CA1204900A - Ester-containing halopolyalkylenes - Google Patents

Abstract

Abstract of the Disclosure This invention relates to polyalkylenes which contain both halogen and ester groups, to the preparation thereof, and to the use thereof as pour depressants for fuel oils. This invention also relates to polyalkylene esters.

Description

90~) ESTER-CONTAINING HALOPOLYALKY~ENES

This invention relates to halogenated poly-alkylenes whose halo~ens have been partially or totally replaced by ester groups and to the use thereof as cold flow pour depressants in middle distillate fuels, In storage and use of heavy oils, such as lubricating oils, proklems associated with pour point have long been in existence and have been recognized in the art.
The pour point of an oil is defined as the lowest temperature at which the oll will pour or Elow when chilled without disturbance under specified condition.s.
In the past, it has been discovered that pour-point problems also exist in the storage and use o-E distillate fuel oils, particularly at low temperatures. Pour-point problems arise through the formation of solid or semi-~solid waxy particles within an oil composi-tion. For example, in the storage o~ furnace oils or diesel oils during the winter months -temperatures may decrease to a point as low as -26 to ~40C. The decreased temperatures oEten cause crystalli~ation and solidification of wax inthe dis-tillate fuel oil.
Chlorinated polye-thylenes and ethylene vinyl ester type copolymers have been employed as cold flow improvers for hydrocarbon fuels.
The following paten-~ illustrates chlorinated polyethylenes used as cold flow improvers:
U.S.P. 3,337,313 ~i .~ .
` :~ h ~L2~

-2~

U.S.P. 3,04~,479 U.S.P, 3,093,623 U.S.P. 3,131,168 Often both types do not function equally in the ; .
same fuel. One type may ~e effective in one type of fuel while the other may be effective in another type oE fuel.
We have now discovered ester-containing!
polyalkylenes prepared by partially or totally replacing the halo groups of the halopolyalkylenes with e~ter groupsO
We have now'discovered that these ester-containing halopol~alkylenes are o~ten effective as pour depressants or improvè cold 1Ow in those ~uels where the original halopolyalkylenes are not. Thus~ the compositions of this invention broaden the effectiveness of halopoly-alkylenes in such fuel.
The starting compositions of this invention are oil soluble chlorine-containing low molecular weight polyalkylenes which are essentially ree of crosslinking and prefera~ly have a.chlorine content of not more than about 35~ by weight. Polyal~ylenes include polyethylenes and copolymers of ethylene with mono-olefinic hydrocarbons having, for example, 3-20 carbon atoms. The,copolymers pre~erably'have a-t least 50 mole percent ethylene.
The starting chlorine-containing polymers o~
this invention maybe advantageously prepared from non-chlorina-ted ethylene polymers of low molecular weight but have an average molecular weight of.at least about 1,000.
They advantageously have average molecular weights in the range of a~ou-t 1,000-12,000 and preferably, for the purposes of this invention, about 1,000-7,000. Thay are chlorinated to a chlorine content of not more than about 40% by weight, and the resulting chlorine-containing polymers therefore have average molecular weights oE about 1,000-16,000 and preferably about 1,000-9,500.

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Too high'arl average molecular weiyht in the polymer may adversely affec-t its.solubility i.n the fuel oil. Therefore, polymers with very high molecular weiyhts, such as -those from a Ziegler process, are not considered suitable for use in this inven-tion in fuel oil.
The average molecular weigh-ts of the above polymers may conveniently be.determined by means of an ebulioscope or an osmome-ter. Ano-ther method is by means of the in-trinsic viscosity of the polymer ~D-1601~to-T in decalin solvent at 135C).
As sta-ted above, the polymer.or copolymer includes both polyethylene and copolymers of ethylene with mono-olefinic hydrocarbons having 3-~0 carbon atoms with the copolymer having at least 50 mole percent e-thylene.
Advantageously,:the polyethylene tprior to chlorination) has a brarlch index (number of substituent groups per 100 carbon atoms) of not more than about 5. Advantageously, the copolymer is one of ethylene with propylene having (prior to chlorination) a branch index or a-t least 6 and preferably abou-t 6-20. A very advantageous polyethylene is one having a branch index of abou-t 2-3 and a molecular weigh-t of about 2,000. A very advantageous copolymer of ethylene and propylene is one having a branch index of about 10-14 and an average molecular weight of about 1,800.
When the ethylene polymers are chlorinated, na-turally the branch index is increased. However, in iden-tifying the chlorine-containing polymer i-t has been found more convenient to describe the chlorine content of the new polymer in terms o weight percent.
For purposes of this invention, the ethylene polymers described herein have little, if any~ crosslinking;
although, as described above, they include branched polymers.
These polymers may be dessribed as being essen-tially free of crosslinking.

i --4~

The present invention covers po~yalkylene polymers or copolymers containing halogen in the amount of 0-35~
and ester groups, the bond between the carbon atoms of -the poly~lkylene and the ester groups being represented by the formula o O - C - R
C -- C -- C --~1 wherein R is alkyl, alkenyl, cycloalkyl, aryl, aralkyl, .alkaryl, R containing 1-30 carbon atoms, the polyalkylene being essentially free of cross-linking. The polyalkylene polymers or copolymers are prepared by reacting an halogena-ted essen-tially linear polyalkylene having a halogen conten-t of 1 up to 40% and a molecular weight of 1000 - 16,000 wi-th a salt of a carboxylic acid of formula RCOOs~l wherein R is as indicated hereinabove and replacing the halogen a-toms wholly or partially with ester groups.
According to one embodiment of the invention, the polyalkylene is linear pol~ethylene substituted by halogen and ester groups.
Accordiny to-the preferred embodiment of the inven-tion, the halogen is chlorine.
According to a specific embodimen-t of the invention, linear polyethylene of molecular weigh-t about 1500 to 3000, with a chlorine cont~nt from about 1 to 30% base.d on weight of polyethylene is used and the ester content is from about 5 to 200~ based on weight of polye-thylene.
The ester groups are from an organic carboxylic acid which is acetic, propionic, butyric, valeric, hexanoic, hep-tanoic, octanoic, lauric, palmitic, stearic, oleic, benzoic or substituted benzoi.c.

,~? ., s The inven-tion also covers the process of preparing the polyalkylene contc~ning ester groups with 0-35~ halogen content which consis-ts of reacting a chlorina-ted polyalkylene polymer or copolymer of molecular weigh-t 1000 - 16,000 with ca salt of a carboxylic acid in a solvent system which pro-vides a-t least partial solubility of said halogenated polyalkylene and the salt of said carboxylic acid.
The invention also covers fuel oil compositions containing a sufficient amount oE the polyalkylene polymers or copolymers substituted by ester groups and 0-35% halogen `atoms to be effec-tive as a pour depressant.

.A~ i`' / , The chlorine-containin~ ethylene polymers usable in accordance with this invention are oil soluble.
Generall.y, this means tha-t -they are completely soluble in distillate fuel oils in concentrations of at least about 10% by weigh~ (slight hazé is permissable~ at room temperature (25C~.
However, it is not always necessary that the non-chlorinated polymers possess good oil solubili-ty.
To illustratel a polyethylene having a lower order of oil solubility, a crystallinity of about 60-70, a branch index of abou-t 2-3, and an average molecular weight of about 2,00~ has been chlorinated to produce a chlorine-containing polymers having good oil solubility, together with exceptional pour-point depressant properties.
Suitable polyethylene for chlorination are advantageously products or by-products from the peroxide catalyzed polymerization of ethylene. Polymerization reactions using peroxide ca-talysts are well known in the art and any o these may, for example, be used to produce the desired pour-point depressor of this invention. The low molecular weight polyethylene by-products are usually oily liquid hydrocarbon mixtures, hydrocarbon greases, or hydrocarbon waxes obtained in small quantities in the mass polymerizatio~ of ethylene at elevated temperatures and pressures using a ~ree radical poly-merizakion catalyst, and such by-products rom poly-merization catalyzed by the presence o~ peroxides (or oxygen which form~ peroxides) are particularly suitable. Another example o a product which may be used is the homopolymer by-produc-t described by J. W.
Ragsdale, U.S. 2,863,850 paten-ted December 9, 1958.
Other such products are well known in the art.

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The copolymer of ethylene with a mono-oleEinic hydrocaxbon having from about 3-20 carbon a-toms has at least 50 mole percen-t ethylene. The mono-olefinic hydrocarbon includes propylene, butylenes, pentylenes, hexylenes, and up to 20 carbons, and mixtures thereof. Preferably, -the mono-olefinic hydrocarbon is propylene. The copolymers are prepared by methods known in the ar-t. Advantageously, the copolymer of ethylene with propylene is prepared by subjecting the combination to polymerization by peroxide catalyst, or a tetraphenyl tin-aluminum chloride-vanadium tetrachloride catalyst system or a te-tra-alkyl lead-vanadium tetrachloride catalyst system.
Usable polymers for chlorina-tion in accordance herewith may also be ob-tained by extrac-tion of low molecular weight polymers having branch indexes hereinbefore defined.
Extraction may be accomplished using a solvent or a solvent-antisolvent. The extracted polymer is usable if it falls within the definition of the polymers of this inven-tion as to characteristics~ Such extracted fraction usually has a higher branch index and a lower intrinsic viscosity than the starting material, as well as a higher concentra-tion oE total solubility in dis-tillate fuels and a lower crystallinity. Examples of suitable solvents are the low molecular weight hydrocarbons such as bu-tane, pentane, hexane, heptane, etc., and example of antisolvents, usable therewith, are the low molecular weight alcohols such as methanolr ethyl alcohol, isopropyl alcohol, n-butanol, etc. Naphtha is a particularly advantageous solvent because it does not require the use of an antisolvent.
However, because polymers having the desired characteristics are available commercially and because such polymers can be "tailor-made" to have the desired characteristics, it is particularly preferred tc use such polymers which do no-t need prior extraction. Extraction adds an expensive s-tep to preparation of the polymers.

., Such polymers Eor chlorination as described above are well known in the ar-t ana are readily available con~ercially. Many of the usable polymers for chlorina-tion are obtained as by-produc-ts from commercial polymerization processes as undesirable low molecular weight ma-terials and because of their availability and economic attractiveness such by-produc-t polymers are advantageous for use herein.
The chlorination of these polymers produces chlorine subs-ti~uen-ts on the polymer chain. These chlorine substituents increase the pour-point depressant properties of the polymer ! A preferred me-thod of prep~ring the chlorine-containing e-thylene polymer oE this invention (and thereby adding the chlorine substituents on the polymer chain) is carried out by treating the above-defined ethylene polymer with chlorine under sui-table reac-tion conditions to produce the chlorinated ethy~ene polymer.
This process is carried ou-t until the desired chlorine content of the resulting polymer is reachedO Preferably, this conten-t is not more than about 35% by weight of the polymer. Increased amounts o~ chlorine tend to lessen the pour-point properties of the polymer and therefore are not preEerred.
The chlorination may be carried out by one oE
several procedures, In one process, chlorine is bubbled through the molten polymer usually under temperature conditions of at least 65.5C and advantageously between 65 and 205C. A second process is carried:out by bubbling chlorine through the polymer suspended in an.inert solvent, such as carbon tetrachloride (and other chlorinated methanes, ethanes, and the li]~e) under temperature conditions o~ at leas-t 24C. The rate of reaction may be accelerated b~ using an actinis light source~ A third process is carried out by bubbling chlorine through an aqueous suspension of -the polymer. The first two proc~sses are preferred since it is believed that in their use the chlorine contacts a greater portion of-the inner polymer chain.

9L9 ~)0 _9 _ ~t is -to be understood that the chlorine addition includes the use of known chlorina-ting compounds such as sulfuryl chloride, oxalyl chloride, phosgene, and the like.
It is fur-ther believed, but again not known absolutely, that the chlorina-tion of the ethylene polymer produces the chlorine-containing polymer having the chlorine atoms wi-th such a distribution on the polymer chain as to provide exceptional pour-point depressant properties in the polymer.
The ~hlorination i5 carried out to produce a chlorine-containing polymer having preferab~y less than about 35% chlorine by weight. More preferable and op-timum chlorine contents are dependent somewhat on the par-ticular polymer being ¢hlorinated. To illustrate, a polyeth~lene having a branch index of no-t more than about 5 and a molecular weight of about 1,500-2,500 is preferably chlorinated to a chlorine content of about 10-30% by weigh-t. More optimum pour-point depressant properties for this polymer result when it has an average molecular weight of about 2,000, a branch index of about 2-3, and a chlorine content of about 16-23% by weight. Another illustration is a copolymer of ethylene and propylene having a branch index o~ about 6-20, an average molecular weight oE about 1,500-2,000, and a chlorine con-tent of about 4-13 by weigh-t. More optimum pour-point depressant properties are obtained when this polymer has a branch index of about 10-14; an average molecular weight of about 1,800, and a chlorine content of about 8-11% by weight. More exact values Eor these ranges are dependent on the particular fuel oil being utilized.
We have discovered that the halopolyalkylenes can be converted to ester-containing halopolyalkylenes by replacing the halo- ~roups with carboxylgroup so as i ~,~
~...

~2~ 3()~

to yield ester groups O .
Cl O ~-C-R
-C -C - C- ~ R C O M~ C-l - C ~ ~ M ~ Cl ~ H

where R is a hydrocarbon group, for example alkyl, alkenyl, cycloalkyl, aryl, aralkyl, alkaryl, etc., where R has from 1 to 30 carbons.
Suitable carboxylic acids include the following:
acetic, propionic, butyric, valeric, hexanoic, heptanoic, oc-tanoic r lauric, palmitic, s-tearic, oleic, benzoic, substituted benzoic acid, olefinic acids.
The preferred carboxylic acids are alkane-carboxylic acids having from 1-30 carbon atoms but preferably from 1-18 carbon atoms.
In practice, the carbo~ylic acids are reacted in salk forms such as sodium, potassium,etc., salts.
In the compositions of this invention, at least about 1~ of the halogens are replaced, such as from abou-t 1 to lnO% of the halogens replaced, for example fxom about 10 to 80% of the halogens replaced, but preferably from about 15 to 75~
Where all chlorines are not removed the structure of the product is a combination of chlorinated polye-thylene and ethylene vinyl ester copolymer in the same molecule.
In addition, there is olefinic unsatura-tion due to elimina-tion oE IICl. NMR analysis gîves a quantitive determination of the structure since it de-termines the ratio of chlorine to ester to olefin because the adjacent hydroyens to those structural groups are well separated in the NMR. The products contain the following groups:

-11~

Cl o - C - R ~ I
-- C -- 1 -- C -- . . , ~ C = C --~) '' (~ ' The product has a unique s-tructure of a partially chlorinated e-thylene-vinyl ester copolymer with some olefinic unsaturation in the backbone. In the case of linear polyethylene these materials differ radically from normal EVA structures because the backbone is totally linear while ethylene-vinyl ester copolymers have subs-tantial branching.
~ problem tha-t exists is that the mild basici-ty of sodium carboxyla-tes leads to a certain amount of elimination of HCl from the backbone of the polymer to form internal olefin. This reaction competes with the substi-tution reaction. The forma-tion of internal oleEin is known to be harmful to its cold flow activity and this side reaction must be r; nim; ~ed. This elimination side reaction varies depending on temperature, solvent and structure of tha carboxylate anion. It is difficult to eliminate this reaction completely and as far as cold flow activity is concerned we have to make up in substi-tution what we lose by olefin formationO In general the ratio of substitution to elimination ranges from 3/1 to 6/1.
The conversion of chlorinated polye-thylene to a chlorinated ethylene-vinyl ester type copolymer or a halo~en-free product is not a simple task because the sodium salts of carboxylic acids are not soluble in the common nonpolar solven~s that dissolve chlorinated polyethylene.
This incompatibillty problem can be handled in three ways.

49~

1. The reaction can be carried out in a nonpolar solvent in the presence oE,a crown e-ther (such as 18-crown 6) which essen-tially solubilizes the me-tal ion carboxyla-te in-the organic medium and allows for a homogeneous reaction.
2. The reaction can also be carried out in the presence of a phase transfer catalyst system. This entails dissolving the sodium carboxylate and an oil-water soluble quaternary ammonium compound in water and conducting a two phase reaction with the chlorinated polyekhylene dissolved in a nonpolar organic solvent.
-The reaction proceeds because the quaternary ammonium salt transfers the carboxylate anion as part o~ its own structure to -the organic phase so that the actual reaction proceeds homogeneously.

3. The reaction can be carried ou-t in a solvent mixture where there is partial solubility of both the ¢hlorina-ted polymer and the salt of the organic acid.
The first two reaction methods are less economical because of the high cos-t of crown e-thers and quaternary ammonium compounds. ~.ethod 9 is the most economical]y commercial.
We have found that blends of alcohols, and blends of alcohols and ketones ("Ethyl Cellosolve"/methyl isobutyl ke-tone, methyl carbitol/diisobu-tyl ketone) allow us to conduct the displacement reaction in an effective manner.
The following examples are presented for purposes of illustration and not of limit~tion. The chlorinated polyethylene employed herein is a chlorina-ted linear polyethylene having a molecular weight of about 2000 and a weight % chlorine content o about 24%.

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Example 1 A mixture oE 20 gms chlorinated linear poly-ethylene, 24 gms of potassium ace-tate (.153 mole) and 2 gms (~00756 mole) of 18 crown-6(1,4,7,10,13,16,-hexa-oxacyclo-oc-tadecane) was stirred in 30g of Solvent 14.
The -total was heated at 130C for 24 hours. The reac-tion mix-ture was cooled slightly and fil-tered. Evaporation of the solvent lef-t a waxy residue. An infrared spectrum of the residue showed strong carbonyl absorption a-t 1740 cm~l. The proton NMR showed the following:
(CC14 solvent, TMS in-ternal standard) 1.'24 ~(mul-tiplet, CH2~
1.96d~(sing1et, O-C-CH3) 3.58 ~(singlet, crown ether CH2's) 3.82 (CHCl) 4.77df(CH-O-C-CH3) 5.32 of(olefinic CI12).
The following is the analytical determination of the extent of reaction by integra-tion of the respective CH absorp-tions.
Cl~ ~ ester, % Olefin = 15:70:15.
Example 2 A mixture of 20.0g chlorinated linear poly-ethylene, 17.0g (0.207 mole) of sodium acetate, 100 ml of methyl isobutyl ketone, 10 ml o;E water, and 2.4g (.0066 mole) of hexadecyl-trime-thylammonium bromide was stirred and heated in a stainless steel reactor at 125C
for 3 days. The reac-tion mixture was then cooled and 250 ml of methanol was added and the mixture stirred for 15 minutes. The methanol portion was decanted and this washing process was repeated three times. The residue was then transferred to a 400 ml beaker and dissolved in cyclohexane and toluene by heating and stirring. The mixture was filtered and evapora-tion of the solvent rom a sample of the filtrate left a waxy residue. The IR
and NMR spectra had characteristic absorptions similar to those of the previous example and the following relative analysis was determined from the NMR spectrum~
% Cl: % Ester: ~ Olefin - 51:39:10.

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Examp~e 3.
~ 13 gms of lauric acid was dissolved in 90 mls of'~utyl Cellosolve"and 15 mls of ethylene glycol. To this was added 3~5 gms of sodium methoxide and the mixture was heated -to 120DC until it became clear (forma-tion of sodium laurate). 20 gms oE chlorinated linear poly-ethylene was added and the reaction was stirred vigorously at 145C for 22 hours. The reac-tion was cooled and a large excess of methanol was added to precipitate the polymer. The polymer was washed with met.hanol and then redissolved in.cyclohexane. NMR analysis.shows the following results~ % Cl % Ester: ~ Olefin = 54:35:10.
- EXample 4 19 gms of lauric acid was dissolved in 100 mls of methyl.carbitol and 25 mls of diisobutyl ketone. To this was added 5.1 gms of sodium methoxide in order to form the sodium laurate. 20 gms of chlorinated linear polyethylene was added and the reaction was heated at 155~C for 24 hours. The polymer was precipita-ted in methanol, washed and redissolved in cyclohexane. NMR
analysis shows the ra-tio o~ ~ Cl: ~ ~ster: ~ Olefin 45:43:12.
Example 5 Using the same reaction conditions as Example 4, the following acids were used for conversion to thei.r sodium salts and subsequen~ displacement of chlorines ~rom chlorinated polyethylene (a) propionic tb) octanoic acid (c) oleic acid (d) s-tearic acid.
The ester-containing chlorine-containing ethylene polymers of this invention are very useful for depressing pour points of :Euel oils. Most hydrocarbon uels yield crystals of solid wa~ as their temperature is lowered below the cloud point. In a usual distillate fuel oil composition containing a pour-point depressant addition agent, the crystals of solid wax do not hinder . ., g~

~15-flow through pumps, Eilters,.screens,.e-tc., even at temperatures well below the pour point of the. base oil, Eor example, dis-tilla-te Euel oil. In such cases the crys-tals are small and therefore do not hinder flow.
However, in some fuel blends the crystals which form are sufficiently large and dense.so tha-t an immobile layer of crystals is formed at the bottom oE storage tanks.
Such crystals of solid wax are not susceptible to treatment by most pour-point depressants tailored for distillate fuels and the crystals can therefore cause severe flow problemsO The flow problems arise when it is attempted to pump the fuel from one location to another.
Pump parts, filters, and~the like tend to become clogged with the crys-tals of solid wax which concen-trate in the fuel oil at the bottom of storage tanks. The polymers of the present invention, when used as pour-point depressants, serve to improve the pumpability of a distillate fuel oil, normally tendiny to produce wax crys-tals of sufficient size and densi-ty (formed even in the presence of conventional pour-point depressant to inhibit pumpability, in addition to lowering the pour point).
The polymers of this invention advan-tageously imp~ove pumpability; for example, a chlorine-containing polyethylene of the above-defined characteristics is very active in modifying the wax crys-tals formed in or precipitated from troublesome fuels normally tending to form large dense crystals at lower temperatures. Although the ~ormation o~ the wax is not actually inhibited when using the polymer additive of.this invention, the wax appears as a vary finely divided ~luffy material which should be pumpable under most conditions.

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~2~90~

The fuel oil composition of this invention comprises a major amount of a dis-tillate fuel oil and as an improved pour-point depressan-t, a small but effective amoun-t of -the above-defined chlorine-containing ethylene polymer. Usually the chlorine- and ester containing polymer is present in an amount ~rom about 0.001 to about

5 weight percent, advan-tageously ~rom about 0.001 to about 0.1 weight percent, and preferably from about 0.005 to about 0.03 weight percen-t. The chlorine- and es-ter-containing polymer may be added directly to the fuel oil or may be formulated in concentrated form ~n a hydrocarbon solven-t such as benzene, toluene, xylene, and the like.
Additional suitable solvents are more specifically described hereinbelow.
The fuel oil is a hydrocarbon oil such as, for example, a diesel fuel, a jet fuel, a heavy industrial residual fuel (e.g. Bunker C), a furnace oil, a hea-ter oil fraction, kerosene, a gas oil, or any other like ligh~ oil. O~ course, any mixtures of distillate oils are also intended. The dis-tillate fuel oil may be virgin and/or cracked petroleum fractions. The distillate fuel oil may advantageously boil in the same ranye of from about 120 to about 400C. The distillate fuel oil may contain or consist of cracked components such as for example, those derived from cycle oils or cycle oil cuts boilin~ heavier than gasoline, usually in the ranye of from about 230 to about 400C and may be derived by catalytic or thermal cracking. High-sulfur-containing and low-sulfur-containing oils such as diesel oils and the like may also be used. The distillate oil may, of course, contain other components such as addition, agents used to perform particular functions, for example, rust inhibitors, corrosion inhibitors, antioxidants, sludge stabilizing compositions, etc.

The preferr~d distillate fuel oils have an initial boiling point in the range of from abou-t 120 to abou-t 246C and an end poin-t in -the range of from about 260 -to about 400C. The dis-tilla-te Euel oil may advantageously have an A.P.I. gravi-ty of about a-t least 30 and a flash point ~Tag closed cup) not lower than about 43C and preferably above about 46C.
The ester-containing chlorine-containing polymers of this invention may, for convenience, be prepared as concentrates as additives for fuels.
Accordingly, the polymer is dissolved in a'suitable organic solven-t therefor in amounts greater than 10% and preferably from about 10% to about 75%. The solvent in such concentrates may conveniently be present in amounts rom about 25-~ to about 90~. The organic solvent preferably boils within the range of from about 38C
to about 372C. The preferred organic solvents are hydrocarbon solven-ts, for example, petroleum fractions such as naph-tha, heater oil, mineral spirits, and the like; aroma-tic hydrocarbons such as benzene, xylene and toluene; paraffinic hydrocarbons such as hexane, pentane, etc. The solvents selected should, of course, be selected with regard to possible beneficial or adverse effects they may have on the ultimate fuel oil composition.
Cold flow activity is determined according to the procedure of ASTM D 97.

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Table 1~
Cold Flow Activity C~undsOil A Oil B Oil C Oil D
ppm0 300 600 800 0 ~00 600 0 -300 ~00 0 600 900 Oom~rcial EU~-5 -15 -~0 -~S ~20 -10 -10 : -5 -~S -40 *Linear Chlorina~ed Polyethyl~ne -5 -10 -10 -10 -~20 - O - B ~25 -15 -15 -5 - 5 -10 .Example 1 -5 -10 -5D -50 Example 3 -S -10 -10 -S0 ~0 -10 --20 -~25 -20 -40 .
E~ample 4 . ~ - 5 - 5 -25 *This linear chlorinated polye-thylene was that employed as a s-tarting material in preparing the chloro-esters of Examples 1, 3 and 4.

; . . Table 2 . .
Cold Filter Plugging Point ~CFPP) IP309/~0*
- . Oil A . Oil B Oil C
, CFPP Blank C -5 ~5 ~10 Compounds PPM 1500 . 1950 1750 Commercial E~A~ 10 -1 ~ 5 Commercial EVA-2 -11.5 -3 . ~ 1 Chlorinated Polye-thylene - 8 . .-~2 ~ 5 Example 5D -14 ~3 - 5.5 Example 5B . . 1~.5 -6 - 8 .
I

.; ~ .

~i f 3~ s o ~

* IP sook of Standards, pp. 309.1-3.09.6. The CFPP is defined as -the highes-t tempera-tuxè ~expressed as a multiple of 1C) at which fuel, when cooled under prescribed conditions, either will not flow through the filter or requires more -than 60 seconds for 20 ml. to pass through.

Irable 3 Low Temperature Flow Test (LTFT)*
.. . Oil A (Cloud - 24.4C) Compound ~ . ~ PPM . LTFT Flow (-27.dC) Commercial ~VA . . 2000 - Fai.l . 2250 Fail Chlorinated Polyethylene 2000 Fail . .2250 Fail Exampl.e 5C 2000 26 seconds Example 1 - . 2250 25 seconds Example 5A . 2250 33 seconds . Oil B ~Cloud -17.~C) . ' LTFT Flow (~21~1C) Commercial EVA 200 Fail 300 Fail 400 38 seconds Chlorinated Polyethylene 200 - Fail . 300 Fail - . . 400 . Fail Example 5C - 200 .Fail 300 . 34 secollds ` 400 - 30 seconds * rrest developed by Exxon Research and Engineering Co. to determine the low.temperature operabiiity of diesel fuels in autodiesel equipment. Diesel fuels passing the test are expected to provide satisfactory operability (free of wax plugging) in autodiesel equipment at fuel temperatures equal to or higher than that of the test.
Low temperature operability of the test fuel at a given j, .... ~
30~

temperature is considered satisfactory iE passage of the fuel -through a prescribed screen ls comple-ted in less -than 60 seconds.

In summary, this invention relates to halogenated polyalkylenes whose ha.logens have been wholly or partially replaced by es~er groups. The preferred polyalkylene is polye-thylene and the preEerred embodiment thereof be.ing a linear polye-thylene.
The polyethylenes have a molecular, weigh-t of from about 1000 to 30,000, such as from about 1500 to 10,000, bu-t preferably from about 1500 to 3000, and a halogen content of f.rom about 1 -to 40, such as from about 5 to 30, but preferably from about 10 to 25.
The percent of halogens replaced with ester groups can vary from about 1 to 100, such as from about 10 to 80, but preferably from about 15 to 75.
The invention also relates to the use o the above compositions as pour depressant or cold flow improvers.
The amount of pour depressant employed based on wgt. of Euel is from about 1 to 2000 ppml such as from about 10 to 1800 ppm, for example from about 50 to 1800 ppm, but preferably about 100 to 1500 ppm.

Claims (15)

The embodiments of the invention in which an exclusive property or privilege is claimed, are defined as follows:

1. A polyalkylene polymer or copolymer containing halogen in the amount of 0-35% and ester groups, the bond between the carbon atoms of the polyalkylene and the ester groups being represented by the formula wherein R is alkyl, alkenyl, cycloalkyl, aryl, aralkyl, alkaryl, R containing 1-30 carbon atoms, said polyalkylene being essentially free of cross-linking, said polyalkylene polymer or copolymer being prepared by reacting an halogenated essentially linear polyalkylene having a halogen content of 1 up to 40% and a molecular weight of 1000 - 16,000 with a salt of a carboxylic acid of formula RCOOH wherein R is as indicated hereinabove and replacing the halogen atoms wholly or partially with said ester groups.

2. The polyalkylene according to claim 1 which contains both halogen and ester groups and which is essentially linear.

3. The polyalkylene of claim 2, which is linear polyethylene.

4. The linear polyethylene of claim 3 wherein the halogen is chlorine.

5. The linear polyethylene of claim 4, wherein the molecular weight is from about 1500 to 3000, the chlorine content is from about 1 to 30% based on weight of polyethylene, and the ester content is from about 5 to 200% based on weight of polyethylene.

6. The polyalkylene according to claim 1 wherein said halogen atoms are completely replaced by ester groups.

7. The polyalkylene of claim 1, which is an ethylene/
propylene copolymer.

8. The polyalkylene of claims 1, 2 or 3 wherein the ester groups are from an organic carboxylic acid which is acetic, propionic, butyric, valeric, hexanoic, heptanoic, octanoic, lauric, palmitic, stearic, oleic, benzoic or substituted benzoic.

9. The polyalkylene according to claim 3 which is prepared from a chlorinated linear polyethylene of molecular weight 2000 and chlorine content 24% by partial replacement of the chlorine atoms with an ester group, said ester group being derived from acetic, lauric, propionic, oleic, octanoic or stearic acid.

10. The polyethylene containing chlorine and ester groups according to claim 4 which is prepared from a chlorinated linear polyethylene of 10-25% halogen content and 15-75%
of the chlorine is replaced by ester groups.

11. The process of preparing the polyalkylene of claim 1, which consists of reacting a chlorinated polyalkylene polymer or copolymer of molecular weight 1000 - 16,000 with a salt of a carboxylic acid in a solvent system which provides at least partial solubility of said halogenated polyalkylene and the salt of said carboxylic acid.

12. The process according to claim 11 which consists of reacting a chlorinated polyalkylene polymer or copolymer of molecular weight between 1000 and 16,000 with a salt of a carboxylic acid in a nonpolar solvent in the presence of a crown ether.

13. The process of preparing a polyalkylene according to claim 1 which consists of reacting said halogenated poly-alkylene and said salt of said carboxylic acid in the presence of a phase transfer catalyst system.

14. A fuel oil containing a sufficient amount of the polyalkylene polymer or copolymer according to claim 1 to be effective as a pour depressant.

15. The fuel oil according to claim 14 which contains 0.001 - 5% of said polyalkylene.