone,
wherein the one or more phase changes increase heat removal from
the heated zone and/or increase heat rejection in the cooled zone,
as compared to heat removal from a heated zone and/or heat
rejection in a cooled zone of a heat transfer process having a base
heat transfer fluid that does not undergo one or more phase
changes.
18. A method for conducting heat transfer in a heating and/or
cooling system, said method comprising: (a) providing a composition
comprising at least one base heat transfer fluid in the heating
and/or cooling system; and (b) conducting heat transfer between the
at least one base heat transfer fluid and the heating and/or
cooling system; wherein the least one base heat transfer fluid
undergoes one or more phase changes in the heating and/or cooling
system, wherein the one or more phase changes increase heat removal
from the heating system and/or increase heat rejection in the
cooling system, as compared to heat removal from a heating system
and/or heat rejection in a cooling system having a base heat
transfer fluid that does not undergo one or more phase changes.
19. The method of claim 18 wherein the at least one base heat
transfer fluid comprises liquid crystals.
20. The method of claim 18 wherein the at least one base heat
transfer fluid comprises one or more smectic or discotic liquid
crystals.
21. The method of claim 19 wherein the one or more liquid crystals
are represented by the formula: R1-(A).sub.m-Y--(B).sub.n--R2
wherein R1 and R2 are the same or different and are a substituted
or unsubstituted, alkyl group or alkoxy group having from about 2
to about 24 carbon atoms; A and B are the same or different and are
a cycloaliphatic group or aromatic group, provided at least one of
A and B is an aromatic group; Y is a covalent bond, --CH2-CH2-,
--CH.dbd.CH--, --COO--, --CO--, --CSO--, --CSS--, --CS--, --O--,
--S--, --SO--, --SO2-, or --CH2O--; and m and n are independently
0, 1, 2 or 3.
22. The method of claim 19 wherein the one or more liquid crystals
are represented by the formula: ##STR00013## or
23. The method of claim 19 wherein the one or more liquid crystals
are selected from the group consisting of
4'-n-octyl-4-cyano-biphenyl,
4-(trans-4-heptylcyclohexyl)-pentylbenzene,
4-(trans-4-heptylcyclohexyl)-propylbenzene, and
4-(trans-4-propylcyclohexyl)-ethylbenzene.
24. The method of claim 19 wherein the one or more liquid crystals
are represented by the formula: A-(R3).sub.n wherein A is a
mono-ring or a multi-ring aromatic group, R3 is the same or
different and is a substituted or unsubstituted, hydrocarbon group
having from about 2 to about 24 carbon atoms, and n is a value from
about 1 to about 12.
25. The method of claim 19 wherein the one or more liquid crystals
are represented by the formula: ##STR00014##
26. The method of claim 19 wherein the one or more liquid crystals
comprise hexakis(octylthio)benzene.
27. The method of claim 18 wherein the at least one base heat
transfer fluid has a freezing point of at least greater than about
-50.degree. C. as determined by ASTM D1777-17, a boiling point of
greater than about 100.degree. C. as determined by ASTM D1120-17,
and a flash point of at least 50.degree. C. as determined by ASTM
D93-16a.
28. The method of claim 18 wherein the composition further
comprises one or more of a corrosion inhibitor, a thermal
stabilizer, a pH stabilizer or buffer, an antiscaling agent, a
viscosity modifier, or a biocide.
29. The method of claim 18 wherein the composition further
comprises one or more lubricating oils to form a bimodal blend,
wherein the one or more lubricating oils comprise a Group I, Group
II, Group III, Group IV, or Group V oil, and mixtures thereof.
30. The method of claim 18 further comprising conducting heat
transfer between the at least one base heat transfer fluid and the
heating and/or cooling system at a temperature and/or pressure
sufficient to cause the at least one base heat transfer fluid to
undergo one or more phase changes.
31. The method of claim 18 further comprising conducting heat
transfer between the at least one base heat transfer fluid and the
heating and/or cooling system at a temperature from about
-40.degree. C. to greater than about 80.degree. C., and/or a
pressure from about 50 MP to about 500 MP.
32. A method of heat transfer comprising: (a) providing an object
to be heated or cooled; and (b) transferring heat to or from the
object to be heated or cooled by a composition comprising at least
one base heat transfer fluid, wherein the least one base heat
transfer fluid undergoes one or more phase changes, wherein the one
or more phase changes increase heat removal from the object and/or
increase heat rejection in the object, as compared to heat removal
from an object and/or heat rejection in an object by a base heat
transfer fluid that does not undergo one or more phase changes.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Application No. 62/611,057, filed on Dec. 28, 2017, the entire
contents of which are incorporated herein by reference.
[0002] In addition, this application also claims the benefit of
related U.S. Provisional Application Nos. 62/611,072 and
62/611,081, both filed on Dec. 28, 2017, the entire contents of
which are also incorporated herein by reference.
FIELD
[0003] This disclosure relates to high performance heat transfer
fluids based on heat rejection and adsorption during fluid phase
changes. Also, this disclosure relates to a method for conducting
heat transfer in a heating and/or cooling system using a heat
transfer fluid based on heat rejection and adsorption during fluid
phase changes. The heat transfer fluids can exhibit liquid crystal
behavior.
BACKGROUND
[0004] Transfer of heat from local high temperature zones is a
critical performance feature of lubricants and circulating fluids.
In lubricated systems, examples of heat sources that require
cooling include, but is not limited to, heat generated by
combustion processes, heat resulting from friction within a
lubricated contact, heat created by energy sources, and heat used
in manufacturing processes (e.g., paper and steel making).
[0005] In some cases, specialized fluids are used for the sole
purpose of removing heat from high temperature zones. Examples
include coolants used in internal combustion engine applications,
and transformer oils used to cool electrical distribution
equipment. More recently, requirements to cool the battery and
power generation systems in electric and hybrid vehicles has
emerged as another application for fluids aimed at removing
heat.
[0006] Traditional fluids remove heat via combinations of
conductivity and convection mechanisms. The heat removed is a
function of fluid properties such as heat capacity and thermal
conductivity, system design including selection of materials that
determine the heat flow across fluid/surface interfaces, and
operational factors such as fluid flow rate and temperature
difference between fluid and the high temperature zone requiring
cooling.
[0007] Improving heat transfer is an emerging need as energy
density of systems and equipment increases. Improving thermodynamic
efficiency is often coupled with higher operating temperatures.
There are emerging requirements to provide cooling fluids for
hybrid and electric vehicles. Currently traditional cooling fluids,
including formulated lubricants are being used. These have limited
property ranges that will be extended using the liquid crystal
approach.
[0008] Other approaches include the use of higher density fluids
and suspension of solid nano particles. The range of performance of
the former is relatively limited. Use of nano particles has looked
promising but relies on being able to disperse sufficient quantity
of the particles. There are also health and safety concerns
regarding the use of engineered nano particles.
[0009] Performance of conventional heat transfer fluids is related
to fluid properties such as specific heat capacity and
conductivity. For most fluids, these properties fall within a
narrow range and limit potential heat transfer performance.
[0010] A major challenge in heat transfer fluids is the development
of alternate pathways to heat transfer performance for emerging
needs as energy density of systems and equipment increases.
SUMMARY
[0011] This disclosure relates to high performance heat transfer
fluids based on heat rejection and adsorption during fluid phase
changes. Also, this disclosure relates to a method for conducting
heat transfer in a heating and/or cooling system using a heat
transfer fluid based on heat rejection and adsorption during fluid
phase changes. The heat transfer fluids can exhibit liquid crystal
behavior.
[0012] This disclosure relates in part to a composition for
enhanced heat transfer fluid performance. The composition comprises
at least one base heat transfer fluid. The at least one base heat
transfer fluid undergoes one or more phase changes in a heat
transfer process. The heat transfer process comprises a heated zone
and/or a cooled zone. The one or more phase changes increase heat
removal from the heated zone and/or increase heat rejection in the
cooled zone, as compared to heat removal from a heated zone and/or
heat rejection in a cooled zone of a heat transfer process having a
base heat transfer fluid that does not undergo one or more phase
changes.
[0013] This disclosure also relates in part to a blend composition
for enhanced heat transfer fluid performance. The blend composition
comprises: (i) at least one base heat transfer fluid, and (ii) one
or more lubricating oils comprising a Group I, Group II, Group III,
Group IV, or Group V oil. The at least one base heat transfer fluid
undergoes one or more phase changes in a heat transfer process. The
heat transfer process comprises a heated zone and/or a cooled zone.
The one or more phase changes increase heat removal from the heated
zone and/or increase heat rejection in the cooled zone, as compared
to heat removal from a heated zone and/or heat rejection in a
cooled zone of a heat transfer process having a base heat transfer
fluid that does not undergo one or more phase changes.
[0014] This disclosure further relates in part to a method for
conducting heat transfer in a heating and/or cooling system. The
method comprises: (a) providing a composition comprising at least
one base heat transfer fluid in the heating and/or cooling system;
and (b) conducting heat transfer between the at least one base heat
transfer fluid and the heating and/or cooling system. The least one
base heat transfer fluid undergoes one or more phase changes in the
heating and/or cooling system. The one or more phase changes
increase heat removal from the heating system and/or increase heat
rejection in the cooling system, as compared to heat removal from a
heating system and/or heat rejection in a cooling system having a
base heat transfer fluid that does not undergo one or more phase
changes.
[0015] This disclosure yet further relates in part to a method of
heat transfer comprising: (a) providing an object to be heated or
cooled; and (b) transferring heat to or from the object to be
heated or cooled by a composition comprising at least one base heat
transfer fluid. The least one base heat transfer fluid undergoes
one or more phase changes. The one or more phase changes increase
heat removal from the object and/or increase heat rejection in the
object, as compared to heat removal from an object and/or heat
rejection in an object by a base heat transfer fluid that does not
undergo one or more phase changes.
[0016] It has been surprisingly found that, in accordance with this
disclosure, enhanced heat transfer fluid performance is achieved
using a composition comprising a base heat transfer fluid that
undergoes one or more phase changes, in which the one or more phase
changes increase heat removal from a heated zone and/or increase
heat rejection in a cooled zone of a heat transfer process, as
compared to heat removal from a heated zone and/or heat rejection
in a cooled zone of a heat transfer process having a base heat
transfer fluid that does not undergo one or more phase changes.
[0017] In particular, it has been surprisingly found that, in
accordance with this disclosure, enhanced heat transfer fluid
performance is achieved using a composition comprising a base heat
transfer fluid that exhibits liquid crystal behavior (e.g., a heat
transfer fluid having smectic and/or discotic liquid crystals), in
which the liquid crystal behavior increases heat removal from a
heated zone and/or increase heat rejection in a cooled zone of a
heat transfer process, as compared to heat removal from a heated
zone and/or heat rejection in a cooled zone of a heat transfer
process having a base heat transfer fluid that does not exhibit
liquid crystal behavior.
[0018] It has been surprisingly found that, in accordance with this
disclosure, enhanced heat transfer fluid performance and fluid flow
properties are achieved using a blend composition comprising a base
heat transfer fluid that undergoes one or more phase changes, in
which the one or more phase changes increase heat removal from a
heated zone and/or increase heat rejection in a cooled zone of a
heat transfer process, as compared to heat removal from a heated
zone and/or heat rejection in a cooled zone of a heat transfer
process having a base heat transfer fluid that does not undergo one
or more phase changes. The blend composition comprises (i) the at
least one base heat transfer fluid, and (ii) one or more
lubricating oils comprising a Group I, Group II, Group III, Group
IV, or Group V oil.
[0019] In particular, it has been surprisingly found that, in
accordance with this disclosure, enhanced heat transfer fluid
performance and fluid flow properties are achieved using a blend
composition comprising a base heat transfer fluid that exhibits
liquid crystal behavior (e.g., a heat transfer fluid having smectic
and/or discotic liquid crystals), in which the liquid crystal
behavior increases heat removal from a heated zone and/or increase
heat rejection in a cooled zone of a heat transfer process, as
compared to heat removal from a heated zone and/or heat rejection
in a cooled zone of a heat transfer process having a base heat
transfer fluid that does not exhibit liquid crystal behavior. The
blend composition comprises (i) the at least one base heat transfer
fluid, and (ii) one or more lubricating oils comprising a Group I,
Group II, Group III, Group IV, or Group V oil.
[0020] Other objects and advantages of the present disclosure will
become apparent from the detailed description that follows.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 shows DSC results for S2 liquid crystal during
heating cycle showing heat adsorption during phase change, in
accordance with the Examples.
[0022] FIG. 2 shows DSC results for the same S2 liquid crystal
during cooling cycle showing heat rejection during phase change, in
accordance with the Examples.
[0023] FIG. 3 graphically depicts results from a falling body high
pressure viscometer conducted on S2 liquid crystal, in accordance
with the Examples.
[0024] FIG. 4 graphically depicts similar results to FIG. 3 for a
25% liquid crystal/75% 4cSt PAO blend, in accordance with the
Examples.
[0025] FIG. 5 shows DSC heating cycle results for 25%, 50% and 75%
blends of liquid crystal in 4 cSt PAO showing shift in heat
adsorption behavior versus the pure liquid crystal (FIG. 1), in
accordance with the Examples.
[0026] FIG. 6 shows DSC cooling cycle results for 25%, 50% and 75%
blends of liquid crystal in 4 cSt PAO showing shift in hear
rejection versus the pure liquid crystal (FIG. 2), in accordance
with the Examples.
[0027] FIG. 7 shows DSC data for the 4-(hexyloxy)phenyl
4-(heptyloxy)benzoate LC3 liquid crystal (Example 3).
[0028] FIG. 8 shows DSC data for the 4-pentylphenyl
4-(heptyloxy)benzoate L4 liquid crystal (Example 4).
[0029] FIG. 9 shows DSC data for the 4-pentylphenyl
4-(heptyloxy)benzoate L4 liquid crystal (Example 4).
[0030] FIG. 10 shows DSC data for the 4-(hexyloxy)phenyl
4-(heptyloxy)benzoate L6 liquid crystal (Example 6).
DETAILED DESCRIPTION
Definitions
[0031] "About" or "approximately." All numerical values within the
detailed description and the claims herein are modified by "about"
or "approximately" the indicated value, and take into account
experimental error and variations that would be expected by a
person having ordinary skill in the art.
[0032] "Liquid crystal" fluids mean highly anisotropic fluids that
exist between the boundaries of the solid and conventional
isotropic liquid phase. The phase is a result of long-range
orientational ordering among constituent molecules that occurs
within certain ranges or temperature in melts and solutions of many
organic compounds. The various liquid crystal phases may be
characterized by the type of ordering. Among these are namely
nematic, smectic or discotic phases.
[0033] "Smectic liquid crystals" refer to hydrocarbon molecules
that are arranged in layers, with the long molecular axes
approximately perpendicular to the laminar planes. The only long
range order extends along this axis, with the result that
individual layers can slip over each other (soap-like in nature). A
smectic phase of a liquid crystal can possess two directions of
order including one along the axis of molecular orientation, and
the other along the traverse axis where molecules show
layering.
[0034] "Major amount" as it relates to components included within
the lubricating oils of the specification and the claims means
greater than or equal to 50 wt. %, or greater than or equal to 60
wt. %, or greater than or equal to 70 wt. %, or greater than or
equal to 80 wt. %, or greater than or equal to 90 wt. % based on
the total weight of the lubricating oil.
[0035] "Minor amount" as it relates to components included within
the lubricating oils of the specification and the claims means less
than 50 wt. %, or less than or equal to 40 wt. %, or less than or
equal to 30 wt. %, or greater than or equal to 20 wt. %, or less
than or equal to 10 wt. %, or less than or equal to 5 wt. %, or
less than or equal to 2 wt. %, or less than or equal to 1 wt. %,
based on the total weight of the lubricating oil.
[0036] "Essentially free" as it relates to components included
within the lubricating oils of the specification and the claims
means that the particular component is at 0 weight % within the
lubricating oil, or alternatively is at impurity type levels within
the lubricating oil (less than 100 ppm, or less than 20 ppm, or
less than 10 ppm, or less than 1 ppm).
[0037] "Flat viscosity" temperature performance as it relates to
the lubricant base stocks and lubricating oils disclosed herein
mean that the viscosity does not vary as a function of temperature
over a temperature range from 20 to 100 deg. C.
[0038] "Other lubricating oil additives" as used in the
specification and the claims means other lubricating oil additives
that are not specifically recited in the particular section of the
specification or the claims. For example, other lubricating oil
additives may include, but are not limited to, antioxidants,
detergents, dispersants, antiwear additives, corrosion inhibitors,
viscosity modifiers, metal passivators, pour point depressants,
seal compatibility agents, antifoam agents, extreme pressure
agents, friction modifiers and combinations thereof.
[0039] "Other mechanical component" as used in the specification
and the claims means an electric vehicle component, a hybrid
vehicle component, a power train, a driveline, a transmission, a
gear, a gear train, a gear set, a compressor, a pump, a hydraulic
system, a bearing, a bushing, a turbine, a piston, a piston ring, a
cylinder liner, a cylinder, a cam, a tappet, a lifter, a gear, a
valve, or a bearing including a journal, a roller, a tapered, a
needle, and a ball bearing.
[0040] "Hydrocarbon" refers to a compound consisting of carbon
atoms and hydrogen atoms.
[0041] "Alkane" refers to a hydrocarbon that is completely
saturated. An alkane can be linear, branched, cyclic, or
substituted cyclic.
[0042] "Olefin" refers to a non-aromatic hydrocarbon comprising one
or more carbon-carbon double bond in the molecular structure
thereof.
[0043] "Mono-olefin" refers to an olefin comprising a single
carbon-carbon double bond.
[0044] "Cn" group or compound refers to a group or a compound
comprising carbon atoms at total number thereof of n. Thus, "Cm-Cn"
group or compound refers to a group or compound comprising carbon
atoms at a total number thereof in the range from m to n. Thus, a
C1-C50 alkyl group refers to an alkyl group comprising carbon atoms
at a total number thereof in the range from 1 to 50.
[0045] "Carbon backbone" refers to the longest straight carbon
chain in the molecule of the compound or the group in question.
"Branch" refer to any substituted or unsubstituted hydrocarbyl
group connected to the carbon backbone. A carbon atom on the carbon
backbone connected to a branch is called a "branched carbon."
[0046] "SAE" refers to SAE International, formerly known as Society
of Automotive Engineers, which is a professional organization that
sets standards for internal combustion engine lubricating oils.
[0047] "SAE J300" refers to the viscosity grade classification
system of engine lubricating oils established by SAE, which defines
the limits of the classifications in rheological terms only.
[0048] "Base stock" or "base oil" interchangeably refers to an oil
that can be used as a component of lubricating oils, heat transfer
oils, hydraulic oils, grease products, and the like.
[0049] "Lubricating oil" or "lubricant" interchangeably refers to a
substance that can be introduced between two or more surfaces to
reduce the level of friction between two adjacent surfaces moving
relative to each other. A lubricant base stock is a material,
typically a fluid at various levels of viscosity at the operating
temperature of the lubricant, used to formulate a lubricant by
admixing with other components. Non-limiting examples of base
stocks suitable in lubricants include API Group I, Group II, Group
III, Group IV, and Group V base stocks. PAOs, particularly
hydrogenated PAOs, have recently found wide use in lubricants as a
Group IV base stock, and are particularly preferred. If one base
stock is designated as a primary base stock in the lubricant,
additional base stocks may be called a co-base stock.
[0050] All kinematic viscosity values in this disclosure are as
determined pursuant to ASTM D445. Kinematic viscosity at
100.degree. C. is reported herein as KV100, and kinematic viscosity
at 40.degree. C. is reported herein as KV40. Unit of all KV100 and
KV40 values herein is cSt unless otherwise specified.
[0051] All viscosity index ("VI") values in this disclosure are as
determined pursuant to ASTM D2270.
[0052] All Noack volatility ("NV") values in this disclosure are as
determined pursuant to ASTM D5800 unless specified otherwise. Unit
of all NV values is wt %, unless otherwise specified.
[0053] All pour point values in this disclosure are as determined
pursuant to ASTM D5950 or D97.
[0054] All CCS viscosity ("CCSV") values in this disclosure are as
determined pursuant to ASTM 5293. Unit of all CCSV values herein is
millipascal second (mPas), which is equivalent to centipoise),
unless specified otherwise. All CCSV values are measured at a
temperature of interest to the lubricating oil formulation or oil
composition in question. Thus, for the purpose of designing and
fabricating engine oil formulations, the temperature of interest is
the temperature at which the SAE J300 imposes a minimal CCSV.
[0055] All percentages in describing chemical compositions herein
are by weight unless specified otherwise. "Wt. %" means percent by
weight.
[0056] All numerical values within the detailed description and the
claims herein are modified by "about" or "approximately" the
indicated value, and take into account experimental error and
variations that would be expected by a person having ordinary skill
in the art. The phrase "major amount" or "major component" as it
relates to components included within the lubricating oils of the
specification and the claims means greater than or equal to 50 wt.
%, or greater than or equal to 60 wt. %, or greater than or equal
to 70 wt. %, or greater than or equal to 80 wt. %, or greater than
or equal to 90 wt. % based on the total weight of the lubricating
oil. The phrase "minor amount" or "minor component" as it relates
to components included within the lubricating oils of the
specification and the claims means less than 50 wt. %, or less than
or equal to 40 wt. %, or less than or equal to 30 wt. %, or greater
than or equal to 20 wt. %, or less than or equal to 10 wt. %, or
less than or equal to 5 wt. %, or less than or equal to 2 wt. %, or
less than or equal to 1 wt. %, based on the total weight of the
lubricating oil. The phrase "essentially free" as it relates to
components included within the lubricating oils of the
specification and the claims means that the particular component is
at 0 weight % within the lubricating oil, or alternatively is at
impurity type levels within the lubricating oil (less than 100 ppm,
or less than 20 ppm, or less than 10 ppm, or less than 1 ppm). The
phrase "other lubricating oil additives" as used in the
specification and the claims means other lubricating oil additives
that are not specifically recited in the particular section of the
specification or the claims. For example, other lubricating oil
additives may include, but are not limited to, antioxidants,
detergents, dispersants, antiwear additives, corrosion inhibitors,
viscosity modifiers, metal passivators, pour point depressants,
seal compatibility agents, antifoam agents, extreme pressure
agents, friction modifiers and combinations thereof.
[0057] The compositions of this disclosure containing the base heat
transfer fluids have advantageous characteristics for corrosion
inhibition, and a high thermal capacity to protect the fluid from
degradation at high temperatures. A base heat transfer fluid means
the major constituent of the heat transfer fluid and typically is a
base stock or base oil.
[0058] In accordance with this disclosure, liquid crystals offer an
alternative and additive mechanism to conventional heat transfer
fluids, and are fully miscible with conventional hydrocarbon heat
transfer fluids. The alternative and additional mechanism provided
by the high performance heat transfer fluids based on heat
rejection and adsorption during fluid phase changes increases the
heat transfer performance. This effect can also work as a
performance booster for conventional heat transfer fluids.
[0059] Further, in accordance with this disclosure, classes of
materials have been identified that undergo complex solid/solid,
solid/liquid and liquid/liquid phase changes. An example of these
materials include liquid crystals which are partially ordered
materials that can undergo multiple phase changes while remaining
in a semi-solid/liquid state. When such fluids undergo a phase
change, the physical properties of the fluid can change and can
become anisotropic or return to isotropic behavior. During such
phase changes, the liquid crystal may reject or adsorb heat. It has
been surprisingly found that this feature of phase change behavior
can be used to enhance heat transfer mechanisms, increasing the
ability of the fluid to remove heat. This mechanism works in
addition to any heat adsorption that occurs as the fluid is heated
up, and thus adds to the total heat removal process.
[0060] This phase change behavior can be exploited in a traditional
cooling circuit system in which a fluid is circulated in a closed
system. In this case, the fluid is pumped through a high
temperature zone and as a result is heated up. The total energy
removed can be estimated from the fluid's specific heat capacity,
the temperature rise that the fluid undergoes and the mass of fluid
flowing through the system. The fluid is then passed through a
system designed to reject the heat returning the fluid to its
original temperature for recirculation into the hot zone. In
accordance with this disclosure, an additional heat transfer
mechanism associated with the phase changes can increase the heat
removal from the hot zone and/or heat rejection during cooling.
[0061] This disclosure provides high performance heat transfer
fluids based on heat rejection and adsorption during fluid phase
changes. A specific example includes fluids that exhibit liquid
crystal behavior.
[0062] Compositions that exhibit liquid crystal behavior include
base heat transfer fluids that contain liquid crystals (e.g.,
smectic and/or discotic liquid crystals) as described herein.
[0063] Heat transfer fluids that exhibit liquid crystal behavior
can be blended with lubricating oil base fluids in order to
optimize fluid flow properties while retaining the heat transfer
benefits associated with the liquid crystal phase changes, as
described herein. In an embodiment, the heat transfer fluids that
exhibit liquid crystal behavior can be blended with lubricating oil
base fluids, to form bimodal blends.
[0064] In addition to the base heat transfer fluids, the
compositions of this disclosure can contain additives. Illustrative
additives useful in the heat transfer fluids of this disclosure
include, for example, corrosion inhibitors, thermal stabilizers,
viscosity modifiers, pH stabilizers or buffers, antiscaling
additives, biocides, and the like.
[0065] Corrosion inhibitors are preferably selected from tolyl
triazole, benzotriazole, aspartic acid, sebacic acid, borax,
molybdic oxide, sodium molybdate dihydrate, morpholine, or a
combination of two or more thereof. Sodium molybdate dihydrate is
an advantageous additive in aluminium (Al) containing systems since
it works especially well as an Al corrosion inhibitor. The total
amount of corrosion inhibitor in the heat transfer fluid is
preferably from 0.01 to 0.5% (w/w).
[0066] Thermal stabilizers are preferably selected from tetra
(2-hydroxypropyl) ethylenediamine (also known as quadrol polyol),
polyethyleneglycol, pentaerythritol or a combination of two or more
thereof. The total amount of thermal stabilizer in the heat
transfer fluid is preferably from 0.1 to 1% (w/w). Sodium hydroxide
may also be added as a stabilizer in an amount of less than 0.05%
(w/w), although this is in addition to any thermal stabilizer that
may be present. Sodium hydroxide serves to stabilize the glycerine
component of the composition and is preferably present in an amount
of at least 0.01% (w/w).
[0067] A viscosity modifier in the heat transfer fluid assists in
controlling the viscosity of the fluid to an acceptable level. The
specific viscosity modifier and quantities of viscosity modifier
used can have the advantage of providing a desired viscosity and
also advantageous characteristics with regard to the inhibition of
corrosion and the stability of the heat transfer fluids, in
particular thermal stability. They also can permit the use of known
anti-corrosion and anti-scaling additives. Illustrative viscosity
modifiers include, for example, triethanolamine, a glycerol
ethoxylate, and the like. The total amount of viscosity modifier in
the heat transfer fluid is preferably from 0.1 to 1% (w/w).
[0068] Illustrative pH stabilizers or buffers include, for example,
triisopropanol amine, borax, and the like. The total amount of pH
stabilizer or buffer in the heat transfer fluid is preferably from
0.01 to 0.5% (w/w).
[0069] Illustrative antiscaling additives include, for example,
sodium polyacrylate polymer, and the like. The total amount of
antiscaling additive in the heat transfer fluid is preferably from
0.01 to 0.5% (w/w).
[0070] Illustrative biocides include, for example, nipacide, and
the like. The total amount of biocide in the heat transfer fluid is
preferably from 0.01 to 0.5% (w/w).
[0071] The additives useful in this disclosure do not have to be
soluble in the heat transfer fluids. Insoluble additives in base
fluids can be dispersed in the heat transfer fluids of this
disclosure.
[0072] The types and quantities of performance additives used in
combination with the instant disclosure in heat transfer fluids are
not limited by the examples shown herein as illustrations.
[0073] When heat transfer fluid compositions contain one or more of
the additives discussed above, the additive(s) are blended into the
composition in an amount sufficient for it to perform its intended
function.
[0074] The foregoing additives are all commercially available
materials. These additives may be added independently but are
usually precombined in packages which can be obtained from
suppliers of heat transfer fluid additives. Additive packages with
a variety of ingredients, proportions and characteristics are
available and selection of the appropriate package will take the
requisite use of the ultimate composition into account.
[0075] The base heat transfer fluid as disclosed herein is
described in relation to the % (w/w) of each of the components
added. It will be appreciated that the balance of these components
is preferably the base heat transfer fluid. During manufacture,
some unavoidable impurities may be introduced into the fluid as
well. Preferably such unavoidable impurities should be less than 5%
(w/w), preferably less than 1% (w/w), more preferably less than
0.1% (w/w) and most preferably less than 0.01% (w/w). Ideally there
are no unavoidable impurities present.
[0076] With respect to the compositions of this disclosure, the at
least one heat transfer fluid has a freezing point of at least
greater than about -50.degree. C., or greater than about
-45.degree. C., or greater than about -40.degree. C., as determined
by ASTM D1777-17, a boiling point of greater than about 100.degree.
C., or greater than about 125.degree. C., or greater than about
150.degree. C., as determined by ASTM D1120-17, and a flash point
of at least 50.degree. C., or at least 60.degree. C., or at least
70.degree. C., as determined by ASTM D93-16a.
[0077] The heat transfer process is carried out at a temperature
from about -40.degree. C. to greater than about 80.degree. C., or
from about -35.degree. C. to greater than about 90.degree. C., or
from about -30.degree. C. to greater than about 100.degree. C.,
and/or a pressure from about 50 MP to about 500 MP, or from about
60 MP to about 475 MP, or from about 70 MP to about 450 MP.
Base Heat Transfer Fluids Containing Liquid Crystals
[0078] The base heat transfer fluids of this disclosure can be
comprised of liquid crystals such as S2 or analogs with differing R
group side chains or differing core structure still containing two
rings, at least one aromatic, with or without additional additives
or base stocks present, to give lower traction compared to
non-liquid crystal hydrocarbon fluids of the same viscosities. The
liquid crystals do not contain any heteroatoms.
[0079] The base heat transfer fluids of this disclosure can
comprise one or more liquid crystals. The one or more liquid
crystals are represented by the formula:
R1-(A).sub.m-Y--(B).sub.n--R2
wherein R1 and R2 are the same or different and are a substituted
or unsubstituted, hydrocarbon group alkyl group or alkoxy group
having from about 2 to about 24 carbon atoms; A and B are the same
or different and are a cycloaliphatic group or aromatic group,
provided at least one of A and B is an aromatic group; Y is a
covalent bond, --CH2-CH2-, --CH.dbd.CH--, --COO--, --CO--, --CSO--,
--CSS--, --CS--, --O--, --S--, --SO--, --SO2-, or --CH2O--; and m
and n are independently 0, 1, 2 or 3. The base heat transfer fluids
have a kinematic viscosity of about 2 cSt to about 28 cSt at
40.degree. C., as determined according to ASTM D445, and a
kinematic viscosity of about 1 cSt to about 12 cSt at 100.degree.
C., as determined according to ASTM D445.
[0080] Illustrative liquid crystals useful in this disclosure
include, for example, those represented by the formula:
##STR00001##
[0081] In particular, illustrative liquid crystals useful in this
disclosure include, for example, 4'-n-octyl-4-cyano-biphenyl,
4-(trans-4-heptylcyclohexyl)-pentylbenzene,
4-(trans-4-heptylcyclohexyl)-propylbenzene,
4-(trans-4-propylcyclohexyl)-ethylbenzene, and mixtures
thereof.
[0082] Other liquid crystals useful in this disclosure additionally
include, 4-pentylphenyl, 4-methylbenzoate, 4-pentylphenyl
4-ethylbenzoate, 4-pentylphenyl 4-propylbenzoate, 4-pentylphenyl
4-butylbenzoate, 4-pentylphenyl 4-(octyloxy)benzoate,
4-pentylphenyl 4-methoxybenzoate, 4-pentylphenyl 4-ethoxybenzoate,
4-pentylphenyl 4-propoxybenzoate, 4-pentylphenyl 4-butoxybenzoate,
4-pentylphenyl 4-pentoxybenzoate, and mixtures thereof.
##STR00002##
[0083] Other liquid crystals include 4-(hexyloxy)phenyl
4-(heptyloxy)benzoate, 4-pentylphenyl 4-(heptyloxy)benzoate,
4-(hexyloxy)phenyl 4-(heptyloxy)benzoate, 4-pentylphenyl
4-heptylbenzoate.
[0084] Also, the base heat transfer fluids of this disclosure can
comprise one or more discotic liquid crystals. The one or more
discotic liquid crystals are represented by the formula:
A-(R3).sub.n
wherein A is a mono-ring or a multi-ring aromatic group, R3 is the
same or different and is a substituted or unsubstituted,
hydrocarbon group having from about 2 to about 24 carbon atoms, and
n is a value from about 1 to about 12. The base heat transfer
fluids have a kinematic viscosity of about 2 cSt to about 28 cSt at
40.degree. C., as determined according to ASTM D445, and a
kinematic viscosity of about 1 cSt to about 12 cSt at 100.degree.
C., as determined according to ASTM D445.
[0085] Illustrative discotic liquid crystals useful in this
disclosure include, for example, those represented by the
formula:
##STR00003##
[0086] In particular, illustrative discotic liquid crystals useful
in this disclosure include, for example, hexakis(octylthio)benzene,
and mixtures thereof.
[0087] The liquid crystal materials of this disclosure access a
state of matter that is both fluid and anisotropic in
nature--essentially these materials are not solids, which possess a
highly ordered crystalline structure and lack ability of
translation of molecules in any direction, and they are not
liquids, which are characterized by their lack of order but
intermolecular forces that overcome kinetic energy, keeping them in
a condensed phase. Instead liquid crystals can be considered
"partly ordered" in that in some direction(s) they may appear
ordered, and in others they may appear disordered. These materials
are therefore anisotropic in nature, and the amount of ordering
seen depends on from which angle they are viewed.
[0088] Accordingly, as used herein, "liquid crystal" means highly
anisotropic fluids that exist between the boundaries of the solid
and conventional isotropic liquid phase. The phase is a result of
long-range orientational ordering among constituent molecules that
occurs within certain ranges or temperature in melts and solutions
of many organic compounds.
[0089] As used herein, "smectic liquid crystals" refers to
hydrocarbon molecules that are arranged in layers, with the long
molecular axes approximately perpendicular to the laminar planes.
The only long range order extends along this axis, with the result
that individual layers can slip over each other (soap-like in
nature). A smectic phase of a liquid crystal can possess two
directions of order including one along the axis of molecular
orientation, and the other along the traverse axis where molecules
show layering.
[0090] As used herein, "discotic liquid crystals" refers to
hydrocarbon molecules that are arranged in layers. Discotic phase
liquid crystals include disc-shaped crystals in columnar phases.
Their molecules have a symmetric branched formula which can be
approximated by a flat disc. Discotic crystals demonstrate the
layered arrangement like smectic crystals. Their molecules lie in
the layer planes forming close hexagonal packing.
[0091] The liquid crystal base oils of this disclosure conveniently
have a kinematic viscosity, according to ASTM standards, of about 2
cSt to about 28 cSt (or mm.sup.2/s) at 40.degree. C. and preferably
of about 2.5 cSt to about 25 cSt (or mm.sup.2/s) at 40.degree. C.,
often more preferably from about 2.5 cSt to about 20 cSt at
40.degree. C. Also, the liquid crystal base oil conveniently has a
kinematic viscosity, according to ASTM standards, of about 1 cSt to
about 12 cSt (or mm.sup.2/s) at 100.degree. C. and preferably of
about 2.5 cSt to about 10.5 cSt (or mm.sup.2/s) at 100.degree. C.,
often more preferably from about 2.5 cSt to about 10 cSt at
100.degree. C.
[0092] Mixtures of liquid crystal base oils may be used if desired.
Bi-modal, tri-modal, and additional combinations of mixtures of
liquid crystal base oils and optional Group I, II, III, IV, and/or
V base stocks may be used if desired. With mixtures of liquid
crystal base oils and Group I, II, III, IV, and/or V base stocks,
the liquid crystal base oil is present is an amount ranging from
about 5 to about 99 weight percent or from about 10 to about 95
weight percent, preferably from about 50 to about 99 weight percent
or from about 70 to about 95 weight percent, and more preferably
from about 85 to about 95 weight percent, based on the total weight
of the composition. Preferably, with mixtures of liquid crystal
base oils and Group I, II, III, IV, and/or V base stocks, the
liquid crystal base oil is present is an amount ranging from about
50 to about 99 weight percent or from about 55 to about 95 weight
percent, preferably from about 60 to about 99 weight percent or
from about 70 to about 95 weight percent, and more preferably from
about 85 to about 95 weight percent, based on the total weight of
the composition.
[0093] The liquid crystal base oil typically is present in an
amount ranging from about 5 to about 99 weight percent or from
about 10 to about 95 weight percent, preferably from about 50 to
about 99 weight percent or from about 70 to about 95 weight
percent, and more preferably from about 85 to about 95 weight
percent, based on the total weight of the composition.
[0094] Preferably, the liquid crystal base oil constitutes the
major component of the engine, or other mechanical component, oil
lubricant composition of the present disclosure and typically is
present in an amount ranging from greater than about 50 to about 99
weight percent or from about 55 to about 95 weight percent,
preferably from about 60 to about 99 weight percent or from about
70 to about 95 weight percent, and more preferably from about 85 to
about 95 weight percent, based on the total weight of the
composition.
Blends of Base Heat Transfer Fluids and Lubricating Oil Base
Fluids
[0095] A wide range of optional lubricating base fluids is known in
the art. Optional lubricating base fluids that are useful in the
present disclosure are natural oils, mineral oils and synthetic
oils, and unconventional oils (or mixtures thereof) can be used
unrefined, refined, or rerefined (the latter is also known as
reclaimed or reprocessed oil). Unrefined oils are those obtained
directly from a natural or synthetic source and used without added
purification. These include shale oil obtained directly from
retorting operations, petroleum oil obtained directly from primary
distillation, and ester oil obtained directly from an
esterification process. Refined oils are similar to the oils
discussed for unrefined oils except refined oils are subjected to
one or more purification steps to improve at least one lubricating
oil property. One skilled in the art is familiar with many
purification processes. These processes include solvent extraction,
secondary distillation, acid extraction, base extraction,
filtration, and percolation. Rerefined oils are obtained by
processes analogous to refined oils but using an oil that has been
previously used as a feed stock.
[0096] Groups I, II, III, IV and V are broad base oil stock
categories developed and defined by the American Petroleum
Institute (API Publication 1509; www.API.org) to create guidelines
for lubricant base oils. Group I base stocks have a viscosity index
of between about 80 to 120 and contain greater than about 0.03%
sulfur and/or less than about 90% saturates. Group II base stocks
have a viscosity index of between about 80 to 120, and contain less
than or equal to about 0.03% sulfur and greater than or equal to
about 90% saturates. Group III stocks have a viscosity index
greater than about 120 and contain less than or equal to about
0.03% sulfur and greater than about 90% saturates. Group IV
includes polyalphaolefins (PAO). Group V base stock includes base
stocks not included in Groups I-IV. The table below summarizes
properties of each of these five groups.
TABLE-US-00001 Base Oil Properties Saturates Sulfur Viscosity Index
Group I <90 and/or >0.03% and .gtoreq.80 and <120 Group II
.gtoreq.90 and .ltoreq.0.03% and .gtoreq.80 and <120 Group III
.gtoreq.90 and .ltoreq.0.03% and .gtoreq.120 Group IV
polyalphaolefins (PAO) Group V All other base oil stocks not
included in Groups I, II, III or IV
[0097] Optional base oils for use in the heat transfer fluids of
the present disclosure are any of the variety of oils corresponding
to API Group I, Group II, Group III, Group IV, and Group V oils and
mixtures thereof, preferably API Group II, Group III, Group IV, and
Group V oils and mixtures thereof, more preferably the Group III to
Group V base oils due to their volatility, stability, viscometric
and cleanliness features.
[0098] The optional base oil is typically is present in an amount
ranging from about 5 to about 99 weight percent or from about 10 to
about 95 weight percent, preferably from about 50 to about 99
weight percent or from about 70 to about 95 weight percent, and
more preferably from about 85 to about 95 weight percent, based on
the total weight of the composition. The optional base oil may be
selected from any of the synthetic or natural oils typically used
as crankcase lubricating oils for spark-ignited and
compression-ignited engines. The optional base oil conveniently has
a kinematic viscosity, according to ASTM standards, of about 2.5
cSt to about 18 cSt (or mm.sup.2/s) at 100.degree. C. and
preferably of about 2.5 cSt to about 12.5 cSt (or mm.sup.2/s) at
100.degree. C., often more preferably from about 2.5 cSt to about
10 cSt. Mixtures of synthetic and natural base oils may be used if
desired. Bi-modal, tri-modal, and additional combinations of
mixtures of Group I, II, III, IV, and/or V base stocks may be used
if desired.
[0099] The blends of heat transfer base fluids and lubricating oil
base fluids useful in the present disclosure may additionally
contain one or more of the other commonly used performance
additives as described herein.
[0100] The blends of heat transfer fluids that exhibit liquid
crystal behavior with lubricating oil base fluids can optimize
fluid flow properties while retaining the heat transfer benefits
associated with the liquid crystal phase changes, as described
herein.
[0101] The blends of heat transfer base fluids and lubricating oil
base fluids useful in the present disclosure may additionally
contain one or more of the other commonly used performance
additives as described herein.
[0102] The heat transfer fluids of this disclosure can be used to
heat or cool an object and can be used in heating and cooling
systems for heating and cooling residential, commercial and
industrial buildings. The heat transfer fluids can be used in an
engine cooling system. To cool a vehicle having a radiator and an
engine block, the heat transfer fluid is moved through the engine
block to transfer heat from the engine block to the heat transfer
fluid. The heat transfer fluid then moves through the radiator to
transfer heat from the heat transfer fluid to the radiator and to
air surrounding the radiator.
[0103] When used in a heating and cooling system for a building,
the heat transfer fluid can be inserted into the pipes of the
heating and cooling system. The heating or cooling systems can
include a boiler, pipes, a radiator, and a pump. The heat transfer
fluid is then moved into contact with the boiler so that heat is
transferred from the boiler to the heat transfer fluid. The heat
transfer fluid then moves through the radiators of the heating and
cooling system and heat is transferred from the heat transfer fluid
to the radiators. Heat is then transferred from the radiators to
air surrounding the radiators and into the building to heat the air
in the building.
[0104] The heat transfer fluids of this disclosure can be stored in
steel, plastic, poly or stainless steel containers. The heat
transfer fluids can be pumped from the storage container into the
heating and cooling systems or the objects to be heated or cooled
by most types of pumps well known in the art such as gear, air,
diaphragm, roller, or piston.
[0105] The following non-limiting examples are provided to
illustrate the disclosure.
EXAMPLES
[0106] Fluids were prepared as described herein.
[0107] The base fluids used were smectic liquid crystal base fluid
(i.e., 4-(trans-4-heptylcyclohexyl)-pentylbenzene (referred to as
"S2 liquid crystal")) and PAO4 base fluid.
[0108] Testing results were obtained using differential scanning
calorimetry (DSC) and a high pressure falling body viscometer.
[0109] FIG. 1 shows DSC results for S2 liquid crystal during
heating cycle showing heat adsorption during phase change.
[0110] The DSC results shown in FIG. 1 reveal the heat adsorbed
during a phase change that occurs between 14.degree. C. to
17.degree. C. for S2 liquid crystal during the heating cycle. In
this experiment, the heat adsorbed was measured to be 100.4 J/g.
For comparison, fluid heat capacity for lubricant range
hydrocarbons is typically measured to be approximately 2.5
J/gK.
[0111] FIG. 2 shows DSC results for the same S2 liquid crystal
during cooling cycle showing heat rejection during phase change. As
shown in FIG. 2, there is an additional phase change occurring at
much lower temperature.
[0112] Liquid crystal phase changes result in differences in
rheological performance. These effects were examined using a high
pressure falling body viscometer. At combinations of pressure and
temperature, it was observed that the phase change was clearly
identified by a discrete change in the viscosity response. FIG. 3
shows the line defining the boundary of one of the phase changes
exhibited by S2 liquid crystal. The upper left is a region in which
normal fluid like behavior occurs, and the lower right corresponds
to the area in which flow becomes more restricted and semi-fluid
like. This shows that the transition temperature can be controlled
by changing the system pressure.
[0113] FIG. 3 graphically depicts results from high pressure
viscosity measurements conducted on S2 liquid crystal. The line
shows the points of transition associated with a phase change.
[0114] FIG. 3 graphically depicts results from a falling body high
pressure viscometer conducted on S2 liquid crystal, in accordance
with the Examples. At high temperature/low pressures, the fluid
maintains viscous properties. At high pressures/low temperatures,
the falling body remains suspended indicating that a phase
transition has occurred resulting in mixed visco-elastic behavior.
The line depicts the measured boundary between these phases as a
function of temperature and pressure.
[0115] Experiments were conducted on blends of S2 liquid crystal in
PAO. FIG. 4 shows a similar transition boundary as found for the
pure liquid crystal. The boundary is shifted toward lower
temperature and higher pressures. The results confirm that phase
change behavior occurs in mixtures as well as the pure materials.
FIG. 4 graphically depicts similar results to FIG. 3 for a 25%
liquid crystal/75% 4cSt PAO blend, in accordance with the Examples.
A similar phase change was observed and was shifted toward higher
pressures. Results indicate phase change behavior occurs for
mixtures.
[0116] FIG. 5 shows DSC heating cycle results for 25%, 50% and 75%
blends of liquid crystal in 4 cSt PAO showing shift in heat
adsorption behavior versus the pure liquid crystal (FIG. 1).
[0117] FIG. 6 shows DSC cooling cycle results for 25%, 50% and 75%
blends of liquid crystal in 4 cSt PAO showing shift in hear
rejection versus the pure liquid crystal (FIG. 2).
[0118] FIG. 7 shows DSC data for the 4-(hexyloxy)phenyl
4-(heptyloxy)benzoate LC3 liquid crystal (Example 3). In the
heating cycle, we see a phase transitions at 65.35.degree. C. and
85.91.degree. C. The region between these two temperatures is the
liquid crystalline region, where the material is still a liquid,
yet has orientational order. The cooling scan reveals the existence
of the liquid crystalline phase starting at 85.degree. C. with
super cooling.
[0119] FIG. 8 shows DSC data for the 4-pentylphenyl
4-(heptyloxy)benzoate L4 liquid crystal (Example 4). In the heating
cycle, we see a phase transitions at 42.degree. C. and 60.degree.
C. The region between these two temperatures is the liquid
crystalline region, where the material is still a liquid, yet has
orientational order. The cooling scan reveals the existence of the
liquid crystalline phase starting at 60.degree. C. with super
cooling.
[0120] FIG. 9 shows DSC data for the 4-pentylphenyl
4-(heptyloxy)benzoate L4 liquid crystal (Example 4). In the heating
cycle, we see a phase transitions at 42.degree. C. and 60.degree.
C. The region between these two temperatures is the liquid
crystalline region, where the material is still a liquid, yet has
orientational order. The cooling scan reveals the existence of the
liquid crystalline phase starting at 60.degree. C. with super
cooling.
[0121] FIG. 10 shows DSC data for the 4-(hexyloxy)phenyl
4-(heptyloxy)benzoate L6 liquid crystal (Example 6). In the heating
cycle, we see a phase transitions at 44.degree. C. and 61.degree.
C. The region between these two temperatures is the liquid
crystalline region, where the material is still a liquid, yet has
orientational order. The cooling scan reveals the existence of the
liquid crystalline phase starting at 60.degree. C. with super
cooling.
[0122] The Examples show that liquid crystal phase change behavior
can be used to design high performance heat transfer fluids. This
principle can be applied to any system which undergoes a phase
change which includes the class of materials known to exhibit
liquid crystal behavior. In addition, the principle can work with
other phase changes such as wax formation. The performance of these
fluids will be controlled by the structure of the liquid crystal,
system design and operation, and any blend components used in the
final fluid.
[0123] Series of benzoate liquid crystals (LC3-6) were synthesized
and characterized using spectroscopic and DSC measurements.
[0124] Series of benzoate esters (MWs 412, 396, 382, and 366) were
synthesized by using alkyl or alkoxy substituted benzoic acid and
alkyl or alkoxy substituted phenol to obtain ester products. In
this series phenyl benzoate portion of the molecule was kept
constant and flexible chain portion of the molecule was varied by
either --CH2- group or --O-- atom. Among various esterification
reactions, esterification using DCC (dicyclohexylcarbodiimide) and
DMAP (4-dimethylaminopyridine) catalyst was preferred as reaction
can be carried out under mild reaction conditions (room
temperature). The benzoic acid used were 4-(heptyloxy)benzoic acid
and 4-heptylbenzoic acid and phenol used were 4-(hexyloxy)phenol
and 4-pentylphenol. The four esters (L3, L4, L5 and L6) were
characterized using NMR and DSC. All four products are found to be
liquid crystals with varying phase transition temperature. Such
study would allow one to develop structure activity and potentially
can be used for model assisted synthesis of desired liquid crystal
molecule.
Example 1. Synthesis of 4-(hexyloxy)phenyl 4-(heptyloxy)benzoate
LC3
##STR00004##
[0125] 4-heptylbenzoic acid (MW 220.31, 4.0 g, 18.16 mmol),
4-(hexyloxy)phenol (MW 194.27, 3.53 g, 18.16 mmol),
N,N'-dicyclohexylcarbodiimide (DCC) (MW 206.33, 3.75 g, 18.16
mmol), and 4-(dimethylamino)pyridine (DMAP) (MW 122.17, 0.09 g,
0.73 mmol) were mixed in 40 ml of methylene chloride (DCM) in a
round bottom flask and stirred at room temperature overnight. The
completion of the reaction was monitored by thin layer
chromatography (TLC) using hexane/ethyl acetate as eluent. Then the
reaction mixture was washed with 1N HCl, H.sub.2O, 10%
Na.sub.2CO.sub.3, H.sub.2O, and brine; dried over MgSO.sub.4, and
concentrated under vacuum to give crude product, which was further
purified by silica gel column chromatography to give 5.21 g of
white solid product. .sup.1H NMR (CDCl.sub.3, 400 MHz) .delta. 8.10
(dt, 2H, ArH), .delta. 7.30 (d, 2H, ArH), .delta. 7.10 and 6.92
(dt, dt, 2H, 2H, ArH), .delta. 3.96 (t, 2H, ArOCH.sub.2--), .delta.
2.69 (t, 2H, ArCH.sub.2--), .delta. 1.78 (quin, 2H,
ArOCH.sub.2CH.sub.2--), .delta. 1.65 (quin, 2H,
ArCH.sub.2CH.sub.2--), .delta. 1.47 (quin, 2H,
ArOCH.sub.2CH.sub.2CH.sub.2--) .delta. 1.40-1.22 (m, 12H,
--CH.sub.2--), .delta. 0.93-0.87 (t, t, 6H, CH.sub.3--).
Example 2. Synthesis of 4-pentylphenyl 4-(heptyloxy)benzoate
LC4
##STR00005##
[0126] 4-(heptyloxy)benzoic acid (MW 236.31, 4.0 g, 16.93 mmol),
4-pentylphenol (MW 164.24, 2.78 g, 16.93 mmol),
N,N'-dicyclohexylcarbodiimide (DCC) (MW 206.33, 3.49 g, 16.93
mmol), and 4-(dimethylamino)pyridine (DMAP) (MW 122.17, 0.10 g,
0.85 mmol) were mixed in 60 ml of methylene chloride (DCM) in a
round bottom flask and stirred at room temperature overnight. The
completion of the reaction was monitored by thin layer
chromatography (TLC) using hexane/ethyl acetate as eluent. Then the
reaction mixture was washed with 1N HCl, H.sub.2O, 10%
Na.sub.2CO.sub.3, H.sub.2O, and brine; dried over MgSO.sub.4, and
concentrated under vacuum to give crude product, which was further
purified by silica gel column chromatography to give 4.36 g of
white solid product. .sup.1H NMR (CDCl.sub.3, 400 MHz) .delta. 8.13
(dt, 2H, ArH), .delta. 7.21 (d, 2H, ArH), .delta. 7.09 and 6.96
(dt, dt, 2H, 2H, ArH), .delta. 4.04 (t, 2H, ArOCH.sub.2--), .delta.
2.61 (t, 2H, ArCH.sub.2--), .delta. 1.82 (quin, 2H,
ArOCH.sub.2CH.sub.2--), .delta. 1.63 (quin, 2H,
ArCH.sub.2CH.sub.2--), .delta. 1.47 (quin, 2H,
ArOCH.sub.2CH.sub.2CH.sub.2--), .delta. 1.41-1.27 (m, 10H,
--CH.sub.2--), .delta. 0.90 (t, 6H, CH.sub.3--).
Example 3. Synthesis of 4-(hexyloxy)phenyl 4-(heptyloxy)benzoate
LC5
##STR00006##
[0127] 4-(heptyloxy)benzoic acid (MW 236.31, 6.0 g, 25.39 mmol),
4-(hexyloxy)phenol (MW 194.27, 6.93 g, 35.67 mmol),
N,N'-dicyclohexylcarbodiimide (DCC) (MW 206.33, 6.29 g, 30.47
mmol), and 4-(dimethylamino)pyridine (DMAP) (MW 122.17, 0.31 g,
2.54 mmol) were mixed in 90 ml of methylene chloride (DCM) in a
round bottom flask and stirred at room temperature overnight. The
completion of the reaction was monitored by thin layer
chromatography (TLC) using hexane/ethyl acetate as eluent. Then the
reaction mixture was washed with 1N HCl, H.sub.2O, 10%
Na.sub.2CO.sub.3, H.sub.2O, and brine; dried over MgSO.sub.4, and
concentrated under vacuum to give crude product, which was further
purified by silica gel column chromatography to give 7.92 g of
white solid product. .sup.1H NMR (CDCl.sub.3, 400 MHz) .delta. 8.12
(dt, 2H, ArH), .delta. 7.09 (dt, 2H, ArH), .delta. 6.97-6.90 (dt,
dt, 4H, ArH), .delta. 4.03 and 3.95 (t, t, 2H, 2H, ArOCH.sub.2--),
.delta. 1.85-1.75 (m, 4H, ArOCH.sub.2CH.sub.2--), .delta. 1.51-1.42
(m, 4H, ArOCH.sub.2CH.sub.2CH.sub.2--), .delta. 1.41-1.27 (m, 10H,
--CH.sub.2--), .delta. 0.93-0.88 (t, t, 6H, CH.sub.3--). .sup.13C
NMR (CDCl.sub.3, 100 MHz) .delta. 165.4, 163.6, 156.9, 144.5,
132.3, 122.6, 121.8, 115.2, 114.4, 68.5, 68.4, 31.9, 31.8, 29.4,
29.3, 29.2, 26.1, 25.9, 22.8, 14.23, 14.20.
Example 4. Synthesis of 4-pentylphenyl 4-heptylbenzoate LC6
##STR00007##
[0128] 4-heptylbenzoic acid (MW 220.31, 5.0 g, 22.69 mmol),
4-pentylphenol (MW 164.24, 5.6 g, 34.04 mmol),
N,N'-dicyclohexylcarbodiimide (DCC) (MW 206.33, 5.62 g, 27.23
mmol), and 4-(dimethylamino)pyridine (DMAP) (MW 122.17, 0.28 g,
2.27 mmol) were mixed in 90 ml of methylene chloride (DCM) in a
round bottom flask and stirred at room temperature overnight. The
completion of the reaction was monitored by thin layer
chromatography (TLC) using hexane/ethyl acetate as eluent. Then the
reaction mixture was washed with 1N HCl, H.sub.2O, 10%
Na.sub.2CO.sub.3, H.sub.2O, and brine; dried over MgSO.sub.4, and
concentrated under vacuum to give crude product, which was further
purified by silica gel column chromatography to give 7.06 g of
white milky liquid product. .sup.1H NMR (CDCl.sub.3, 400 MHz)
.delta. 8.10 (d, 2H, ArH), .delta. 7.30 (d, 2H, ArH), .delta. 7.21
and 7.10 (dt, dt, 2H, 2H, ArH), .delta. 2.69 and 2.61 (t, t, 2H,
2H, ArCH.sub.2--), .delta. 1.69-1.58 (m, 4H, ArCH.sub.2CH.sub.2--),
.delta. 1.40-1.22 (m, 12H, --CH.sub.2--), .delta. 0.92-0.87 (t, t,
6H, CH.sub.3--). .sup.13C NMR (CDCl.sub.3, 100 MHz) .delta. 165.5,
149.3, 149.1, 140.5, 130.4, 129.4, 128.7, 127.3, 121.5, 36.2, 35.5,
31.95, 31.6, 31.32, 31.31, 29.4, 29.3, 22.8, 22.7, 14.24, 14.2.
[0129] The high performing heat transfer fluids enable design of
smaller more efficient cooling systems and or ability to increase
overall heat removal rates.
PCT and EP Clauses:
[0130] 1. A composition for enhanced heat transfer fluid
performance, said composition comprising at least one base heat
transfer fluid, wherein the at least one base heat transfer fluid
undergoes one or more phase changes in a heat transfer process,
wherein the heat transfer process comprises a heated zone and/or a
cooled zone, wherein the one or more phase changes increase heat
removal from the heated zone and/or increase heat rejection in the
cooled zone, as compared to heat removal from a heated zone and/or
heat rejection in a cooled zone of a heat transfer process having a
base heat transfer fluid that does not undergo one or more phase
changes.
[0131] 2. The composition of clause 1 wherein the at least one base
heat transfer fluid comprises liquid crystals.
[0132] 3. The composition of clause 1 wherein the at least one base
heat transfer fluid comprises one or more nematic, smectic or
discotic liquid crystals.
[0133] 4. The composition of clause 2 wherein the one or more
liquid crystals are represented by the formula:
R1-(A).sub.m-Y--(B).sub.n--R2
wherein R1 and R2 are the same or different and are a substituted
or unsubstituted, alkyl group or alkoxy group having from 2 to 24
carbon atoms; A and B are the same or different and are a
cycloaliphatic group or aromatic group, provided at least one of A
and B is an aromatic group; Y is a covalent bond, --CH2-CH2-,
--CH.dbd.CH--, --COO--, --CO--, --CSO--, --CSS--, --CS--, --O--,
--S--, --SO--, --SO2-, or --CH2O--; and m and n are independently
0, 1, 2 or 3.
[0134] 5. The composition of clause 2 wherein the one or more
liquid crystals are represented by the formula:
##STR00008##
[0135] 6. The composition of clause 2 wherein the one or more
liquid crystals are selected from the group consisting of
4'-n-octyl-4-cyano-biphenyl,
4-(trans-4-heptylcyclohexyl)-pentylbenzene,
4-(trans-4-heptylcyclohexyl)-propylbenzene, and
4-(trans-4-propylcyclohexyl)-ethylbenzene.
[0136] 7. The composition of clause 2 wherein the one or more
liquid crystals are represented by the formula:
A-(R3).sub.n
wherein A is a mono-ring or a multi-ring aromatic group, R3 is the
same or different and is a substituted or unsubstituted,
hydrocarbon group having from 2 to 24 carbon atoms, and n is a
value from 1 to 12.
[0137] 8. The composition of clause 2 wherein the one or more
liquid crystals are represented by the formula:
##STR00009##
[0138] 9. The composition of clause 2 wherein the one or more
liquid crystals comprise hexakis(octylthio)benzene.
[0139] 10. The composition of clause 1 wherein the at least one
base heat transfer fluid has a freezing point of at least greater
than -50.degree. C. as determined by ASTM D1777-17, a boiling point
of greater than 100.degree. C. as determined by ASTM D1120-17, and
a flash point of at least 50.degree. C. as determined by ASTM
D93-16a.
[0140] 11. The composition of clause 1 wherein the heat transfer
process is carried out at a temperature and/or pressure sufficient
to cause the at least one base heat transfer fluid to undergo one
or more phase changes.
[0141] 12. The composition of clause 1 wherein the heat transfer
process is carried out at a temperature from -40.degree. C. to
greater than 80.degree. C., and/or a pressure from 50 MP to 500
MP.
[0142] 13. A blend composition for enhanced heat transfer fluid
performance, said blend composition comprising: (i) at least one
base heat transfer fluid, and (ii) one or more lubricating oils
comprising a Group I, Group II, Group III, Group IV, or Group V
oil; wherein the at least one base heat transfer fluid undergoes
one or more phase changes in a heat transfer process, wherein the
heat transfer process comprises a heated zone and/or a cooled zone,
wherein the one or more phase changes increase heat removal from
the heated zone and/or increase heat rejection in the cooled zone,
as compared to heat removal from a heated zone and/or heat
rejection in a cooled zone of a heat transfer process having a base
heat transfer fluid that does not undergo one or more phase
changes.
[0143] 14. A method for conducting heat transfer in a heating
and/or cooling system, said method comprising: (a) providing a
composition comprising at least one base heat transfer fluid in the
heating and/or cooling system; and (b) conducting heat transfer
between the at least one base heat transfer fluid and the heating
and/or cooling system; wherein the least one base heat transfer
fluid undergoes one or more phase changes in the heating and/or
cooling system, wherein the one or more phase changes increase heat
removal from the heating system and/or increase heat rejection in
the cooling system, as compared to heat removal from a heating
system and/or heat rejection in a cooling system having a base heat
transfer fluid that does not undergo one or more phase changes.
[0144] 15. A method of heat transfer comprising: (a) providing an
object to be heated or cooled; and (b) transferring heat to or from
the object to be heated or cooled by a composition comprising at
least one base heat transfer fluid, wherein the least one base heat
transfer fluid undergoes one or more phase changes, wherein the one
or more phase changes increase heat removal from the object and/or
increase heat rejection in the object, as compared to heat removal
from an object and/or heat rejection in an object by a base heat
transfer fluid that does not undergo one or more phase changes.
[0145] All patents and patent applications, test procedures (such
as ASTM methods, UL methods, and the like), and other documents
cited herein are fully incorporated by reference to the extent such
disclosure is not inconsistent with this disclosure and for all
jurisdictions in which such incorporation is permitted.
[0146] When numerical lower limits and numerical upper limits are
listed herein, ranges from any lower limit to any upper limit are
contemplated. While the illustrative embodiments of the disclosure
have been described with particularity, it will be understood that
various other modifications will be apparent to and can be readily
made by those skilled in the art without departing from the spirit
and scope of the disclosure. Accordingly, it is not intended that
the scope of the claims appended hereto be limited to the examples
and descriptions set forth herein but rather that the claims be
construed as encompassing all the features of patentable novelty
which reside in the present disclosure, including all features
which would be treated as equivalents thereof by those skilled in
the art to which the disclosure pertains.
[0147] The present disclosure has been described above with
reference to numerous embodiments and specific examples. Many
variations will suggest themselves to those skilled in this art in
light of the above detailed description. All such obvious
variations are within the full intended scope of the appended
claims.
* * * * *
References