NO317935B1 - Waxy compositions with floating point reducing agents - Google Patents

Description

The present invention relates to waxy liquid compositions, a method for reducing the pour point of a waxy liquid which has an initial pour point of at least 4°C, and the use of a pour point reducing agent to reduce the pour point of such a liquid.

Various types of distillate fuel oils such as diesel fuel, various lubricating viscosity oils, automatic transmission fluids, hydraulic oil, home heating oils and crude oils and fractions thereof require the use of pour point depressants to allow them to flow freely at lower temperatures. Often the kerosene is included in such oils as a wax solvent, especially that present in distillate fuel oils. However, the need for kerosene for use in jet fuel has caused the amount of kerosene present in distillate fuel oils to be reduced in recent years. This in turn has required the addition of wax crystal modifiers to correct the deficiency of the kerosene. However, the requirement for pour point lowering additives in crude oils may be even more important, as the addition of the 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) discloses alkylphenol-formaldehyde condensate additives for improving the low temperature flow properties of hydrocarbon oils . The polymer composition has an average molecular weight of at least about 3,000 and a molecular weight distribution of about 1.5; in the alkylated phenol reactant, the alkyl groups are predominantly linear and have between 6 and 50 carbon atoms, and have an average number of carbon atoms of between about 12 and 26; and not more than about 10 mole percent of the alkyl groups on the alkylated phenol have fewer than 12 carbon atoms, and not more than about 10 mole percent of the alkyl groups on the alkylated phenol have more than 26 carbon atoms.

U.S. patent 4,565,460, Dorer, Jr., et 1, Jan. 14,1986, (and U.S. patents 4,559,155, Dec. 17,1985,4,565,550, Jan. 21,1986,4,575,526, March 11, 1986 and 4,613,342, Sept. 23,1986, divisions thereof), describe additive combinations for improving the cold flow properties of hydrocarbon fuel compositions. The composition comprises a pour point depressant which may be a hydrocarbyl substituted phenol of the formula (R<*>)a Ar_(OH)b where R<*> is a hydrocarbyl group selected from the group comprising hydrocarbyl groups having from about 8 to about 39 carbon atoms and polymers with at least 30 carbon atoms. Ar is an aromatic moiety which may comprise linked polynuclear aromatic moieties represented by the general formula ar-

(-Lng-ar-) w(Q)mw where w is an integer from 1 to about 20. Each Lng is a bridging bond of the type comprising alkylene bonds (eg -CH 2 -among others).

EP-311 452, Martella, describes a process for the preparation of alkylphenol-formaldehyde condensates to improve the low temperature properties of hydrocarbon oils. The alkyl groups have an average number of carbon atoms of between about 12 and 26, although comparative examples use a material with an alkyl group having 30 carbons. The alkyl chain length of 12 to 26 carbon atoms is described as being critical, and materials with higher alkyl chain length are said here to be ineffective in reducing the pour point.

SUMMARY OF THE INVENTION

The present invention relates to a waxy composition comprising:

a) a waxy liquid having an initial pour point of at least 4°C, and

b) an amount sufficient to reduce the pour point of the waxy liquid by at least 0.6°C, the amount being at least 50 ppm, of a pour point depressant comprising the reaction product; i) a hydrocarbyl substituted phenol having a number average of more than 30 carbon atoms i

the hydrocarbyl substituent and ii) an aldehyde of 1 to 12 carbon atoms or a source thereof.

The present invention further provides a method for reducing the pour point of a waxy (e.g. paraffin-containing) liquid which has an initial pour point of at least 4°C which comprises adding to said liquid a pour point reducing amount of a pour point reducing agent which comprises the reaction product of i ) a hydrocarbyl substituted phenol with a number average of more than 30 carbon atoms in the hydrocarbyl substituent and ii) an aldehyde with 1 to 12 carbon atoms or a source thereof.

Finally, the present invention includes the use of a pour point depressant comprising the reaction product of i) a hydrocarbyl substituted phenol with a number average of more than 30 carbon atoms in the hydrocarbyl substituent and ii) an aldehyde of 1 to 12 carbon atoms, or a source thereof, to reduce the pour point to a waxy liquid having an initial pour point of at least 4°C.

DETAILED DESCRIPTION OF THE INVENTION

The first aspect of the present invention relates to a composition comprising a pour point depressant comprising the reaction product (i) a hydrocarbyl substituted phenol having a number average of more than 30 carbon atoms in the hydrocarbyl substituent, and (ii) an aldehyde having 1 to 12, preferably 1 to 4, carbon atoms, or a source of this.

Hydrocarbyl-substituted phenols are known materials, which also applies to their production method. When the term "phenol" is used herein, it is to be understood that the term is not generally intended to limit the aromatic group in the phenol to benzene (unless the context so indicates, such as in the examples), although benzene may be the preferred aromatic group . Rather, the term is intended to be understood in its broader sense to include hydroxyaromatic compounds in general, for example substituted phenols, hydroxynaphthalenes and the like. The aromatic group of a "phenol" can thus be mononuclearly or polynuclearly substituted, and can include other types of aromatic groups in addition.

Thus, the aromatic group of the hydroxyaromatic compound may be a simple aromatic nucleus such as a benzene nucleus, a pyridine nucleus, a thiophene nucleus, a 1,2,3,4-tetrahydronaphthalene nucleus, etc., or a polynuclear aromatic moiety. Such polynuclear parts may be of the fused type; i.e. where pairs of aromatic nuclei making up the aromatic group share two points, such as found in naphthalene, anthracene and azanaphthalenes etc. Polynuclear aromatic moieties can also be of the linked type where at least two nuclei (either mono- or polynuclear) are linked through a bridge bond with each other. Such bridging bonds may be selected from the group consisting of carbon-to-carbon single bonds between aromatic nuclei, ether bonds, keto bonds, sulfide bonds, polysulfide bonds with 2 to 6 sulfur atoms, sulfinyl bonds, sulfonyl bonds, methylene bonds, alkylene bonds, di-(lower alkyl)methylene bonds, lower alkylene ether bonds, alkylene keto bonds , lower alkylene sulfur bonds, lower alkylene polysulfide bonds with 2 to 6 carbon atoms, amino bonds, polyamino bonds and mixtures of such divalent bridging bonds. In certain cases, more than one bridging bond may be present in the aromatic group between aromatic cores. For example, a fluorene nucleus with two benzene nuclei is bonded by both a methylene bond and a covalent bond. Normally, the aromatic group will only contain carbon atoms in the aromatic nucleus per se, although other non-aromatic substitutions, such as especially short-chain alkyl substitution, may be present. For example, methyl, ethyl, propyl and t-butyl groups may be present on the aromatic groups, although such groups are not explicitly represented in the structures shown here.

Specific examples of simple ring aromatic groups are the following

etc., where Me is methyl, Et is ethyl or ethylene, and Pr is n-propyl. Specific examples of fused aromatic moieties are:

etc.

When the aromatic moiety is a bonded polynuclear aromatic moiety, it can be represented by the general formula

where w is an integer from 1 to about 20, each ar is a single ring or a fused ring aromatic core of 4 to about 12 carbon atoms and each L is independently selected from the group consisting of carbon-to-carbon single bonds between the ar nucleus, ether bonds (f .e.g. -0-), keto bonds (e.g. -C(=0)-), sulfide bonds (e.g. -S-), polysulfide bonds with 2 to 6 sulfur atoms (e.g. -S-2^ ), sulfinyl bonds (e.g. -S(O)-), sulfonyl bonds (e.g. -S(0)2-), lower alkylene bonds (e.g. -CH2-, -CH2-CH2-, - CH2-CHR °-), mono(lower alkyl)-methylene bonds (e.g. -CHR<0->)- di(lower alkyl)-emtethylene bonds (e.g. -CR°2-), lower alkylene ether bonds (e.g. -CH20- , -CH2O CH2-, -CH2-CH20-, -CH2-CH2OCH2CH2-, -CH2CHOCH2CH-, -CHR°-0 -CHR°-0-CHR°-, lower alkylene sulphide bonds (e.g. where one or more -0- 's in the lower alkylene ether bonds are replaced by an S atom), lower alkylene polysulfide bonds (e.g. where one or more -O- is replaced by a -S-2-6 group), amino bonds (e.g. -CH2NCH2-, -alk-N-, where alk is lower alkylene, etc.), polyamino bonds (e.g. - N(alkN)i-io, where the unsaturated free N-valences are occupied by H atoms or R°- groups), bonds derived from oxo- or keto-carboxylic acids (e.g.)

where each of R<1>, R<2> and R3 is independently hydrocarbyl, preferably alkyl or alkenyl, most preferably lower alkyl or H, R<6> is H or an alkyl group and x is an integer in the range from 0 to about 8 and mixtures of such bridging bonds (each R° is a lower alkyl group).

Specific examples of connected groups are:

Generally, all of these aromatic groups have no substituents except those specifically indicated. From cost groups, 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 simple benzene ring.

This first reactant is a hydroxyaromatic compound, i.e. a compound in which at least one hydroxy group is directly connected 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 part can have while simultaneously maintaining at least one, and preferably at least two, positions, at least two of which are preferably adjacent (ortho) to a hydroxy group, which suitable for further reaction by condensation with aldehydes (described in detail below). Thus, most of the molecules in the reactant will have at least two unsubstituted positions. Suitable materials may then include hydrocarbyl substituted catechols, resorcinols, hydroquinones and even pyrogallols and phloroglucinols. Most commonly, however, each aromatic nucleus will carry a hydroxyl group and in a preferred case when a hydrocarbyl-substituted phenol is used, the material will contain a benzene nucleus and a hydroxyl group. Naturally, a small fraction of the aromatic reactant molecules may contain zero hydroxyl substituents. For example, a minor amount of non-hydroxy materials may be present as an impurity. However, this is not outside the scope of the invention as long as the starting material functionally typically contains at least one hydroxyl group per molecule.

The hydroxyaromatic reagent is similarly characterized in that it is hydrocarbyl substituted. The term "hydrocarbyl substituent" or "hydrocarbyl group" as used herein is in its usual meaning well known to those skilled in the art. Specifically, it refers to a group which has a carbon atom directly connected to the rest of the molecule and which is mainly hydrocarbon in character. Examples of hydrocarbyl groups include: 1) Hydrocarbon substituents, i.e. aliphatic (e.g. alkyl or alkenyl), alicyclic (e.g. cycloalkyl, cycloalkenyl) substituents and aromatic-, aliphatic- and alicyclic-substituted aromatic substituents as well as cyclic substituents in which the ring is completed through another part of the molecule (eg two substituents together form an alicyclic radical); 2) substituted hydrocarbon substituents, i.e. substituents containing non-hydrocarbon groups which within the scope of the invention do not change the mainly hydrocarbon substituted (e.g. halo (especially chlorine and fluorine), hydroxy, alkoxy, mercapto, alkylmercapto, nitro, nitroso and sulfoxy ); 3) heterosubstituents, i.e. substituents which, although they have a mainly hydrocarbon character within the scope of the invention, contain something other than carbon in a ring or chain which is otherwise composed of carbon atoms. Heteroatoms include sulfur, oxygen, nitrogen and include substituents such as pyridyl, furyl, thienyl and imidazolyl. In general, no more than two, preferably no more than one, Me hydrocarbon substituent will be present for every tenth carbon atom 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 more than 30 carbon atoms or, if the alkyl group is a mixture of alkyl groups, the mixture will contain an average of more than 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 contain a mixture of alkyl groups which can vary in length from one particular molecule to another. While a fraction of the molecules may contain an alkyl group with fewer than 30 carbon atoms, the composition as a whole will normally be characterized by having an alkyl substitution of more than 30 carbon atoms in length. The alkyl groups may in any case be derived from either linear or branched olefin reactants; linear are sometimes preferred, although the longer chained materials tend to increase the branching proportion. A certain amount of branching appears to be introduced via a rearrangement mechanism during the alkylation process as well.

In a preferred embodiment, the hydrocarbyl groups used comprise a mixture of alkyl lengths of substantially more than 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 by having approximately the following chain length distribution:

The hydrocarbyl substituent thus contains a number average of more than 30 carbon atoms. Such substituents are preferably alkyl groups where the average number of carbon atoms in the alkyl chain is 31-40, more preferably 32-38.

The hydrocarbyl group may 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 often an aliphatic group (or a mixture of such groups) prepared 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 part of the alkyl group or groups are preferably straight chains, i.e. mainly linear. It is believed that these properties are preferred to allow the chain to interact better with the chain structure of the wax-forming hydrocarbons. However, in many cases a methyl branching has been observed at the point of attachment of the alkyl chain to the aromatic ring, even when an α-olefin is used. This is considered to be within the meaning of straight chain or linear alkyl groups. Likewise, some of the alkyl groups may in some cases 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 used are 1-mono-olefins such as homopolymers of ethylene. These aliphatic hydrocarbyl groups may also be derived from halogenated (eg, chlorinated or brominated) analogs of such homo- or interpolymers. However, such groups may be derived from other sources, such as monomeric high molecular weight alkenes (e.g. 1-tetracontene) and chlorinated analogues and hydrochlorinated analogues thereof, sulphated petroleum fractions, especially paraffin waxes and cracked and chlorinated analogues and hydrochlorinated analogues thereof, white oils, synthetic alkenes such as those produced by the Ziegler-Natta process (eg poly(ethylene) grease) and other sources known to those skilled in the art. Any unsaturation in the hydrocarbyl groups can be reduced or eliminated by hydrogenation according to procedures known in the art. Manufactured by means of, or by the use of, materials which are substantially free of chlorine or other halogens, is sometimes preferred for environmental reasons.

In one embodiment, a portion of the hydrocarbyl groups are derived from polybutene. In another embodiment, part of the hydrocarbyl groups are derived from polypropylcn. In a preferred embodiment, the hydrocarbyl group is derived from a mixture of substantially unbranched olefins having chain lengths of substantially 30-36 carbon atoms, as described above.

More than one such hydrocarbyl group may be present, but usually no more than 2 or 3 are present for each aromatic ring in the aromatic group. Typically only 1 hydrocarbyl group is present per aromatic part, especially where the hydrocarbyl-substituted phenol is based on a single benzene ring.

The attachment of a hydrocarbyl group to the aromatic portion of the first reactant of the present invention can be accomplished by a number of techniques well known to those skilled in the art. A particularly suitable technique is the Friedel-Crafts reaction, in which an olefin (eg, a polymeric olefinic bond) or halogenated or hydrohalogenated analogues thereof is reacted with a phenol in the presence of a Lewis acid catalyst. Procedures and conditions for carrying out such reactions are well known to the person skilled in the art. See, for example, the discussion in the article entitled "Alkylation of Phenols" in the "Kirk-Othmer Encyclopedia of Chemical Technology", Third Edition, Vol 2. Pages 65-66, Interscience Publishers, a division of John Wiley and Company, N.Y. Other equally suitable and expedient techniques for attaching the hydrocarbon-based group to the aromatic moiety will be apparent to those skilled in the art.

The pour point lowering material according to the present invention, which has an average alkyl chain length of more than 30 carbon atoms, is 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), i.e. natural sources and partially refined oils, including partially processed petroleum derived oils. The suitable oils are those having an initial (ie unmodified or prior to treatment with a pour point depressant) pour point of at least 4°C, preferably at least 10°C, or more preferably 16°C. The use of the present materials is particularly valuable in those crude oils which are difficult to process in other ways. For example, they are particularly useful in oils (crude oils and oil fractions such as those described above) which have a wax content of more than 5% by weight, preferably more than 10% by weight as measured according to UOP-46-85 (procedure ifig. UOP, In., 'Taraffin wax content of petroleum oils and asphalts").

(Wax-containing materials are sometimes referred to as paraffin-containing materials, where paraffin is roughly equivalent to wax, and especially for petroleum waxes. The present invention is not particularly limited to any particular type of wax that can cause the pour point phenomenon in a given liquid. The paraffin wax, microcrystalline waxes and others grow, are thus encompassed It is understood that in many important materials, such as

petroleum oils, paraffin wax can be particularly important.) The pour point reducing materials are further useful in oils with a large high-boiling fraction, i.e. in which the fraction boiling between 271°C and 538°C (i.e. around Cl 5 and above) comprises at least 25 %, preferably more than 30%, more preferably at least 35% of the oil (excluding any fractions with 7 or fewer carbon atoms). Among high-boiling oils, they are more particularly useful if more than 10%, preferably more than 20%, more preferably more than 30%, of the high-boiling (271538°C) fractions boil between 399°C and 538°C (ie about C25 and higher), according to ASTM D 5307-92. Preferably, this high boiling (399-538°C) fraction will comprise at least 10% of the total oil (excluding any fraction of 7 or fewer carbon atoms). The analysis is preferably carried out on storage tank crude oil that is degassed and contains little or no fraction of C4 or lower. They are further useful in materials that have an API gravity greater than 20°C (ASTM D-287-82).

Available pour point reducing materials are in many cases useful for treating oils (e.g. crude oils and fractions thereof) which have an Nw of greater than 18, preferably greater than 20, and more preferably greater than 22. Here Nw is the weight average number carbon atoms of the molecules in the oil, defined by

where Bn represents the weight percentage of the crude boiling fraction of the oil containing the alkane CnH2n+2 and n is the carbon number of the corresponding paraffin. These boiling fraction values were determined by ASTM procedure D5307-92. Most preferably, the suitable oils will have the above defined value for Nw, as well as one or more of the above mentioned characteristics such as a pour point above 4°C and/or a wax content of more than 5% (UOP-41-85 procedure ).

The amount of pour point reducing agent used in the oil or in other waxy liquids will be an amount suitable to reduce the pour point thereof by at least 0.6°C, preferably at least 2°C, more preferably 3°C, and even more preferably 6°C . This reduction in pour point can be easily determined by the person skilled in the art using the method according to ASTM D-97. Typically, the amount of pour point reducer 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.

Except in the examples, or where otherwise explicitly indicated, all numerical quantities in the present description specifying amounts of materials, reaction conditions, molecular weights, number of carbon atoms, etc., are intended to be understood as modified by the word "about". Unless otherwise indicated, any chemical substance or composition referred to herein shall be understood to be commercial grade materials which may contain the isomers, by-products, derivatives and other such materials normally understood to be present in commercial grade. However, the amount of each chemical component is present without any eluent or diluting oil that may normally be present in the commercial material unless otherwise indicated. As used herein, the phrase "consisting essentially of" permits the inclusion of substances which do not materially affect the basic and novel characteristics of the composition of the invention.

Example 1

A 12 liter, four-necked, round-necked flask equipped with a thermocouple, nitrogen gas bubble tube (14 l/h, N2), mechanical stirrer, Dean-Stark trap and Friedrich^ condenser is charged with 1901 g (20.2 equivalents) of distilled ( 95%) phenol. The phenol is heated with stirring to 100°C and 62.4 g of Amberlyst 15™ catalyst (from Rohm and Haas) was charged. The mixture was further heated to 150°C and held for 1.5 hours, 9.5 ml of a colorless condensate was collected in the trap. The mixture was held at 150°C while 2150 g of a C3+ α-olefin blend from Chevron was charged over a period of 1.3 hours; then the mixture was held at 150°C for another 0.5 hour. The mixture was cooled to 120°C and filtered through a glass microfiber filter pad to remove the catalyst. The filtrate was stripped at 160°C at 1.5 kPa pressure. The resulting material was again filtered through a micro-fibrous glass filter pad at 120°C to give the product as a liquid which solidified to a waxy solid.

Example 2

The second component which reacts to form the pour point depressant is an aldehyde of 1 to 12 carbon atoms, or a source thereof. Suitable aldehydes have the general formula RC(0)H, where R is preferably hydrogen or a hydrocarbyl group as described above, although R may comprise other functional groups which do not interfere with the condensation reaction (described below) of the aldehyde with the hydroxyaromatic compound. This aldehyde preferably contains 1 to 12 carbon atoms, more preferably 1 to 4 carbon atoms and even more preferably 1 or 2 carbon atoms. Such aldehydes include formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, isobutyraldehyde, pentanaldehyde, 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. Parafomaldehyde can be considered a reactive equivalent of, or a source for, an aldehyde. Other reactive equivalents may include hydrates or cyclic rimers of aldehydes.

The hydrocarbylphenol and the aldehyde are generally reacted in relative amounts ranging from phenolaldehyde molar ratios of 2:1 to 1:1.5. Preferably, roughly equal molar amounts will be used up to a 30% molar excess of the aldehyde (calculated based on the aldehyde monomer). Preferably, the amount of aldehyde is 5 to 20, more preferably 8 to 15, percent greater than the hydrocarbylphenol, on a molar basis. The components were reacted under conditions leading to oligomer or polymer formation. The molecular weight of the product will depend on properties including the equivalent ratios of reactants, the temperature and time of the reaction and the impurities present. The product may have from 2 to 100 aromatic units (ie the substituted aromatic phenolic monomeric units) present ("repeating") in its chain, preferably 3 to 70 such units, more preferably 4 to 150, 30 or 14 units. When the hydrocarbylphenol is specifically an alkylphenol with 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, even more preferably 3,000 to 6,000. The molecular weight of the materials, based on a hydrocarbyl substituent length of about 34 carbon atoms, will be proportionally somewhat higher.

The hydrocarbylphenol and the aldehyde were reacted by mixing the alkylphenol and the aldehyde in a suitable amount of diluent oil or any other solvent such as an aromatic solvent, e.g. xylene in the presence of an acid such as sulfuric acid, a sulfonic acid such as an alkylphenylsulfonic acid, paratoluenesulfonic acid or methanesulfonic acid, an organic acid such as glyoxylic acid or Amberlyst™ catalyst, a solid, macroporous, lightly crosslinked sulfonated polystyrene divinylbenzene resin catalyst from Rohm and Haas. The mixture was heated, generally to 90 to 160°C, preferably 100 to 150 or to 120°C for a suitable time, such as 30 minutes to 6 hours, preferably 1 to 4 hours to remove condensation water. Time and temperature were correlated so that the reaction at a lower temperature will generally require a longer time, etc. Determining the exact conditions is within the skill of the person skilled in the art. If desired, the reaction mixture can then be heated to a higher temperature, e.g. 140-180°C, preferably 145-155°C, to further drive off volatile substances and drive the reaction to completion. The product may be treated with a base such as NaOH if desired to neutralize the strong acid catalyst and to produce a sodium salt of the product, if desired, and is then isolated by conventional techniques such as filtration or the like. The product of the reaction can generally be seen as comprising polymers or oligomers with the following repeating structure:

and positional isomers thereof.

Part of the formaldehyde which is preferably used, however, is believed to be incorporated into the molecular structure in the form of the substituent groups and crosslinking groups as illustrated by the following types, including ether linkages and hydroxymethyl groups:

Production of pour point reducers by the above method gives a material which generally shows improved handling properties such as increased flash point compared to pour point depressants produced by previously known methods.

Example 3

A 5 liter flask composed similarly to that in Example 1 was filled with 1850 g of C3<>+alkyl from Example 1. The material was heated with stirring to 100°C and 11.2 g of concentrated sulfuric acid was added over a 10 minute period period, immediately followed by a 9.6 g fill of paraformaldehyde (91%). Eleven additional charges of paraformaldehyde were added over the next 3 hours to give a total of 115 g, during which time condensate was collected in the trap. After 3 hours a drop of antifoam was added and the temperature was raised to 115°C over 0.5 hours, this temperature held for 2 hours, followed by heating to 150°C for 0.3 hours and maintaining this temperature for 2 ,0 hours. 631 g of a commercial paraffinic high boiling solvent was added, the temperature reduced to 131°C. To the mixture was added 18.4 g of 50% by weight aqueous sodium hydroxide over a 10 minute period. The mixture was heated to 150°C for 0.5 hours and an additional 992 g of paraffinic solvent was added, as well as 95 g of filter aid. After an additional 1 hour at the temperature, the mixture was filtered at 75°C using additional filter aid, and the filter aid was washed with an additional 292 g of paraffinic solvent. The product is the filtrate, which contains about 50% paraffinic high-boiling diluent.

Example 4 (Reference example)

A 760 liter glass-encased reaction vessel equipped with a stirrer, a column, a condenser, a distillate receiver and a nitrogen inlet (570 l/h) was filled with 155 kg of C24-28 alkylphenol and 31 kg of commercial aromatic solvent. The mixture was heated with stirring to 79-85°C, whereupon 890 g of concentrated sulfuric acid was added. The mixture was heated to 104-110°C and 12.2 kg of paraformaldehyde (91%) was added in 9 equal portions over 5-6 hours, while the aqueous distillate was removed as it was generated. The mixture was heated to 118-124°C over three hours and held at this temperature for a further 2 hours, then to 127°C with the simultaneous addition of 1.35 g of 50% aqueous sodium hydroxide. The mixture was heated to 149-154°C over two hours (with increased nitrogen yeast stirring) to remove residual water. The mixture was cooled to 60°C and 126 kg of additional commercial aromatic solvent was added to give 50% solvent. The mixture was filtered at 60-66°C using 2.7 kg of filter aid.

Example 5

The procedure of Example 4 was largely repeated using an equimolar amount of C30+ alkylphenol instead of C24-2s alkylphenol. For this example, no solvent was used in the initial step of the reaction, but the amount added after the reaction is the amount calculated to give 50% polymer, 50% solvent. In an alternative embodiment of this example, the solvent is used as in example 4.

Examples 6-13

The pour point depressant prepared as in Example 3 was added in 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 reducer was added in a conventional manner, i.e. by mixing into the crude oil at a temperature above the pour point of the oil, although other methods of addition will be obvious to the person skilled in the art. The floating points were reduced as indicated.

Figure 1 shows the composition of an Anadarko Tucker crude oil corresponding to that of Examples 8 and 11, represented by weight % as a function of boiling fraction. The large peak for C40 in both cases accounts for the sum of the components that come in the C40 range and above.

In some of the above formulations, the crystallization point as well as the pour point are reduced. The pour point reducing agents according to the present invention can be supplied in 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 may be added as dispersions in such materials as acetates (eg as 2-ethoxyethyl acetate) or as aqueous glycol mixtures (eg mixtures of ethylene glycol and water).

Claims (12)

1. Waxy liquid composition, characterized in that it comprises: c) a waxy liquid having an initial pour point of at least 4°C, and d) an amount sufficient to reduce the pour point of the waxy liquid by at least 0.6°C, where the amount is at least 50 ppm, of a pour point depressant comprising the reaction product; i) a hydrocarbyl substituted phenol with a number average of more than 30 carbon atoms in the hydrocarbyl substituent and ii) an aldehyde with 1 to 12 carbon atoms or a source thereof. 2. Composition according to claim 1, characterized in that the waxy liquid has an initial pour point of at least 16°C. 3. Composition according to claim 1, characterized in that the number average number of carbon atoms in the alkyl substituent is 31 - 40. 4. Composition according to claim 1, characterized in that the aldehyde is formaldehyde or a source thereof. 5. Composition according to claim 1, characterized in that the reaction product comprises the reaction of the hydrocarbylphenol and the aldehyde or the source thereof, in a molar ratio of 2:1 to 1:1.5 and where the reaction product comprises 2 to 100 aromatic units. 6. Composition according to claim 1, characterized in that the waxy liquid is an oil that has a wax content of more than 5%. 7. Composition according to claim 1, characterized in that the waxy liquid is an oil where the fraction boiling between 271°C and 538°C comprises at least 25% of the oil excluding any fraction with 7 or fewer carbon atoms. 8. Composition according to claim 1, characterized in that the waxy liquid is an oil having a weight average number of carbon atoms of more than 18, exclusive of any fraction with 7 or fewer carbon atoms. 9. Composition according to claim 1, characterized in that the pour point reducing agent amounts to 50 to 10,000 ppm based on the waxy liquid. 10. Process for reducing the pour point of a waxy liquid which has an initial pour point of at least 4°C, characterized in that it comprises adding to said liquid a pour point reducing amount of a pour point reducing agent comprising the reaction product of i) a hydrocarbyl substituted phenol with a number average of more than 30 carbon atoms in the hydrocarbyl substituent and ii) an aldehyde of 1 to 12 carbon atoms or a source thereof. 11. Method according to claim 10, characterized in that the pour point reducing agent is added to the waxy liquid with mixing at a temperature that is above the pour point of the waxy liquid. 12. Use of a pour point depressant comprising the reaction product of i) a hydrocarbyl substituted phenol having a number average of more than 30 carbon atoms in the hydrocarbyl substituent and ii) an aldehyde of 1 to 12 carbon atoms, or a source thereof, to reduce the pour point of a waxy liquid having an initial pour point of at least 4°C.