GB2039944A - Treatment of coal liquids and coal bottoms - Google Patents

Abstract

Coal liquids are rendered compatible with petroleum liquids and the solubility of heavy fractions of coal (e.g., coal liquefaction bottoms) is obtained by selective oxygen alkylation and/or oxygen acylation by use of a phase transfer reagent and an oxygen alkylating and/or acylating agent. The phase transfer reagent is a quaternary base represented by the formula R4QOR'' where each R is the same or different and is C1 to C20 alkyl or C6 to C20 aryl; Q is nitrogen or phosphorus, and R'' is C1 to C10 alkyl, C6 to C10 aryl, C7 to C10 alkaryl, C7 to C10 aralkyl or C1 to C10 acetyl. The O-alkylation or O- acylation agent is a compound represented by the formula R'X where R' is a C1 to C20 alkyl or acyl group and X is a halide, sulfate, bisulfate, acetate or stearate; provided X is attached to a primary or secondary carbon atom.

Description

SPECIFICATION Treatment of coal liquids and coal bottoms This invention is directed to improving the properties of heavy coal fractions and, in particular, to increasing the solubility of heavy coal fractions in common organic solvents and petroleum liquids.

Processes for the liquefaction of coal and similar carbonaceous solids usually involve contacting the feed material with a hydrocarbon solvent and molecular hydrogen at elevated temperature and pressure. This results in partial breakdown of the complex high molecular weight starting material into lower molecular weight hydrocarbon liquids and gases. These are recovered from the liquefaction effluent, leaving a heavy liquefaction bottoms product which normally boils in excess of about 1 000"F and generally contains suslended solid residues. The liquefaction bottoms may constitute 50% or more by weight of the total liquefaction products.

A major use of coal liquids, particularly high boiling coal liquids, could be in a fuel blend consisting of both coal and petroleum liquids. Unfortunately, coal liquids, such as those derived by hydrogenation processes, do not appear to be compatible with petroleum liquids in that addition of small amounts of the former to the latter causes precipitation.

Without subscribing to any particular theory, one likely reason for this is that coal liquids are more polar than petroleum liquids, due to the presence of phenolic and carboxylic funcionalities. These polar functionalities cause intermolecular asociation between adjacent coal liquid molecules and tend to hold the liquid molecules together by a network of hydrogen bonds. Petroleum liquids, which lack these polar functional groups, cannot participate in the intermoiecular association. As a result, segregation occurs, and the petroleum and coal liquids separate into distinct layers.

Avariety of different processes for upgrading liquefaction bottoms have been proposed in the past.

Exemplary of these include pyrolysis of the bottoms that produce gases, additional hydrocarbon liquids and coke, followed by steam gasification of the coke to form hydrogen and carbon monoxide for use as a fuel; see e.g., U.S. Patent 4,060,476. Another process for upgrading liquifaction bottoms is disclosed in U.S.

Patent 4,089,772 which discloses an acid-catalyzed C-alkylation or C-acylation of liquefaction product bottoms prior to recycling the bottoms fraction to the liquefaction reaction zone.

These various processes result in more efficacious use of liquefaction bottoms. However, during subsequent coal liquefaction process, phenols present in the coal are cleaved to produce water. In liquefaction processes employing hydrogen, an excessive use of hydrogen thus occurs.

Solvent extraction of coal also leaves behind a high molecular weight, insoluble fraction of coal called coal solubilization bottoms. Like liquefaction bottoms, this heavy fraction is also the object of various upgrading processes in order to obtain increased liquid yields.

In accordance with the present invention, functionalities having weakly acidic protons in coal liquids and heavy coal fractions or bottoms are treated by alkylation or acylation (sometimes referred to herein as oxygen or O-alkylation and oxygen or O-acylation). Weekly acidic protons include phenolic, carboxylic and mercaptan functionalities. The O-alkylation or O-acylation is conveniently carried out by use of a phase transfer reagent and an alkylating or acylating agent. The phase transfer reagent, which is recyclable, is a quaternary ammonium or phosphonium base (aR4QOR"), where each R is the same or different group and is a C1 to C20 alkyl or C6 to C20 aryl group: Q is nitrogen or phosphorus; and R" is hydrogen, C1 to C10 alkyl, C6 to C10 aryl, C71Co alkyl.C7 to C,O aralkyl or C, to C,O. The alkylating and acylating agents are represented by the formula R'X where R' is a C, to C20 alkyl or acyl group and X (a leaving group) is a halide, sulfate, bisulfate, acetate or stearate, provided Xis attached to a primary or secondary carbon atom.

O-alkylated or O-acylated coal liquids and heavy coal fractions show increased solubiliyy in common organic solvent and are more compatible with petroleum liquids than those not so treated.

The process disclosed herein may be advantageously employed with any coal liquid or bottom, regardless of derivation.

Coal liquids and heavy fractions (bottoms) are those materials derived from coal by a variety of processes including hydrogenation and donor solvent reactions involving a distillaton to remove coal liquids. Coal liquefaction bottoms, though only a by-product of the liquefaction process, constitute an undesirably large fraction of the total liquefaction products. Exemplary of the solvent hydrogen donor liquefaction process is that described in U.S. Patent 3,617,513.

Coal solubilization bottoms are those residues derived from coal by a variety of solvent extraction processes. Exemplary of the solvent extraction process is that described in U.S. Patent 3,607,716, which discloses supercritical gas extraction.

The alkylation or acylation process disclosed herein may be advantageously employed with any heavy coal fractions, regardless of derivation. As used herein, the terms "coal bottoms" and "heavy fractions" are synonymous and relate to coal residues derived by coal treatment processes such as liquefaction, solubilization and the like. Certain gasification processes yield a by-product tar, which is also a coal residue contemplated for treatment by the process of the invention.

By the process of the invention, functionalities containing weakly acidic protons in the treated material are chemically altered. For example, acidic proton-containing groups such as phenolic and carboxylic, which are very polar functional groups are converted to relatively non-polar ethers and esters, respectively. The chemical transformation may be represented as follows: Ar-OH + R'X , Ar-OR' Ar-COOH + R'X > Ar-COOR' where R' is a C1 to C20 alkyl or acyl group.

The O-alkylation or O-acylation of coal liquids or coal bottoms by reagents which are in liquid solution is greatly influenced by the use of a phase transfer reagent. Such a reagent has both a lipophilic and a hydrophilic portion and is capable of transferring a basic species, -OR", from an aqueous phase to either a solid or liquid organic phase, where R" is either hydrogen or a carbon-bearing functionality. The phase transfer reagent may be generated catalytically, in which case the process is termed a phase transfer catalysis, which is a well-known reaction; see, e.g., Vol. 99, Journal of the American Chemical Society. pp.

3903-3909, (1977). Alternatively, the reagent may be generated in a separate step, then used in the alkylation or acylation reaction. If this latter reaction is employed, then the active form of the reagent may be regenerated in a subsequent step. In either case, the overall chemical transformation on the coal bottoms is the same. A generalized mechanistic scheme for this transformation is shown below.

The phase transfer reagent is a quaternary base represented by the formula R4QOR" where R is is preferably C, to C6 alkyl or preferably C6to C12 aryl group; 0 is preferably nitrogen; and R" is preferably C1 to C6 alkyl or acetyl group; more preferably a C1 to C4 alkyl group and most preferably hydrogen. The phase transfer reagent may be generated by reacting the corresponding quaternary salt R4QX with a metal base MOR" where X is a halide, sulfate, bisulfate, acetate or stearage. Preferred is when X is a halide, especially chlorine, bromine or iodine, more preferably chlorine. M is an alkali metal or alkaline earth metal, more preferably sodium or potassium.As shown above, the quaternary base is then reacted with the acidic groups on the coal which in turn is reacted with at least one alkylating or acylating agent represented by the forumla R'X wherein R' is a C1 to C20 alkyl or acyl group and X is as previously defined, as long as Xis attached to a primary or secondary carbon atom. Preferably R' is an inert hydrocarbon, e.g. a C1 to C4 inert hydrocarbon, that is a hydrocarbon group containing only hydrogen and carbon, although hydrocarbon groups containing other functionality may also be suitable for use herein, even though less desirable. It will be noted that the acidic proton H (hydrogen atom) is usually located on phenolic groups in higher rank coals and on carboxylic groups for lower rank coals.The acidic proton may also be located to a lesser extent on sulfur, nitrogen, etc.

Phase transfer reagents such as quaternary ammonium base (R4QOR") are very effective in the O-alkylation and O-acylation of coal bottoms. These O-alkylation and O-acylation reactions are successful because the -OR' portion of the molecule is soluble in an organic medium. When this base is present in such a medium, it is not solvated by water or other very polar molecules. As an unsolvated entity, it can react as a very efficient proton transfer reagent. For example (Coal)-OH + OR" ~ (Coal)-O + R"OH In one embodiment of the process of the invention, a two-phase solid;liquid or liquid liquid system comprising the coal bottoms or coal liquids in liquid suspension is formed.If coal bottoms are heated they may be ground to a finely divided state and contain particles less than about 8 mesh NBS sieve size, more preferably less than about 8 mesh. The smaller particles, of course, have greater surface area and thus alkylation or acylation will proceed at a faster rate. Consequently, it is desirable to expose as much coal surface area as possible without losing coal bottoms as dust or fines or as the economics of coal grinding may dictate. Thus, particle sizes greater than about 325 mesh are preferred. Also, in the case of coal liquids, a three-phase system comprising the coal liquid and aqueous phase, together with a petroleum liquid, may be employed.

Although not necessary, a solvent may be added if desired. The solvent may be used to dissolve alkylated or acylated carbonaceous product or to dissolve alkylating or acylating agent (especially if the agent is a solid and is comparatively insoluble in water). The solvent may also be used to provide for more efficient mixing. Many of the common organic solvents may be employed in any reasonable amount, depending on the desired result.

The phase transfer reagent that is used must dissolve in or be suspended in both phases so that it has intimate contact with both the organic and aqueous phases. During the course of the reaction, the phase transfer reagent will partuition itself into both of these phases. Quaternary basis are useful as phase transfer reagents in the practice of the invention and have the formula R4QOR", as previously defined and exemplified. The lower number of carbon atoms for R is preferred, since such compounds are more water soluble and can be removed from the alkylated or acylated coal bottoms by simple water washing. The R groups may be the same or different. Examples of R groups include methyl, butyl, phenyl and hexadecyl.

Examples of quaternary bases useful in the practice of the invention include the following: 1. Tetrabutylammonium hydroxide (C4Hg)4NOH 2. Benzylhexadecyldimethylammonium hydroxide, (C6H5CH2)(C,6H33)(CH3)?NOH 3. Tetrabutyl phosphonium hydroxide (C4H9)4POH 4. ADOGEN 464, (C8-C10)4NOH (ADOGEN 464 is a trademark of Aldrich Chemical Co., Metuchen, NJ).

The metal base used to convert the quarternary salt to the corresponding base is an alkali metal or alkaline earth metal base such as NaOH, KOH, Ca(OH)2 or NaOCH3. The use of an alkoxide, for example, permits use of the corresponding alcohol in place of water, which may provide an advantage of treating coal bottoms under conditions where water is not desired.

In choosing the alkylating and acylating reagent, two considerations must be weighed. First, it is desired to add longer chains to the coal liquids or bottoms which render the product more petroleum-like, and therefore, more soluble in organic solvents and more compatible with petroleum liquids. On the other hand, shorter chains render the alkylated or acylated coal liquids or bottoms more volatile. Second, shorter chain materials are also less expensive and still improve solubility.

In the case of O-alkylation, the carbon to which the leaving group is attached may be either a primary or secondary carbon atom. Primary carbon halides have been found to react faster than the corresponding secondary halides in a phase transfer or phase transfer catalyzed reaction on carbonaceous materials and are accordingly preferred. While the balance of the carbon-bearing functional group may, in general, contain other moieties, such as heteroatoms, aryl groups and the like, bonding of the carbon-bearing functional group to the phenolic or carboxylic oxygen is through either an sp3 hybridized carbon atom (alkylation) or an sp2 hybridized carbon atom (acylation). Further, a mixture of alkylating or acylating agents or a mixture of both may advantageously be employed.Such mixtures are likely to be generated in coal-treating plants in other processing steps and thus provide a ready source of alkylating and/or acylating agents. Examples of alkylating and acylating agents useful in the practice of the invention include ethyl iodide, isopropyl chloride, dimethyl sulfate, benzyl bromide and acetyl chloride.

Although alkylating andior acylating agents may be employed in the practice of the invention, alkylating agents are preferred for the following reasons. First, alkylating agents are readily prepared from their hydrocarbon precursors. For example, alkyl halides may be easily prepared by free radical halogenation of alkanes, which is a well-known process. When a system containing more than one alkylating or acylating agent is used, the hydrocarbon precursor is preferably a product stream of a certain cut derived from coal and petroleum processing and the like.This stream may contain minor amounts of components having various degrees of unsaturation which are also suitable for reacting with the phenolic and carboxylic groups herein, as long as X (as previously defined) is attached to an alkyl or saturated carbon atom in the resulting alkylating or acylating reagent. Second, acylating reagents are susceptible to hydrolysis. Since water is present due to the nature of the invention process, some loss of acylating agent may occur by hydrolysis. In contrast, alkylating reagents do not show the same susceptibility to hydrolysis.

If the O-alkylation or O-acylation is carried out by a catalytic process, then the quaternary salt, metal base and alkylating or acylating agent are mixed directly with the coal liquid or an aqueous slurry of coal bottoms.

The quaternary salt catalyst may be present in small amounts, typically about 0.05 to 10 wt. % of the amount of coal bottoms used; however, greater amounts may also be employed. If it is desired to O-alkylate or O-acylate all acidic sites on the carbonaceous material then the metal base and the alkylating or acylating agent must be present in at least stoichiometric quantities relative to the number of acidic sites (phenolic, carboxylic, etc.) on the coal liquid or bottoms, but preferably an excess of each is used to drive the reaction to completion. Advantageously, a two-fold excess of metal base and alkylating or acylating agent is employed; however, a greater excess may be employed. After the reaction, the excess quaternary base and quaternary salt catalyst may be removed from the coal liquid or bottoms by ample water washing for recycling.Excess metal base will also be extracted into the water wash, and it may be reused. Excess alkylating or acylating agent may be conveniently removed from the treated coal material by fractional distillation or by solvent extraction with pentane or other suitable solvent and may be reused. Of course, if it is desired to treat less than all the acidic sites on the carbonaceous material, less than a stoichiometric quantity of metal base and alkylating or acylating agent is employed.

To cap off all acidic protons in typical coal liquid or bottoms employed in the catalytic process, less than about 2 days are required for 100% conversion, employing only a slight excess of alkylating or acylating agent on -80 mesh coal bottoms or on coal liquids under atmosphere pressure and ambient temperature. A greater excess of alkylating or acylating agent will reduce the reaction time considerably.

Afasteralkylation or acylation reaction may be obtained in a number of ways, one of which is to add the phase transfer reagent (R4OOR") directly to the coal liquid or bottoms rather than to form this reagent in situ with the reaction in which coal fractions are alkylated or acylated. When this is done, substantially complete conversion of all the phenolic and carboxylic groups is achieved in a matter of minutes. The amount of quaternary base added ranges from about stoichiometric proportions to about 10 times the total number of acidic sites on the coal liquid andlor bottoms which are capable of undergoing alkylation or acylation. As before, the quaternary salt that is generated in the alkylation or acylation step may be recovered and recycled by reacting it with fresh metal base to regenerate the quaternary base.By employing this two-step process, there is no contact between metal base and the coal bottoms, and the reaction is essentially complete in about one hour.

In another embodiment, a blend of coal liquids and petroleum liquids and the alkylating or acylating agent is contacted with an aqueous solution containing the phase transfer reagent. The alkylation or acylation may be performed catalytically or non-catalytically, employing the procedures outlined above.

The temperature at which the reaction is carried out may range from ambient to the boiling point of the materials used. Increased temperature will, of course, speed up the reaction rate.

The reaction mixture may be stirred or agitated or mixed in some fashion to increase the interface or surface area between the phases, since there can be aqueous, organic liquid and/or solid coal bottoms phases present.

The reaction may be carried out at ambient pressure, although low to moderate pressures (about 2 to 20 atmospheres) may be employed along with heating to increase the reaction rate.

Once the reagents and solvent if they are removed from the alkylated or acylated'coal liquid or bottoms, infra-red analysis may be conveniently used to determine that all the hydroxyl groups having been alkylated or acylated. If the added alkyl or acyl group is IR-active, then the appearance of the appropriate infrared frequency is observed. Other well-known analytical methods may also be employed if desired. The ultimate analysis of percent C, H, N, S and 0 is altered in a fashion which is consistent with the expected change due to the added alkyl or aryl substituent. For example, the increase in the H/C ratio of O-methylated coal bottoms from Illinois No. 6 coal indicates that 3.5 methyl groups per 100 carbon atoms are added to the coal bottoms.The H C ratio in the untreated coal bottoms of Illinois No. 6 coal is 0.754 and the H/C ratio after methylation by the process of the invention is 0.790. The thermogravimetric analysis of the methylated coal bottoms shows a significant increase in volatile organic content over the untreated coal bottoms (48% versus 38%).

If coal liquids are treated the increase in the H/C ratio of O-methylated coal liquid derived from Illinois No. 6 coal indicates that 3.5 methyl groups per 100 carbon atoms are added to the coal liquid. The H/C ration in the untreated coal liquid derived from Illinois No.6 coal is 1.004 and HiC ratio after O-methylation by the process of the invention is 1.037. The treated coal liquids become more soluble in common organic solvents. For example, the solubility (20-C) of O-methylated coal liquids in cyclohexane increases to 63% from 11% for untreated coal liquids.

The alkylated and acylated coal liquids formed by the process of the invention and are compatible with petroleum liquids, as indicated by the increased solubility of alkylated and acylated coal liquids in petroleum liquids. Blends of coal liquids treated in accordance with the invention and petroleum liquids evidence increased stability.

Coal bottoms treated in accordance with the invention may be recycled through the liquefaction, gasification, solubilization, etc., processes from which they were derived. Liquid products derived are more compatible with petroleum liquids than those derived from coal bottoms not so treated. The solvent extractability of the coal bottoms is greatly increased after it is P-alkylated or O-acylated. For example, Illinois No. 6 coal bottoms become more soluble in common organic solvents after oxygen-methylation, as shown in Table I below.

TABLE I Maximum Solubility (at 1 atoms {DMMF) Toluene Tetrahydrofuran Illinois No. 6 Coal Bottoms 22 60 O-methylated Illinois No. 6 coal bottoms 95 95 Coal liquids which are derived by solvent extraction of coal bottoms treated in accordance with the invention evidence both improved quality and increased quantity over coal liquids derived from untreated coal.

EXAMPLES Example 1 - Phase Transfer CatalyzedAlkylation A coal liquid derived from Illinois No. 6 coal by Exxon's donor solvent process was treated as follows: In a 250 ml round bottom flask which was flushed with nitrogen and equipped with a mechanical stirrer were added the following components: 5.0 g of coal liquids (650-1050"F, derived from Illinois No, 6 by hydrogen donor solvent liquefaction), 0.25 g of tetrabutylammonium iodide (as received from Aldrich Chemical), 50 ml of toluene (spectrograde from Matheson, Coleman and Bell, purged with nitrogen 1 35 ml of 20% aqueous solution of NaOH (purged with nitrogen) and 11.0 g of iodomethane (added dropwise with vigrous stirring). A nitrogen atmosphere was maintained for 5 days, until the reaction was assumed to be complete.The layers were separated in a separatory funnel. The organic layer was washed eleven times with 150 cc portions of water to remove caustic and catalyst. The toluene and residual iodomethane were stripped off under vacuum at 100 C.

The solubility (20 C) of coal liquid vacuum gas oil increased from 11% to 63% in cyclohexane after phase transfer catalyzed O-methylation in cyclohexane solvent.

A one to two order of magnitude increase in solubility of the O-methylated (versus untreated) coal liquid vacuum gas oil in a petroleum liquid, which was a desulfurized Aruba high viscosity fuel oil, was observed.

Examples 2-5 - Phase Transfer CatalyzedAlkylation The following reactions were carried out on various coal liquids employing the reagents in the amounts indicated shown in the following Table.

TABLE Phase Transfer Catalyzed Reactions Example Coal Liquid Solvent Catalyst(1) Caustic(2) R'X(3) 2 Vacuumgasoil Xylenes B, 10% NaOH,12% C4H9Cl,443% 3 Vacuum gas oil Toluene B, 3.3% NaOH, 12% C2H5l, 570% 4 Vacuum gas oil Toluene T, 5% NaOH, 20% CH3l, 1100% 5 Vacuum gas oil Toluene T,5% NaOH, 12% CH3l,200% Definition of Symbols (1) B is benzylhexadecyldimethylammonium chloride and T is tetrabutylammonium chloride; wt. percent is relative to coal liquid (2) Weight percent of metal base in water.

(3) Weight percent relative to coal liquid.

Examples 6-14-Phase Transfer Catalyzed Alkylation Coal liquefaction bottoms derived from Illinois No. 6 and Wyodak coals are treated employing the reagents and amounts set forth in Table II below. In each case, the reactants were mixed together for 1 to 2 days at ambient temperature.

TABLE II Phase Transfer Catalyzed Reactions Example Coal Liquefaction Bottoms (1) Solvent Catalyst(2) Caustic(3) R'X (4) 6 CLPP Bottoms-III. No 6 (-80) Benzene B, 20% NaOH, 50% C2H5l, 2920% 7 CLPP Bottoms-III. No 6 (-80) Toluene B, 10% NaOH, 50% CH3l, 3900% 8 CLPP Bottoms-III No 6 (-80) Toluene B 10% NaOH, 50% Propargylbromide, 158% 9 CLPP Bottoms-III. No 6 (-80) Toluene B, 10% NaOH, 50% Alylbromide, 526% 10 CLPP Bottoms-III No 6 (-80) Toluene B, 10% NaOH, 50% C7H15l, 460% 11 CLPP Bottoms-III. No 6 (-80) Toluene B, 10% NaOH, 40% CD3l, 760% 12 CLPP Bottoms-III, No 6 (-80) Toluene B,5% NaOH, 50% (CH3)2SO4, 1200% 13 CLPP Bottoms-III. No 6 (-80) Toluene B, 10% NaOH, 50% C10H21Br, 380% 14 CLPP Bottoms-III. No 6 (-80) Toluene B, 10% NaOH, 40% C2H5l, 731% 15 CLPP Bottoms-III. No 6 (-80) Toluene T,5% NaOH, 12% CD3l, 100% 16 CLPP Bottoms-III.No 6 (-80) Toluene T,5% NaOH, 12% CH3l, 250% 17 U.S. Steel Full Range Tar Xylenes A,4% NaOH, 20% CH3l, 314% 18 CLPP Bottoms-Wyodak Toluene T,5% NaOH, 12% CH3l, 230% 19 CLPP Bottoms-Wyodak T 5% NaOH, 12% C4H9l, 258% Definition of Symbols (1) Coal origin of bottoms is given: CLPP - Coal Liquefraction Pilot Plant; Mesh size is indicated in parantheses.

(2) B is benzylhexadecyldimethylammonium chloride, A is ADOGEN 464 and T is tetrabutylammonium iodide. Weight percent is relative to carbonat material.

(3) Weight percent of metal base in water.

(4) Weight percent relative to coal bottoms.

In the case of CLPP bottoms, 3.5 alkyl groups were added to each 100 carbons in the sample. The H/C ratio of each sample increased in accordance to the chain length of the alkyl group added. The O-alkylated bottoms evidenced greater volatility and solubility in a variety of solvents and were more hydrogen rich and less viscous than the untreated bottoms.

A comparison between untreated coal liquefaction bottoms and O-methylated coal liquefaction bottoms gave the results shown in Table Ill below.

TABLE Ill Comparison between untreated and treated coal bottoms Coal Liquefaction O-Methylated Coal Property Bottoms Liquefaction Bottoms Softening point ("C) 210 120 Apparent viscosity (poise at 232"C) 185 19.5 Apparent viscosity (poise at 316"C) 25 1 % Volatile matter 38 48 % Oxidized 62 52 T1(0C) 310 250 Tf(0C) 600+ 580 Table Ill shows a dramatic decrease in the softening point and viscosity of coal bottoms, which improve processability. Phase transfer alkylation increases the volatile organic portion of liquefaction bottoms and lowers the boiling range (Ti and Tf). Thus, more usable volatile organic coal bottoms are recovered by distillation.

Claims (12)

1. A method for improving the properties of coal liquids of coal bottoms by oxygen-alkylation and/or oxygen-acylation, which comprises contacting the coal liquids or coal bottoms with a solution comprising; (a) at least one quaternary base represented by the formula R4QOR" where each R is the same or different and is C, to C2O alkyl or C6to C0 aryl;Q is nitrogen or phosphorus; and R" is C, to C,O alkyl, C6to C10 aryl, C7 to C10 alkaryl, C7 to C,0 aralkyl or C1 to C,0 acetyl; and (b) at least one compound represented by the formula R'X where R' is a C1 to C0 alkyl or acyl group and Xis a halide, sulfate bisulfate, acetate or stearate; provided Xis attached to a primary or secondary carbon atom.

2. A method according to claim 1 wherein B" is a C, to C4 alkyl group or hydroge, R is a C, to C6 alkyl group, R' is a C, to C4 inert hydrocarbon and Xis chlorine, bromine or iodine.

3. A method according to claim 2 wherein Xis chlorine, R' is a methyl group and 0 is nitrogen.

4. A method according to any one of the preceding claims wherein the amount of quaternary base ranges from stoichiometric to 10 times the total number of acidic sites of the coal liquid or coal bottoms.

5. A method according to any one of the preceding claims wherein R'X is present in at least a stoichiometric amount relative to the number of acidic sites of the coal liquid or coal bottoms.

6. A modification of the method according to any one of the preceding claims wherein a quaternary salt represented by the formula R4QX is reacted with an alkali metal or alkaline earth metal base represented by the formula MOR" to form the corresponding quaternary base, wherein M is an alkali metal or alkaline earth metal.

7. A method according to any one of the preceding claims wherein the reaction is carried out catalytically.

8. A method according to claim 7 wherein the amount of quaternary salt is a catalytic amount ranging from 0.05 to 10 wt. % of the coal.

9. A method according to claim 6 wherein the quaternary base is formed separate from the alkylation or acylation reaction.

10. A method accirding to claim 6 which is repeated at least once.

11. A method for improving the properties of coal liquids or coal bottoms according to claim 1 substantially as herein described with reference to the Examples.

12. Coal liquids or coal bottoms whenever produced by a method according to any one of the preceding claims.