Note: Descriptions are shown in the official language in which they were submitted.
2184658
2743R/B-01
TITLE
POUR POINT DEPRESSANTS AND THEIR USE
BACKGROUND OF THE INVENTION
The present invention relates to materials useful for lowering the pour
point of wax-containing liquid hydrocarbons, and compositions of and methods
for preparing the same.
Various types of distillate fuel oils such as diesel fuels, various oils of
lubricating viscosity, automatic transmission fluids, hydraulic oil, home
heating
oils, and crude oils and fractions thereof require the use of pour point
depressant
additives in order to allow them to flow freely at lower temperatures. Often
kerosene is included in such oils as a solvent for the wax, particularly that
present in distillate fuel oils. However, demands for kerosene for use in jet
fuel
has caused the amount of kerosene present in distillate fuel oils to be
decreased
over the years. This, in turn, has required the addition of wax crystal
modifiers
to make up for the lack of kerosene. Moreover, the requirement for pour point
depressant additives in crude oils can be even more important, since addition
of
kerosene is not considered to be economically desirable.
U.S. Patent 5,039,437, Martella et al., August 13, 1991, (and U.S. Patent
5,082,470, Martella et al., January 21, 1992, a division thereof) disclose
alkyl
phenol-formaldehyde condensates additives for improving the low temperature
flow properties of hydrocarbon oils. The polymer composition has a number
average molecular weight of at least about 3,000 and a molecular weight distri-
bution of at least about 1.5; in the alkylated phenol reactant the alkyl
groups are
essentially linear, have between 6 and 50 carbon atoms, and have an average
number of carbon atoms between about 12 and 26; and not more than about 10
mole % of the alkyl groups on the alkylated phenol have less than 12 carbon
atoms and not more than about 10 mole % of the alkyl groups on the alkylated
phenol have more than 26 carbon atoms.
U.S. Patent 4,565,460, Dorer, Jr., et al., January 14, 1986, (and U.S.
patents 4,559,155, Dec. 17, 1985, 4,565,550, Jan. 21, 1986, 4,575,526, Mar.
11,
1986, and 4,613,342, Sep. 23, 1986, divisions thereof), disclose
additive'combi-
nations for improving the cold flow properties of hydrocarbon fuel composi-
tions. The composition includes a pour point depressant which can be a hydro-
carbyl-substituted phenol of the formula (R*)a Ar-(OH)b wherein R* is
a hydrocarbyl group selected from the group consisting of hydrocarbyl groups
of from about 8 to about 39 carbon atoms and polymers of at least 30 carbon
2134658
2
atoms. Ar is an aromatic moiety which can include linked polynuclear aromatic
moieties represented by the general formula ar-(-Lng-ar-)-,,,(Q)n,,,,
wherein w is an integer of 1 to about 20. Each Lng is a bridging linkage of
the
type including alkylene linkages (e.g., --CH2- among others).
SUMMARY OF THE INVENTION
The present invention provides a method for reducing the pour point of a
wax-containing (e.g., paraffin-containing) liquid, comprising adding to said
liquid a'
pour-point reducing amount of a hydrocarbyl-substituted phenol having a number
average of at least 30 carbon atoms (preferably greater than 30 carbon atoms)
in the
hydrocarbyl-substituent, and an aldehyde of 1 to about 12 carbon atoms, or a
source
therefor. The invention further encompasses a wax-containing liquid
composition
comprising a wax-containing liquid, where the liquid exhibits a pour point
(prior to
treatment) of at least 4 C (40 F) and a pour-point reducing amount of the
above
pour point depressant.
Finally, the present invention comprises a method for preparing the
reaction product of (a) a hydrocarbyl-substituted phenol and (b) an aldehyde
of
1 to 12 carbon atoms. The method is particularly suitable when the hydrocarbyl
group contains at least 30 carbon atoms, but can also be employed with shorter
groups, e.g., alkyl groups of 24-28 carbon atoms.
DETAILED DESCRIPTION OF THE INVENTION
The first aspect of the present invention relates to a pour point depressant
comprising the reaction product of (a) a hydrocarbyl-substituted phenol having
a
number average of at least 30 carbon atoms in the hydrocarbyl-substituent, and
(b) an aldehyde of 1 to 12, preferably 1 to 4, carbon atoms, or a source
therefor.
Hydrocarbyl-substituted phenols are known materials, as is their method
of preparation. When the term "phenol" is used herein, it is to be understood
that this term is not generally intended to limit the aromatic group of the
phenol
to benzene (unless the context so indicates, for instance, in the Examples),
although benzene may be the preferred aromatic group. Rather, the term is to
be
understood in.,its broader sense to include hydroxy aromatic compounds in
general, for example, substituted phenols, hydroxy naphthalenes, and the like.
Thus, the aromatic group of a "phenol" can be mononuclear or polynuclear,
substituted, and, can include other types of aromatic groups as well.
The aromatic group of the hydroxyaromatic compound can thus be a
single aromatic nucleus such as a benzene nucleus, a pyridine nucleus, a thio-
phene nucleus, a 1,2,3,4-tetrahydronaphthalene nucleus, etc., or a polynuclear
2184658
3
aromatic moiety. Such polynuclear moieties can be of the fused type; that is,
wherein pairs of aromatic nuclei making up the aromatic group share two
points,
such as found in naphthalene, anthracene, the azanaphthalenes, etc.
Polynuclear
aromatic moieties also can be of the linked type wherein at least two nuclei
(either mono or polynuclear) are linked through bridging linkages to each
other.
Such bridging linkages can be chosen from the group consisting of carbon-to-
carbon single bonds between aromatic nuclei, ether linkages, keto linkages,
sulfide linkages, polysulfide linkages of 2 to 6 sulfur atoms, sulfinyl
linkages,
sulfonyl linkages, methylene linkages, alkylene linkages, di-(lower alkyl)
methylene linkages, lower alkylene ether linkages, alkylene keto linkages,
lower
alkylene sulfur linkages, lower alkylene polysulfide linkages of 2 to 6 carbon
atoms, amino linkages, polyamino linkages and mixtures of such divalent
bridging linkages. In certain instances, more than one bridging linkage can be
present in the aromatic group between aromatic nuclei. For example, a fluorene
nucleus has two benzene nuclei linked by both a methylene linkage and a
covalent bond. Such a nucleus may be considered to have 3 nuclei but only two
of them are aromatic. Normally, the aromatic group will contain only carbon
atoms in the aromatic nuclei per se, although other non-aromatic substitution,
such as in particular short chain alkyl substitution can also be present. Thus
methyl, ethyl, propyl, and t-butyl groups, for instance, can be present on the
aromatic groups, even though such groups may not be explicitly represented in
structures set forth herein.
Specific examples of single ring aromatic moieties are the following:
O(Et)nOH ItILIM
Et
Me OPr 17
J
N
2184558
4
Nit
Me ci HZ
H Hz CH2 - CH2
H2 H2
CH2 - CH
H2
etc., wherein Me is methyl, Et is ethyl or ethylene, as appropriate, and Pr is
n-
propyl.
Specific examples of fused ring aromatic moieties are:
O(EtO)nH
MeO
Me Me Me / \ NO2
N
3
2184658
MeO
\ / \ I /
etc.
When the aromatic moiety is a linked polynuclear aromatic moiety, it can
5 be represented by the general formula
ar(-L - ar-) w
wherein w is an integer of 1 to about 20, each ar is a single ring or a fused
ring
aromatic nucleus of 4 to about 12 carbon atoms and each L is independently
selected from the group consisting of carbon-to-carbon single bonds between ar
nuclei, ether linkages (e.g. -0-), keto linkages (e.g., -C(=0)-), sulfide
linkages
(e.g., -S-), polysulfide linkages of 2 to 6 sulfur atoms (e.g., -S-2-6),
sulfinyl
linkages (e.g., -S(O)-), sulfonyl linkages (e.g., -S(O)2-), lower alkylene
linkages _
(e.g., -CH2-, -CH2-CH2-, -CH2-CHR -), mono(lower alkyl)-methylene linkages
(e.g., -CHR -), di(lower alkyl)-methylene linkages (e.g.,-CR 2-), lower
alkylene
ether linkages (e.g., -CH2O-, -CH2O-CH2-, -CH2-CH2O-, -CH2CH2OCH2CH-2,
-CH2CHOCH2CH-, -CHR -0-, -CHR -0-CHR -,
R R
I I
-CH2CHOCHCH2-, etc.), lower alkylene sulfide linkages
I I
R R
(e.g., wherein one or more -0-'s in the lower alkylene ether linkages is
replaced
with a S atom), lower alkylene polysulfide linkages (e.g., wherein one or more
-
0- is replaced with a-S-2-6 group), amino linkages (e.g., -N-, -N-, -CH2N-,
H R
-CH2NCH2-, -alk-N-, where alk is lower alkylene, etc.), polyamino linkages
(e.g., -N(a1kN)1-10' where the unsatisfied free N valences are taken up with H
atoms or R groups), linkages derived from oxo- or keto- carboxylic acids
(e.g.)
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6
R2 O
, 1 11 R17_0R6
R3 x
wherein each of R1, R2 and R3 is independently hydrocarbyl, preferably alkyl
or alkenyl, most preferably lower alkyl, or H, R6 is H or an alkyl group and x
is
an integer ranging from 0 to about 8, and mixtures of such bridging linkages
(each R being a lower alkyl group).
Specific examples of linked moieties are:
~ I \ I O
H2
CH2 / / C \
\ ~ \ I /
~ \ S ~ \
/ /
Me Me
1 -10
2184658
~
Me
C
( -
Me
H
1 -10, etc
Usually all of these aromatic groups have no substituents except for
those specifically named. For such reasons as cost, availability, performance,
etc., the aromatic group is normally a benzene nucleus, a lower alkylene
bridged
benzene nucleus, or a naphthalene nucleus. Most preferably the aromatic group
is a single benzene nucleus.
This first reactant is a hydroxyaromatic compound, that is, a compound
in which at least one hydroxy group is directly attached to an aromatic ring.
The number of hydroxy groups per aromatic group will vary from 1 up to the
maximum number of such groups that the hydrocarbyl-substituted aromatic
moiety can accommodate while still retaining at least one, and preferably at
least two, positions, at least some of which are preferably adjacent (ortho)
to a
hydroxy group, which are suitable for further reaction by condensation with
aldehydes (described in detail below). Thus most of the molecules of the
reactant will have at least two unsubstituted positions. Suitable materials
can
include, then, hydrocarbyl-substituted catechols, resorcinols, hydroquinones,
and even pyrogallols and phloroglucinols. Most commonly each aromatic
nucleus, however, will bear one hydroxyl group and, in the preferred case when
a hydrocarbyl substituted phenol is employed, the material will contain one
benzene nucleus and one hydroxyl group. Of course, a small fraction of the
aromatic reactant molecules may contain zero hydroxyl substituents. For
instance, a minor amount of non-hydroxy materials may be present as an impu-
rity. However, this does not defeat the spirit of the inventions, so long as
the
2184658
8
starting material is functional and contains, typically, at least one hydroxyl
group per molecule.
The hydroxyaromatic reactant is similarly characterized in that it is
hydrocarbyl substituted. The term "hydrocarbyl substituent" or "hydrocarbyl
group" is used herein in its ordinary sense, which is well-known to those
skilled
in the art. Specifically, it refers to a group having a carbon atom directly
attached to the remainder of the molecule and having predominantly hydrocar-
bon character. Examples of hydrocarbyl groups include:
(1) hydrocarbon substituents, that is, aliphatic (e.g., alkyl or a;lkenyl),
alicyclic (e.g., cycloalkyl, cycloalkenyl) substituents, and aromatic-,
aliphatic-,
and alicyclic-substituted aromatic substituents, as well as cyclic
substituents
wherein the ring is completed through another portion of the molecule (e.g.,
two
substituents together form an alicyclic radical);
(2) substituted hydrocarbon substituents, that is, substituents containing
non-hydrocarbon groups which, in the context of this invention, do not alter
the
predominantly hydrocarbon substituent (e.g., halo (especially chloro and
fluoro), hydroxy, alkoxy, mercapto, alkylmercapto, nitro, nitroso, and
sulfoxy);
(3) hetero substituents, that is, substituents which, while having a pre-
dominantly hydrocarbon character, in the context of this invention, contain
other than carbon in a ring or chain otherwise composed of carbon atoms.
Heteroatoms include sulfur, oxygen, nitrogen, and encompass substituents as
pyridyl, furyl, thienyl and imidazolyl. In general, no more than two,
preferably
no more than one, non-hydrocarbon substituent will be present for every ten
carbon atoms in the hydrocarbyl group; typically, there will be no non-
hydrocarbon substituents in the hydrocarbyl group.
Preferably the hydrocarbyl group is an alkyl group. Typically the alkyl
group will contain at least 30 carbon atoms, or if the alkyl group is a
mixture of
alkyl groups, the mixture will contain on average at least 30 carbon atoms,
typically 31 to 400 carbon atoms, preferably 31 to 60 , and more preferably 32
to 50 or 45 carbon atoms. In a preferred embodiment, the alkyl group in the
composition will be a mixture of alkyl groups, which may vary in length from
one particular molecule to another. While a fraction of the molecules may
contain an alk~l group of fewer than 30 carbon atoms, the composition as a
whole will normally be characterized as having alkyl substitution of at least
30
carbon atoms in length. However, for certain embodiments of the present
invention the alkyl group can be shorter, containing fewer than 30 carbon
atoms,
21846J8
9
e.g., predominantly 24 to 28 carbon atoms. The alkyl groups, in any case, can
be derived from either linear or branched olefin reactants; linear are
sometimes
preferred, although the longer chain length materials tend to have increasing
proportions of branching. A certain amount of branching appears to be intro-
duced via a rearrangement mechanism during the alkylation process as well.
In a preferred embodiment, the hydrocarbyl groups employed comprise a
mixture of alkyl lengths of predominantly 30 to 36 carbon atoms, having a
number average carbon number of about 34.4 and a weight average carbon
number of about 35.4 This material is characterized as having approximately
the following chain length distribution:
C26 0.3% C40 3.8
C28 11.9 C42 2.9
C30 16.7 C44 2.3
C32 11.3 C46 1.8
C34 8.6 C48 1.5
C36 6.6 C50 1.4
C38 5.0 C52 1.3
The hydrocarbyl substituent thus contains a number average number of greater
than
30 carbon atoms. Such substituents are preferably alkyl groups wherein the num-
ber average number of carbon atoms in the alkyl chain is 31 - 40, more
preferably
32-38.
The hydrocarbyl group can be derived from the corresponding olefin; for
example, a C26 alkyl group is derived from a C26 alkene, preferably a 1-
alkene, a
C34 alkyl group is derived from a C34 alkene, and mixed length groups are
derived from the corresponding mixture of olefins. When the hydrocarbyl group
is a hydrocarbyl group having at least about 30 carbon atoms, however, it is
frequently an aliphatic group (or a mixture of such groups) made from homo- or
interpolymers (e.g., copolymers, terpolymers) of mono- and di-olefins having 2
to 10 carbon atoms, such as ethylene, propylene, butene-1, isobutene,
butadiene,
isoprene, 1-hexene, 1-octene, etc. For suitable use as a pour point
depressant, at
least a portion of the alkyl group or groups is preferably straight chain,
that is,
substantially linear. It is believed that this feature is preferred in order
to
permit the chain to more favorably interact with the chain structure of wax-
forming hydrocarbons. It is recognized that in many cases there will be a
methyl branch at the point of attachment of the alkyl chain to the aromatic
ring,
even when an a-olefin is employed. This is considered to be within the scope
2184658
of the meaning of straight chain or linear alkyl groups. Likewise, in some
cases
a fraction of the alkyl groups may contain lower alkyl branching at the point
of
attachment (or a position), possibly due to migration of the active site
during
the alkylation reaction. Typically, the olefins employed are 1-mono olefins
5 such as homopolymers of ethylene. These aliphatic hydrocarbyl groups can
also
be derived from halogenated (e.g., chlorinated or brominated) analogs of such
homo- or interpolymers. Such groups can, however, be derived from other
sources, such as monomeric high molecular weight alkenes (e.g., 1-
tetracontene)
and chlorinated analogs and hydrochlorinated analogs thereof, aliphatic petro-
10 leum fractions, particularly paraffin waxes and cracked and chlorinated
analogs
and hydrochlorinated analogs thereof, white oils, synthetic alkenes such as
those
produced by the Ziegler-Natta process (e.g., poly(ethylene) greases) and other
sources known to those skilled in the art. Any unsaturation in the hydrocarbyl
groups may be reduced or eliminated by hydrogenation according to procedures
known in the art. Preparation by routes or using materials which are substan-
,
tially free from chlorine or other halogens is sometimes preferred for environ-
mental reasons.
In one embodiment, a portion of the hydrocarbyl groups are derived from
polybutene. In another embodiment, a portion of the hydrocarbyl groups are
derived from polypropylene. In a preferred embodiment, the hydrocarbyl group
is derived from a mixture of substantially unbranched olefins, having chain
lengths predominantly of 30-36 carbon atoms, as described above.
More than one such hydrocarbyl group can be present, but usually no
more than 2 or 3 are present for each aromatic nucleus in the aromatic group.
Most typically only 1 hydrocarbyl group is present per aromatic moiety,
particu-
larly where the hydrocarbyl-substituted phenol is based on a single benzene
ring.
The attachment of a hydrocarbyl group to the aromatic moiety of the first
reactant of this invention can be accomplished by a number of techniques well
known to those skilled in the art. One particularly suitable technique is the
Friedel-Crafts reaction, wherein an olefin (e.g., a polymer containing an
olefinic
bond), or halogenated or hydrohalogenated analog thereof, is reacted with a
phenol in the presence of a Lewis acid catalyst. Methods and conditions for
carrying out such reactions are well known to those skilled in the art. See,
for
example, the discussion in the article entitled, "Alkylation of Phenols" in
"Kirk-
Othmer Encyclopedia of Chemical Technology", Third Edition, Vol. 2, pages
2184658
11
65-66, Interscience Publishers, a division of John Wiley and Company, N.Y.
Other equally appropriate and convenient techniques for attaching the hydrocar-
bon-based group to the aromatic moiety will occur readily to those skilled in
the '
art.
Example 1.
A 12-L, four-neck, round-bottom flask, equipped with thermocouple,
nitrogen purging tube (14L/hr (0.5 std. ft3/hr) N2), mechanical stirrer, Dean-
Stark trap, and Friedrich's condenser, is charged with 1901 g (20.2
equivalents)
distilled (95%) phenol. The phenol is heated with stirring to 100 C and 62.4 g
Amberlyst 15TM catalyst (from Rohm and Haas) is charged. The mixture is
further heated to 150 C and maintained for 1.5 hours, collecting 9.5 mL of a
colorless condensate in the trap. The mixture is maintained at 150 C while
2150 g of a C30+ a-olefin mixture from Chevron is charged over a 1.3 hr.
period;
thereafter the mixture is maintained at 150 C for an additional 5 hours. The
mixture is cooled to 120 C and filtered through a glass microfibrous filter
pad
to remove catalyst. The filtrate is stripped at 160 C at 1.5 kPa (11 mm Hg)
pressure. The resulting material is again filtered through a microfibrous
glass
filter pad at 120 C to give the product in the form of a liquid which
solidifies
into a waxy solid.
Example 2.
Into the apparatus described in Example 1 is charged 2140 g (22.8
equivalents) of distilled phenol. Nitrogen is purged at 31L/hr (1.1 std.
ft3/hr).
Upon heating to 100 C, 61.4 g Amberlyst 15TM catalyst is charged, and 14 mL
colorless condensate is collected. The mixture is maintained at 150 C while
2240 g of C24_28 a-olefins from Chevron are charged over a 1.5 hour period;
thereafter the mixture is maintained at 150 C for an additional 3 hours. The
mixture is cooled to 120 C and filtered through a glass microfibrous filter
pad
to remove catalyst. The filtrate is stripped at 150 C at 2.4 kPa (18 mm Hg)
for
0.5 hr. The resulting material is again filtered through a microfibrous glass
filter pad at 110 C to give the product in the form of a light yellow oil
which
solidifies into a white wax.
The second component which reacts to form the pour point depressant is
an aldehyde of' 1 to 12 carbon atoms, or a source therefor. Suitable aldehydes
have the general formula RC(O)H, where R is preferably hydrogen or a hydro-
carbyl group, as described above, although R can include other functional
groups which do not interfere with the condensation reaction (described below)
2184658
12
of the aldehyde with the hydroxyaromatic compound. This aldehyde preferably
contains 1 to 12 carbon atoms, more preferably 1 to 4 carbon atoms, and still
more preferably 1 or 2 carbon atoms. Such aldehydes include formaldehyde,
acetaldehyde, propionaldehyde, butyraldehyde, isobutyraldehyde, pentanal-
dehyde, caproaldehyde, benzaldehyde, and higher aldehydes. Monoaldehydes
are preferred. The most preferred aldehyde is formaldehyde, which can be
supplied as a solution, but is more commonly used in the polymeric form, as
paraformaldehyde. Paraformaldehyde may be considered a reactive equivalent
of, or a source for, an aldehyde. Other reactive equivalents may include hy-
drates or cyclic trimers of aldehydes.
The hydrocarbyl phenol and the aldehyde are generally reacted in relative
amounts ranging from molar ratios of phenol:aldehyde of 2:1 to 1:1.5. Prefera-
bly approximately equal molar amounts will be employed up to a 30% molar
excess of the aldehyde (calculated based on aldehyde monomer). Preferably the
amount of the aldehyde is 5 to 20, more preferably 8 to 15, percent greater
than
the hydrocarbyl phenol on a molar basis. The components are reacted under
conditions to lead to oligomer or polymer formation. The molecular weight of
the product will depend on features including the equivalent ratios of the
reac-
tants, the temperature and time of the reaction, and the impurities present.
The
product can have from 2 to 100 aromatic units (i.e., the substituted aromatic
phenol monomeric units) present ("repeating") in its chain, preferably 3 to 70
such units, more preferably 4 to 50, 30, or 14 units. When the hydrocarbyl
phenol is specifically an alkyl phenol having 24-28 carbon atoms in the alkyl
chain, and when the aldehyde is formaldehyde, the material will preferably
have
a number average molecular weight of 1,000 to 24,000, more preferably 2,000
to 18,000, still more preferably 3,000 to 6,000. The molecular weights of
materials based on a hydrocarbyl substituent length of about 34 carbon atoms
would be proportionally somewhat higher.
The hydrocarbyl phenol and the aldehyde are reacted by mixing the
alkylphenol and the aldehyde in an appropriate amount of diluent oil or, op-
tionally, another solvent such as an aromatic solvent, e.g., xylene, in the
pres-
ence of an acid such as sulfuric acid, a sulfonic acid such as an
alkylphenylsul-
fonic acid, para toluene sulfonic acid, or methane sulfonic acid, an organic
acid
such as glyoxylic acid, or AmberlystTM catalyst, a solid, macroporous, lightly
crosslinked sulfonated polystyrene-divinylbenzene resin catalyst from Rohm
and Haas. The mixture is heated, generally to 90 to 160 C, preferably 100 to
2184658
13
150 or to 120 C, for a suitable time, such as 30 minutes to 6 hours,
preferably 1
to 4, hours, to remove water of condensation. The time and temperature are
correlated so that reaction at a lower temperature will generally require a
longer
time, and so on. Determining the exact conditions is within the ability of the
person skilled in the art. If desired, the reaction mixture can thereafter be
heated to a higher temperature, e.g., 140-180 C, preferably 145-155 C, to
further drive off volatiles and move the reaction to completion. The product
can
be treated with base such as NaOH if desired, in order to neutralize the
strong
acid catalyst and to prepare a sodium salt of the product, if desired, and is
thereafter isolated by conventional techniques such as filtrationõas
appropriate.
The product of this reaction can be generally regarded as comprising
polymers or oligomers having the following repeating structure:
OH
/ CH2~
~ I
H H
R2 "
and positional isomers thereof.
However, a portion of the formaldehyde which is preferably employed is be-
lieved to be incorporated into the molecular structure in the form of
substituent
groups and linking groups such as those illustrated by the following types,
including ether linkages and hydroxymethyl groups:
OH H
'R j H2O CH2O CH2 Ra
H H H H
R2 R5
OH O,CH2.0
~R CH 2 1R
~ I OH
H ~ q
H H
R 2 R2
_ 2184658
14
OH H
1R / CH2'p CH2 / Ra
~
~ H Hp ~ H
R2 R5
Preparation of the pour point depressants by the above method provides a
material which generally exhibits improved handling properties such as in-
creased flash point, compared with pour point depressants prepared by prior
art
methods.
Exa le 3.
A 5-L flask assembly similar to that of Example 1 is charged with 1850 g
of the C30+ alkyl phenol from Example 1. The material is heated with stirring
to
100 C and 11.2 g concentrated. sulfuric acid is added over a 10 minute period,
immediately followed by a 9.6 g charge of paraformaldehyde (91%). Eleven
additional charges of paraformaldehyde are added over the next 3 hours, for a
total of 115 g, during which time condensate is collected in the trap. After
the 3
hour period, one drop of antifoam agent is added and the temperature is in-
creased to 115 C over 0.5 hour, maintained at this temperature for 2 hours,
followed by heating to 150 C over 0.3 hours and maintaining at this
temperature -
for 2.0 hours. 631 g of a commercial paraffinic high boiling solvent is added,
reducing the temperature to 131 C. To the mixture is added 18.4 g of 50
weight
% aqueous sodium hydroxide over a 10 minute period. The mixture is heated to
150 C for 0.5 hour and an additional 992 g of paraffinic solvent is added, as
well as 95 g of a filter aid. After an additional 1 hour at temperature, the
mixture is filtered at 75 C using additional filter aid, and the filter aid
washed
with an additional 292 g paraffinic solvent. The product is the filtrate,
which
contains about 50% paraffinic high boiling diluent.
Example 4.
A 1-L, four-neck, round-bottom flask equipped with a nitrogen purging
line, stirrer, thermowell, Dean-Stark trap, and Friedrich's condenser, is
charged
with 360.2 g (0.787 equivalents) of predominantly C24.28 alkyl-substituted
phenol. The charge is heated with stirring, under nitrogen flow of 14L/hr (0.5
std. ft3/hr), to 70 C, and 75 g commercial aromatic solvent diluent (initial
boiling point 179 C) is added. The mixture is heated to 100 C, and, over a 2.8
2184658
hour period, 28.89 g paraformaldehyde (91%; 0.875 equivalents) are added in
12 equal portions. After addition of the first portion, 2.06 g of concentrated
sulfuric acid is added, as well as 1 drop of a kerosene solution of a silicone
antifoam agent (Dow Corning TM 200 Fluid). After addition of the paraformal-
5 dehyde is complete, the mixture is heated to 115 C over 0.25 hours and main-
tained at this temperature for 1.7 hours, thereafter heated to 150 C over 0.4
hours and maintained at that temperature for 1.5 hours, and thereafter heated
to
156 C for about 0.5 hours. Addition of 295 g additional diluent aromatic
solvent
causes the temperature to drop to 122 C. Sodium hydroxide, 3.8 g of 50%
10 solution, is added, as well as 19.7 g of a filter aid (FAX-5TM). The
mixture is
again heated to 150 C. After 0.8 hours at 150 C, the mixture is cooled to less
than 50 C and is filtered to provide 728.2 g of a brown oil filtrate, which is
the
product, containing about 50% diluent.
Example 5.
15 The procedure of Example 4 is substantially repeated, except that a 5 L
flask is used. The flask is charged with 1870 g of the C24_2g-alkyl phe-
nol/formaldehyde condensate and 389 g o-xylene. Concentrated sulfuric acid,
11.3 g, is added at 80 C over a 10 minute period. Paraformaldehyde, 150g,
91%, is charged in 12 portions at 80-100 C over 3 hours, and water of conden-
sation is collected. Two drops of antifoam agent are added and the mixture
heated to 115 C for 2 hours, then to 150 C over 1 hour and maintained at that
temperature for 2 additional hours. Then 642 g of a commercial paraffinic high
boiling solvent is added, reducing the temperature to 131 C. To the mixture
is
added 17.9 g of 50 weight % aqueous sodium hydroxide dropwise over a 10
minute period. The mixture is heated to 150 C for 0.5 hour, then brought to
130 C at 8.6 kPa (65 mm Hg) for 1 hour. An additional 1283 g of commercial
paraffinic high boiling solvent is added, as well as 95 g of a filter aid.
After 1
hour of additional stirring, the mixture is filtered through 25 g additional
filter
aid at 110 C.
Example 6.
A 1-L, four-neck, round bottom flask equipped as in Example 4 is
charged with 360 g of C24_28-alkyl phenol and heated with stirring and under
nitrogen (17-29 L/hr (0.6-1.0 std. ft3/hr)) to 83 C. Concentrated sulfuric
acid,
2.2 g, is added and the mixture is heated to 101 C. Paraformaldehyde, 29.11 g
(91%), is added in 16 portions over a three hour period, and condensate is
collected. The mixture is heated to 115 C over 0.4 hours and maintained for
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1.75 hours, then heated to 150 C over 0.4 hours and maintained for 1.75 hours.
The mixture is allowed to cool to 125 C, and 4.09 g of 50% sodium hydroxide
is added. The mixture is heated to and held at 150 C for 1.0 hour. Then 371 g
of commercial paraffinic high boiling solvent is added as well as 22 g filter
aid.
The mixture is cooled somewhat and filtered using additional filter aid over a
period of 3 hours. The filtrate is the product.
Example 7.
To a 760-L glass-jacketed reaction vessel equipped with a stirrer, a
column, a condenser, a distillate receiver, and a nitrogen purge (570L/hr (20
std.
ft3/hr) is charged 155 kg C24_28-alkyl phenol and 31 kg commercial aromatic
solvent diluent. The mixture is heated, with stirring, to 79-85 C, whereupon
890 g concentrated sulfuric acid is added. The mixture is heated to 104-110 C
and 12.2 kg paraformaldehyde (91%) is added in 9 equal increments over 5-6
hours, removing aqueous distillate as it is generated. The mixture is heated
to
118-124 C over three hours and maintained at temperature for an additional 2
hours, then to 127 C while simultaneously adding 1.35 kg 50% aqueous sodium
hydroxide. The mixture is heated to 149-154 C over two hours (with increased _
nitrogen flow) to remove residual water. The mixture is cooled to 60 C, and
126 kg additional commercial aromatic solvent diluent is added, to provide 50%
diluent. The mixture is filtered at 60-66 C employing 2.7 kg filter aid.
Example 8.
The procedure of Example 7 is substantially repeated using in place of
the C24_2g-alkyl phenol a molar equivalent amount of C30+-alkyl phenol. For
this
example, no solvent is employed in the initial stage of the reaction, but the
amount added after the reaction is the amount calculated to provide 50% poly-
mer, 50% solvent. In an alternative embodiment of this Example, solvent is
employed as in Example 7.
The pour point depressant materials of this invention which have an
average alkyl chain length of at least 30 carbon atoms, are particularly
suitable
for reducing the pour point of certain petroleum oils, i.e., crude oils or
fractions
of crude oil, such as residual oil, vacuum gas oil, or vacuum residual oils
(Bunker C crude oils), that is, naturally sourced and partially refined oils,
including partihlly processed petroleum derived oils. The suitable oils are
generally those which have an initial (that is, unmodified, or prior to
treatment
with the pour point depressant) pour point of at least 4 C (40 F), preferably
at
least 10 C (50 F) or more preferably 16 C (60 F), although they also exhibit
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17
some advantage in certain oils which fall outside of these limits. The use of
the
present materials is particularly valuable in those crude oils which are
difficult
to treat by other means. For example, they are particularly useful in oils
(crude
oils and oil fractions such as those described above) which have a wax content
of greater than 5%, preferably greater than 10%, by weight as measured by
UOP-46-85 (procedure from UOP, Inc., "Paraffin wax content of petroleum oils
and asphalts"). (Wax-containing materials are sometimes also referred to as
paraffin-containing materials, paraffin being an approximate equivalent for
wax,
and in particular, for petroleum waxes. The present invention is not
particularly
limited to any specific type of wax which may cause the pour point phenomenon
in a given liquid. Thus paraffin wax, microcrystalline waxes, and other waxes
are encompassed. It is recognized that in many important materials, such as
petroleum oils, paraffin wax may be particularly important.) The pour point
depressant materials are further useful in oils with a large high-boiling
fraction,
that is, in which the fraction boiling between 271 C (520 F) and 538 C
(1000 F) (i.e., about C15 and above) comprises at least 25%, preferably at
least
30%, more preferably at least 35% of the oil (exclusive of any fraction of 7
or
fewer carbon atoms). Among high boiling oils, they are more particularly
useful if greater than 10%, preferably greater than 20%, more preferably
greater
than 30%, of the high boiling (271-538 C) fraction boils between 399 C
(750 F) and 538 C (1000 F) (i.e., about C25 and above), as measured by ASTM
D 5307-92. Preferably this highest boiling (399-538 C) fraction will comprise
at least 10% of the total oil (exclusive of any fraction of 7 or fewer carbon
atoms). Preferably the analysis is performed on stock tank crude which is
degassed and contains little or no fraction of C4 or below. They are further
useful in materials which have an API gravity of greater than 20 (ASTM D-
287-82).
The present pour point depressant material.are, in many cases, useful for
treating oils (e.g., crude oils and fractions thereof) which have a N, of
greater
than 18, preferably greater than 20, and more preferably greater than 22. Here
NW is the weight average number of carbon atoms of the molecules of the oil, =
defined by
~B *n2
NW = D
ED. *n
where Bn represents the weight percent of the crude boiling fraction of the
oil
containing the alkane C,,H2n+2 and n is the carbon number of the corresponding
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paraffin. These boiling fraction values are determined by ASTM procedure
D5307-92. Most preferably the suitable oils will have the above defined value
of NW, as well as one or more of the above-defined characteristics such as a
pour
point above 4 C and/or a wax content of greater than 5% (UOP-41-85 proce-
dure).
The amount of the pour point depressant employed in the oil or in the
other wax-containing liquid, will be an amount suitable to reduce the pour
point
thereof by a measurable amount, i.e., by at least 0.6 C (1 F), preferably at
least
2 C (3 or 4 F), more preferably 3 C (5 F), and even more preferably 6 C
(10 F). This reduction in pour point can be readily determined by one skilled
in -.
the art by employing the methodology of ASTM D- 97. Typically the amount of
pour point employed will be 50 to 10,000 parts per million by weight (ppm),
preferably 100 to 5000 ppm, more preferably 200 to 2000 ppm, based on the
fluid to which it is added.
Examples 9 - 16.
The pour point depressant prepared as in Example 3 is supplied in the
amounts indicated to various crude oils listed in the following Table, each of
which has an untreated pour point of at least 4 C. The pour point depressant
is
added in the conventional manner, that is, by mixing into the crude oil at a
temperature above the pour point of the oil, although other methods of
addition
will be apparent to those skilled in the art. The pour points are reduced as
indicated.
Ex.' Crude Oil PPD Treat, ppm Pour Point, C
9 Phillips 66TM South Marsh Island 0 4
#147, #10 F/L 500 2
10 SarirTM Libya Crude 0 24b
2000 11, 17b
11 AnadarkoTM Pet. Tucker #1 Okla- 0 24
homa 2000 -7
12 Lion ResourcesTM South American 0 13
500 -4
13 Control ServicesTM South Marsh 0 29
Island Gulf of Mexico 1000 27, 27b
2000 27, 24b
14 AandarkoTM Pet. Tucker #3 0 24,21 b
2000 2, 4b
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19
15 Lion ResourcesTM South American 0 16
2000 4
16 Mobi1TM heavy fuel oil, Egypt 0 35
2000 26
a another specimen shows untreated pour point of -1 C, +1 C
b duplicate runs
c one additional oil, normally exhibiting a pour point of 0 C, shows in one
sample a pour point of 13 C, reduced to 10 C by 500 ppm of the depressant
Figure 1 shows the composition of an Anadarko Tucker crude oil similar
to that of Examples 11 and 14, presented as % Weight as a function of Boiling
Fraction. The large peak for C40 in both cases represents the sum of compo-
nents boiling in the C40 range and above.
In some of the above formulations the cloud point, as well as the pour
point, is depressed.
The pour point depressants of the present invention can be supplied in
the pure form (containing 0% diluent) or as concentrates containing a diluent
such as a hydrocarbon oil. When supplied as a concentrate, the amount of oil
can be up to 90% of the composition, typically 10-90%, preferably 30-70%, and
more preferably 40-60%. Alternatively, the pour point depressants can be
supplied as dispersions in such materials acetates (e.g., as 2-ethoxyethyl
acetate)
or aqueous glycol mixtures (e.g., mixtures of ethylene glycol and water).
Each of the documents referred to above is incorporated herein by refer-
ence. Except in the Examples, or where otherwise explicitly indicated, all
numerical quantities in this description specifying amounts of materials, reac-
tion conditions, molecular weights, number of carbon atoms, and the like, are
to
be understood as modified by the word "about." Unless otherwise indicated,
each chemical or composition referred to herein should be interpreted as being
a
commercial grade material which may contain the isomers, by-products, deriva-
tives, and other such materials which are normally understood to be present in
the commercial grade. However, the amount of each chemical component is
presented exclusive of any solvent or diluent oil which may be customarily
present in the commercial material, unless otherwise indicated. As used
herein,
the expression "consisting essentially of' permits the inclusion of substances
which do not materially affect the basic and novel characteristics of the com-
position under consideration.
