CA1140064A - Treatment of solid, naturally-occurring carbonaceous material by oxygen-alkylation and/or oxygen acylation - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
Treatment of weakly acidic protons in solid, naturally-occurring carbonaceous material, such as coal, by selective oxygen-alkylation and/or oxygen-acylation by employing a phase transfer reagent and an oxygen-alkylating and/or acylating agent.

Description

1 BACKGROUND OF ~XE INVENTION

2 1. Field of the Invention

3 Thi9 invention is directed to i~proving properties of

4 solid, naturally-occurring carbonaceous material such as coal and, in par~icular, to improving y~elds and physical 6 characteristics of coal liquefaction distillates and 7 bottoms.
8 2. Description of the Prior Art g Much work has been done in recent years to make useful llquids and gases from coal. Various types ~f liquefaction 11 processes have been developed, such as solvent refining, 12 direct hydrogenation with or without a catalyst, catalytic 13 or non-catalytic hydrogenation in the presence o~ a non-14 donor ~olvent, and catalytic or non-catalytic liquefaction by the donor solvent method. Exemplary of the solvent 16 hydrogen donor liquefaction process is U~S. Patent 3,617,513.
17 In an effort to increase liquefaction yields, a number 18 of ancillary processes have been developed, such as pretreat-19 ment of coal prior to the liqueaction process or post-treat-ment of products derived from the liquefaction process, e.g., 21 liquefaction distillates, coal liquids and bottoms. Exemplary 22 of pretreatment processes is U.S. Patent 4,092,235, which 23 discloses acid-catalyzed Friedel-Crafts C-alkylation or 24 C-acylation of coal ~o increase the yield of products from coal liquefaction. The introduction of aliphatic hydro-26 carbon radicals or acyl radicals, including carbon monoxide, 27 i~to the coal structure is believed to permit a greater 28 quantity of the coal to undergo liqu~faction at suitable 29 liquefaction conditions. The alkylation or acylation reactions, which may be conducted ~n the presence or absence 31 of added or extraneous catalysts, take place at carbon si~es.
32 Many of the C-alkylation and C-acylation processes 33 require a considerabLe amount of alkylating or acylating 3~ agent in order to accompl sh their purpose. Further, during the subsequent coal liquefaction process, phenols present in 36 the coal are cleaved to produce water. In liquefaction 1 processes employing hydrogen, an excessive use of hydrogen 2 thus occurs.
3 SUMMARY OF T~ INVENTION
4 In accordance with the invention, properties of solid, naturall~-occurring carbonaceous materials, such as coal, 6 are improved. Also, coal lique~ac~.ion distillates and 7 bottoms having improved p-operties are formed by a process 8 which comprises (a) treating functionalities having weakly 9 acidic protons in coal by a process selected from the group consisting of alkylation and acyla~ion, and (b) subjecting ll the treated coal to liquefaction process. Weakly acidic 12 protons include phenolic, carboxylic and mercaptan func-13 tionalities. The O-alkylation or O~acylation is conven-14 iently carTied out by use of a phase trans~er reagent and an alkylating or acylating agen~. The phase transfer 16 reagent, wnich is recyclable, is, by way o~ example, a 17 quanternary ammonium ~ phosphonium base (R4QOR"), where R
18 is the same or different group seLected from the group l9 consisting of Cl to about C~0 ~ll.cyl and r6 to abvu~ ~2~ aryL
Q is nitrogen or phosphorus; and R" is selected from the 21 group consisting of hydrogen, Cl to about C~ yl, a~yl 22 a~lylaryl, arylalkyl and ac~e~ 1. The alkyLating and 23 acylati~g agents ar~ ~ cnt~ by the formula R'X where 24 R is a Cl 20 or acyl group and X is a leaving group selected fr~m the group Gonsisting of halide, sulfa~e, 26 bIsulfate acetate and stearate, wherein X is a~tached to 27 a primary or secondary carbon atom.
28 The O-alkylated or O-acylated coal is then sub~ected to 29 a coal liquefac~ion process to produce distillable coal liquids. These coal liquids are formed in greater yields and 31 have more desirable properties than those formed from ~he 32 same liquefaction process but using untreated coal. The im-33 proved physical properties of these coal liquids are reduced 3~ viscosity, lower boiling ranges and increased compatlbility with petroleum liquids. The excessive use of hydrogen to 36 produce water is also avoided in the liquefaction of ~ ~ ~O Q ~ ~ ~

1 O-alkylated and O-acylated coals employing hydrogen-based 2 liquefaction schemes.

4 The Figure schematically illustrates one process for effecting and utilizing the preferred embodiment of this 6 inventiOn.
7 DETAILED DESCRIPTION OF THE INVENTI()N
.
8 The procedure that follows is especially useful for the g selective o-alkylation or O-acylation of bituminous, sub-bituminous and lignite coals usually employed in liquefaction 11 processes or other solid, naturally-occurring carbonaceous 12 materials employed in various ca~^bonaceous conversion 13 processes. The ~henolic and carboxylic functlonal sub-14 stituents in the coal are chemically altered. These two very polar functional groups are converted to relatively 16 non-polar ethers and esters, respectively. The chemical 17 transformation may be represented as follows:
18 Ar-OH ~ R'X~ Ar-OR' 19 AR-COOH ~ R'X Ar-COOR' where R' is a Cl to about C~0 alkyl or acyl group,and ~;is 21 an aromatic substituent.
22 The O-alkylation or O-acylation of solid coal by reagents 23 which are in liquid s~lution is greatly influenced by use of 24 a phase transfer reagent. Such a reagent has both lipophilic and a hydrophilic portion and is capable of transferring a 26 basic species, -OR", from an aqueous phase to either 27 a solid or liquid organic phase, where R" iS ei~her 28 hydrogen or a carbon-bearing functionality. The phase 29 transfer reagent may be generated catalytically, in which case the process is termed a phase transfer catalysis, which 31 is a well-known reaction; see, e.g. Vol. 99, ~ournal of the 32 American Chemical ~ociety, pp. 3903-3909 (1977). Al~er-33 natively, the reagent may be generated in a separate step, 34 then used in the alkylation or acylation reaction. If this latter reaction is employed, then the active form of th~
36 reagent may be regenerated in a subsequent step. In either Qfi~

1 case, the overall chemical transformation on the solid 2 coal is the same. A generalized mechanistic scheme of 3 this transformation is shown below:
4 _ R4QX + M:OR'' ~ 4 R4QOR'' ~ M X
Coal-H ~ R4QOR" _ ~Coal-QR4 + ~''OH
6 Q 4 ~ Coal-R' + R4QX
7 The phase transfer reagent is preferably a quaternary 8 base represented by the formula R4QOR" where each R is the 9 same or different group selected from the group consisting of Cl to about C20, preferably Cl to C6 alkyl and C6 to 11 about C20, preerably C6 to C12 aryl group; Q is nitrogen 12 or phosphorus, preferably nitrogen, and R" is selected from 13 the group consisting of hydrogen, Cl to about C10, pref-14 erably Cl to C6 a~kyl, aryl, a~kylaryl, arylalkyl and acetyl group more preferably a Cl to C4 alkyl group and 16 most preferably hydrogen. The phase transfer reagent 17 may be generated by reacting the corresponding quaternary 18 salt R4QX with a metal base ~O~" where X is selected from 19 the group consisting of halide, sulfate, bisulfate, acetate and stearate. Preferred is when X is a halide 21 selected from the group consisting of chlorine, bromine 22 and iodine, more preferably chlorine. M is selected from 23 the group consisting of alkali metals, more preferably 24 sodium and potassium. As shown above, the quaternary base is then reacted with the acidic groups on the coal 26 which in turn is reacted with at least one alkylating or 27 acylating agent represented by the formula R'X wherein 28 R' is selected from the group consisting of Cl to about 2~ C20 alkyl or acyl group and X is as previously defined, as long as X is attached to a primary or secondary carbon 31 atom. Preferably R' is an inert hydrocarbon, that is, a 32 hy~rocarbon group containing only hydrogen and carbon 33 although hydrocarbon groups containing other functionality 34 may also be suitable for use herein, even though less desirable. It will be noted that the acidic proton H
36 (hydrogen atom) is usually loca-ted on phenolic groups for 37 lower rank coals. The acidic proton may also be located 38 to a lesser extent on sulfur, nitrogen, etc.

~14~fi4 1 Phase transfer reagents such as quaternary ammonium 2 base (R4QOR") are very effective with O-alkylation 3 and O-acylation of coal. These O-alkyla~ion and 4 O-acylation reactions are successful because the -o~"
portion of the molecule is soluble in an organic medium.
6 When this base is present in such a medium, it is not 7 solvated by water or other very polar molecules. As an 8 unsolvated entity, it can react as a very efficient proton 9 transfer reagent. For example, lQ (coal) - OH + OR"~ b ~coal) - O + R"OH
11 This unsolvated base (also known as a "naked hydroxide"
12 when R'l is hydrogen) can have a wide variety of counter 13 ions. Although the counter ion may be quaternary ammonium 14 or phosphonium species as previously discussed, other examples o counter ions useful in the practice of the 16 inventlon include "crown ether" complexes of a salt 17 containing the OR" anion and clathrate compounds, complexed 18 with a salt containlng the OR" anion. Salts represented by 1~ MOR", wbere M is as given above, when complexed with crown 2~ Qthers,fr examPle,have been previously demonstrated to 21 evidence a reactivity similar to that found for R4QOR"
~2 compounds.
3 In one embodiment of the process of the invention, a two-~4 phase solid/liquid system comprising the particular coal in ~5 liquid suspension is formed. The coal is generally ground 26 to a finely divided state and contains particles less than 27 about ~ inch in size, preferably less than about 8 mesh ~8 NBS sieve size, more preferably less than about 80 mesh. The 29 smaller particles~ of course, have greater surface area and 3Q thus alkylation or acylatlon will proceed at a faster rate.
31 Cons~quently, it is desirable to expose as much coal surface 32 area as possible without losing coal as dust or fines or as 33 the economics of coal grinding may dictate. Thus, particle 34 sizes of greater than about 325 mesh are pre~erred.
Although not necessary, a solvent may be added i~ desired.
36 The solvent may be used to dissolve alkylated or acylated 37 carbonaceous product or to dissolve alkylating or acylating 1 agent (especially if the agent is a solid and is compar-2 atively isoluble in water). ~he solvent may also be used 3 for more efficient mixing. Many of the common organic 4 solvents may be employed in any reasonable amount, depending on the desired result.
6 Inasmuch as there are solid coal particles which never 7 dissolve during the course of the reaction, there may be 8 some concern as to the extent of the reaction on these 9 particles. To verify the complete extent of the reaction, thase particles were collected and worked up separately on 11 numerous runs with a wide variety of alkylating agents as 12 well as coals. Infrared spectral analysis of th~s insoluble 13 portion of the coal reaction mixture showed that in every 14 case, substantially complete alkylatlon of the hydroxyl group had occurred. This is evidence that the phase transfer reagent 16 must have penetrated the solid coal structure and that the 17 resulting organic salt of the coal must have reacted with 18 the alkylating agent to produce the observed product. Thus, 19 the etherificatlon and esterification reactions are not merely taking place on the surace of the coal but through-21 ou~ the coal structure as well.
22 The phase transfer reagent that is used must dissolve 23 in or be suspended in both phases so that it is in intimate 24 contact with both the organic and aqueous phases. During the course of the reaction, the phase transer reagent will 26 partition itself lnto both of these phases. Quaternary 27 bases are one class of compounds useful as phase transer 28 reagents in the practice o the invention and are given by 29 the formula R4QOR", where R is an alkyl group having at leas' one carbon atom, and preferably 1 to 2~ carbon a~oms, 31 and more preferably 1 to 6 carbon atoms or an aryl group 32 having 6 to 20 carbon atoms, perferably 6 to 12 carbon 33 atoms. The lower number of carbon atoms is preferred, since 34 such compounds are water soluble and can be removed from the alkylated or acylated coal by simple water washing. The 36 R groups may be the same or diferent. Examples of B groups 11 4~ 4 ,, - 1 include methyl, butyl, phenyl and hexadecyl.
2 Examples of quaternary bases useful in the practice 3 of the invention include the following:
4 1. Tetrabutylammonium hydroxide (C4H9)4NOH
2. Benæulhexadecyldimethylammonium hydroxide (C6H5CH2) (Cl6H33) (cH3)2NoH
7 3. Tetrabutylphosphonium hydroxide, (C4Hg)4POH
3 4. ADOGEN 464, (C8-C10)4NOH (ADOGEN 464 is a g trademark of Aldrich Chemical Company, Metuchen, NJ).
11 The metal basa used to convert the quaternary salt to 12 the corresponding base is an alkali metal or alkaline earth 13 metal base such as NaOH, KOH, Ca(OH)2 or NaOCH3. The use of 14 an alkoxide, for example, permits use of the corresponding alcohol in place of water, which may provide an advantage in 16 process flexibility.
17 In chosing the alkylating and acylating reagent, two 18 considerations must be weighed. First, i~ is desired to 19 add longer chains to the coal which render the product more petroleum-likP, and therefore more soluble in organic 21 solvents and more compatible with petroleum liquids. On the 22 other hand, shorter chains render the alkylated or acylated 23 coal product more volatile. Second, shor~er chain materials 24 are less expensive and still improve solubility.
In the case of O-alkylation, the carbon to which the 26 leaving group is attached may be either a primary or 27 secondary carbon atom. Primary carbon halides have been 28 found to react faster than the corresponding secondary 29 halides in a phase transfer o phase transfer catalyzed reaction on carbonaceous materials and are accordingly 31 preferred. While the balance of the carbon-bearing 32 functional group may in general contain other moieties, 33 such as heteroatoms, aryl groups and the like, bonding of 34 the carbon-bearing functional group to ~he p~enolic or carbonoxylic oxygen is ~hrough either an sp3 hybridized 36 carbon atom (alkylation) of an sp hybridized carbon atom ' ~ ,-.

l (acylation)- Further, a mixture of alkylating or acylating 2 agents or a mixture of both may be advantageously employed.
3 Such mixtures are likely to be generated in coal-treating 4 plants in other processing steps and thus provide a ready source of alkylating and/or acylating agents. Examples of 6 alkylating and acylating agents useful in ~he practice of 7 the invention include ethyl iodide, isopropyl chloride, 8 dimethyl sulfate, benzyl bromide and acetyl chloride.
g While alkylating andtor acylating agents are employed in the practice of the invention, alkylating agents are ll preferred ~or the following reasons. First, alkylating 12 agents are readily prepared from their hydrocarbon pre-13 cursors. For example, alkyl halides may be easily pre-14 pared by free radical halogenation of alkanes, which is a well~known process. When a system con~aining more than 16 one alkylating or acy}a~ing agent is used, the hydrocarbon 17 precursor is preferably a product stream of a certain cut 18 derived from coal and petroleum processing and the like.
19 This stream may contain minor amounts of components having various degrees of unsaturation which are also suitable for 21 reacting with the phenolic and carboxylic groups herein as 22 long as X (as previously defined) is attached to an alkyl 23 or saturated carbon atom in the resulting alkylating or 24 acylating agentO Second, acylating reagents are susceptible to hydrolysis- Since water is ever present in coal and other 26 solid carbonaceous material and is employed in the inventive 27 process, some loss of acylating agent may occur by hydro-28 lysis. In contrast, alkylating reagents do not evidence the 29 same susceptibility to hydrolysis.
If the 0-alkylation e~ O-acylation is carried out by a 31 catalytic process, then the quaternary sal~, metal base and 32 alkylating or acylating agent are mixed directly with an 33 aqueous slurry of coal. The quaternary salt catalyst may be 34 present in small amounts, typically about 0.05 to 10 w~.% of the amount of coal used; howe~er, greater amounts may also 36 be employed. The metal base and alkylating or acylating : , ~ , . .

4~
g 1 agent must be present in at least stoichiometric quantities 2 relative to the number of acidic sites (phenolic, carboxylic, 3 etc.~ on the carbonaceous material, but preferably an 4 excess of each is used to drive the reaction to completion.
Advantageously, a two-fold excess of metal base and 6 alkylating or acylating agent is employed; however, a 7 greater excess may be employed. After the reaction, the 8 excess quaternary base and quaternary salt ca~alyst may be g removed from the coal by ample water washing ~or recycling.
Excess metal base will also be extracted into the water 11 wash and may be reused. Excess alkylating or acylating 12 agent may be conveniently xemoved from the trea~ed coal 13 by fractional distillation or by solvent extraction with 14 pentane or o~her suitable solvent and may be reused.
To cap of~ all acidic pro~ons in a typical coal 16 employed in the cataly~ic process, less ~han 5 days are 17 required for 100% conversion, employing onl~ a sli~ht excess 18 of alkylating or acyla~ing agent on 80/100 mesh coal under 19 atm~spheric pressure and ambient ~emperature. A greater excess of alkylating or acylating agent will reduce the 21 reaction time considerably.
22 A faster alkylation or acylation reaction may be 23 obtained in a number of ways, one of which is to add the 24 phase transfer reagent (R4QOR") directly to the carbon-aceous material rather than to form this reagent ln situ 26 with the reaction in which the carbonaceous material is 27 alkylated or acylated. When this is done, substantially 28 complete conversion of all the phenolic and carboxylic 29 groups are achieved in a matter of minutes. The amount of quaternary base added ranges from about stoichiometric 31 proportions to about 10 times the total number of acidic 32 sites on the carbonaceous material which are capable o~
33 undergoing alkylation or acylation. As be~ore, the 34 quaternary salt that is generated in the alkylation or acylation step may be recovered and recycled by reacting 36 it with fresh metal base to regenerate the quaternary 37 base. By employing this two-step process, there is no 3~ contact between metal base and the carbonaceous material, !

1 and the reaction is essentially complete in about one hour. ~
- 2 As an example, in 10g of Illinois No. 6 coal, there are 3 35 moles of Ax-OH groups. An excess of a quaternary 4 hydroxide along with an excess of an alkylating agent (about 4 to 5 times each) results in essentially complete alkylatio 6 in less than one hour at ambIent conditions. In contrast, 7 in the phase transfer catalyzed reaction, there is metal 8 ~ase present so that the alkylation ~or acylation) must 9 ~e carried out in an inert atmosphere, such as nitrogen, to avoid oxidation of the coal. In the case of the non-11 catalyzed process in which the formation of the transfer 12 reagent is kept separate from the alkylating or acylating 13 reaction, the rate of oxidation of the coal i5 slow enough 14 and is not competitive wIth the alkylation or acylation reaction~ Thereore, another advantage of this noncatalyzed 16 process is that the use of an inert atmosphere such as 17 nitrogen is not required.
18 The temperature at which the reaction is carried out may range from ambient to the boiling point of the materials -20 used. Increased temperature will,of course, speed up the 21 reaction rate.
22 The reaction mixture may be stirred or agitated or mixed 23 in some fashion to increase the interface or surface area 24 between the phases, since there can be aqueous, organic liquid and solid carbonaceous material phases present.
26 The reaction is carried out at ambient press~re, although 27 low to moderate pressures (about 2 to 20 atmospheres~ may be 28 employed along with hea~ing to increase the reaction rate.
29 Once the reagents and solvents, i~ any, are removed from the alkylated or acylated carbonaceous material, infrared 31 ~nalysis may be conveniently used to demonstrate that all 32 the hydroxyl groups have been allcylated or acylated. If 33 the added alkyl or acyl group is IR-active, then the 34 appearance of the appropriate infrared frequency is observed.
other well-known analytical methods may also be employed 36 if desired. The ultimate analysis of percent C, H, N, S and O
37 is altered in a fashion which is consistent with the expected .

Q~j~

1 change due to the added alkyl or acyl substituent. For 2 example, the inc~ease in the H/C ratio of 0-methylated 3 Illinois No . 6 coal indicates that 4.5 methyl groups per 4 100 carbon atoms are added to the coal. The H/C ratio of

5 the untreated Illinois ~oO 6 coal is 0.84 and the H/C ratio ~ after 0-methylation by the process of the invention is 0.890 7 The thermogravimetric analysis of the 0-methylated coal ~3 shows a significant increase in volatile organic content 9 over the untreated coal (38% versus 32%)o The solvent ex-1~ tractability of the carbonaceous material is greatly in-11 creased af~er it is 0-alkylated or O~acylated. For example, 12 Illinois No. 6 coal becomes more soluble in common organic 13 solvents after it is oxygen-me~hylated, as shown in Table I
14 below:
T~BLE I
~6 MAXIMU~I S~LUBILITY (at l atm) 17 Toluene TetrahYdrouranPYridine 18 Illinois #6 19 Coal 3% 17% 27%
20 0-methylated 21 Illinois #6 Coal 7% 22% 34%
22 Liquids which are derived b~ solvent extraction of 23 carbonaceous material treated in accordance with the in-2a vention evidence both improved quality and increased quantity 2~ over coal liquids derived from non-treated coalO For 2~ example, 0-methylation of Illinois No. 6 coal results in 27 34% solubility in pyridine (as compared to 27% for non-2~ 0-methylated coal; see Table I)o The soluble liquids from 2~ the 0-alkylated or 0-acylated carbonaceous materials have 3(; higher H/C ratio than the soluble products from untreated 31 carbonaceous materialsO
3; The thermogravimetric analysis of the 0-methylated coal 3;~ shows a significant increase in volatile organic content over 3" the untreated coal (38% versus 32%)~
3~ Subsequent to the alkylation or acylation reaction, the 3~ product may be subjected to liq~efaction. The products of 3; t~e liquefaction process are usually light gases, liquid 3~ products and a bottoms fraction. It is con~emplated ~hat all 3t or a portion of the remaining solid residue may be recycled 4~ from the liquefac~ion zone to the alkylation or acyla~ion

6~
.

l zone. Separation of the solids material can be carried out 2 by any known me~ns, such as filtration, vacuum distillation, 3 centrifugation, hydroclones, etc., and preferably by vacuum 4 distillation.
Various types of liquefaction may be employed, such as 6 solvent refining, as exemplified by the P~CO process developed

7 by the Pittsburgh and Midway Coal Company, direct hydrogena-

8 tion with or without a catalyst, catalytic or noncatalytic

9 hydrogenation in the presence of a nondonor solvent, catalytic or noncatalytic liquefaction by the donor solvent ll method, the latter being preferred particularly with the 12 presence of hydrogen during the liquefaction stepO One 13 solvent hydrogen donor li~uefaction process is described in l~ U.S. Patent 3,617,513. As used herein, liquefaction means the molecular weight degradation of coal as distinguished 16 from mere solvent extraction where essentially no molecular 17 weight degradation takes place, e.g3, extraction with 18 solvents such as benzene, pyridine or tetrahydrofuran at l9 room temperature or temperatures ranging up to the boiling point of the extractive solvent. Thus, substantial chemical 21 reaction does notoccur until the temperatures are raised 22 above about 150C, preferably above about 200C4 Liquefaction, 23 as opposed to solvent extraction, is a more severe operation, 24 maximizes light liquid yields, and involves substantial chemical reaction of the coal. Solvent extraction tends to 26 maximize heavier liquid yields, eOg., fuel oil and higher 27 boiling constituents while involving lit~le or no covalent 28 bond cleavages due to the temperatures involved9 e.gO, less 29 than 200C, preferably less than 150C, still more pre-ferably less than 115C~ Additionally, maxlmizing light 31 liquid yields allows for separa~ion of the bottoms by dis-32 tillation, e.g~, vacuum distillation, rather than by filtra-33 tion, which is used for solvent refined coals3 34 Briefly, hydrogen donor solvent liquefaction utilizes a hydrogen donating solvent which is composed of one or more 36 donor compounds such as indane, C10 - C12 tetralins, C12 ~ C13 ;

4~

1 acenaphthenes, di-~ tetra- and octahydroanthracenes and 2 tetrahydroacenaphthene, as well as ~ther derivatives of 3 partiaily saturated hydroaromatic compounds. The donor 4 solvent can be the product of the coal liquefaction process and can be a wide boiling hydrocarbon fraction, for example, 6 boiling in ~he range of about 150 to 510C~ preferably 7 about 190 to 425Co The boiling range is not critical 8 except insofar as a substantial portion of the hydrogen donor 9 molecules are retained in the liquid phase under liquefaction conditions. Preferably, the solvent contains at least about 11 30 wt. %, more preferably about 50 wt. %, based on so;vent, 12 of compounds which are known hydrogen donors under lique~action 13 conditions. Thus, the solvent is normally comprised of donor 14 a~d nondonor compoundsO
Since the donor solvent can be obtained by hydrogenating 16 coal liquids derived from liquefaction, for ex~mple, then the 17 composition of the hydrogen donor solvent will vary depending 18 upon the source of the coal feed, the liquefaction system and 19 its operating conditions and solvent hydrogenation conditionsO
Further details of a hydrogenated liquefaction recycle stream 21 are discussed in U.S. Patent 3,617,513.
22 The coal is slurried in the hydr3gen donor solvent and 23 passed t~ a liquefaction zone wherein the c~nvertible porti~n 24 of the coal is allowed to disperse or react. O-alkylation and O-acylation of the coal by the process of the invention 26 are believed to render more of the coal c~nvertible as co~-27 pared to untreated coal 28 The solvent/coal ~ , when about SOwt.% of the solvent 29 is hydrogen donor-type compounds, can range from about 0.5:1 to 4:1, preferably about 1:1 to 2:1. Preferably, the donor 31 solvent contains at least about 25% hydrogen donor compounds, 32 more preferably at least about 33% hydrogen donor compounds.
33 Operating conditions can vary widely, that i5, te~peratures 34 of about 310 ~o 540~C, preferably about 400 to 500C
pressures ~f about 300 to 3000 psig, preferably about 1000 36 to 2500 psig; residence times ~f about 5 minutes t~ 200 V~

l minutes; and molecular hydrogen input of about 0 to 4 wt.%
2 (based on DAF coal charged to the liquefaction z~ne in the 3 slurry). The primary products removed frDm the liquefaction 4 zone are light gases, liquid products and a slurry of uncon-verted coal and ash in the heavy oil. Since the liquid 6 state products contain the donor solvent in a hydrogen de-7 pleted form, the liquid can be fractionated to recover an 8 appropriate boiling range fraction which can then by hydro-9 genated and returned to the liquefaction zone as recycled~
hydrogenated donor solvent.
ll Recycle solvent, preferably boiling inthe range of about 12 175 to 425C, separated from the liquid product of the li-13 quefaction zone, can be hydrogenated with hydrogen in the 14 presesce of a suitable hydrogenation catalyst. Hydrogenation temperatures can range from about 340 to 450C pressures can 16 range from abou~ 650 to 2000 psig and space velocities of 1 17 to 6 weights of liquid per hour per weight of catalyst can be 18 employed. A variety of hydrogenation catalysts can be em-l9 ployed such as those containing components from Group VIB and Group VIII, e.g. cobalt molybdate on a suitable support, such 21 as alumina, silica, titania, etc. The hydrogenated product 22 is then fractionated to the desired boiling range and recycled 23 to the liquefaction zone or slurried with the coal prior to 24 the liquefaction zone.
The coal liquids derived from liquefaction may be further 26 processed, employing conventional refining techniques. The 27 coal liqulds will have a lower viscosity and boiling range 28 and will be produced in higher yield and will be more compa-29 tible with petroleum liquids than coal liquids produced without the 0-alkylation or 0-acylation process of the inven-31 tion. If the coal liquid is found still to be insurficiently 32 c~mpatible with certain petroleum liquids, however, the coal 33 liquid may be alXylated or acylated in a separate zone, em-34 ploying the alkylating or acylating procedures described above. The same ranges of conditions; reagents, concentra-36 tions and the like are advantageously employed to produce a 1 coal liquid more compatible with petroleum liquids.2 Light gases, such as C0, C02, H2S and light hydrocarbons 3 generated by tbe liquefaction process may be collected and 4 separated. Light hydrocarbon gases may be halogenated, such as by a free radical process, to form R'X compounds, which may 6 be recycled to the alkylation or acylation zone, thereby pro-7 viding at least a partial source of alkylating Dr acylating 8 agent.
9 Coal bottoms from the liquefacti~n zone may be recycled to the alkylation or acylation æone. Alternatively, coal 11 bottoms may be treated in a separate alkylation or acylation 12 zone. Even if not further processed in this manner, the coal 13 bottoms are more compatible with petroleum liquids and are 14 more soluble in common organic solvents than untreated coal bottoms 16 Referri~g now to he drawing, coal from storage is 17 crushed and ground to less than about 8 mesh. Sufficient 18 water is added to form an aqueous slurry of the coal which 19 is introduced via line lO to alkylation zone 11. It will be understood that an acylation zone may alternatively be employed, 21 or indeed an alkylation/acylation mixture zone. An alkylating 22 agent is introduced via line 12 and a quaternary base is intro-23 duced via line 13. The quaternary base is formed in conver-24 sion zone 14 by mixing metal base fr~m line 15 and quaternary salts from line 16. Salt MX is withdrawn via line 17.
26 It is understood that alkylation zone 11 can be one or 27 more alkylation reactions, interspersed by washing steps, 28 into each of which fresh alkylating agent and quaternary base 29 is introduced. Additionally, unreacted coal recovered from the liquefaction process can be recycled via line 32 for 31 further treatment in the alkylation zone. Alkylated coal, 32 substantially free of alkylating agent and quaternary base is 33 dried (by equipment not shown)~ and then mixed with recycle 34 solvent frDm line 38 to for~, a sDlvent/coal slurry in line 20 and ed to liquefaction zone 21 operating at a temperature bf 36 about 450C and 1500 pslg. Hydrogen is fed ~o the liquefac-Q~;~

l tion zone through line 22. A preheat furnace ~not shown) is2 often desirable to heat the slurry to reaction temperatures 3 by liquefaction.
4 Light gases, such as CO, CO2~ H2S and light hydrocarbons are removed from the lique~action zone by line 39. The li-6 quid product, in a slurry with unconverted coal, is recovered 7 in line 23 and flashed in drum 24 to reduce the pressure, with 8 light gases and Light hydrocarbons being flashed off in line 9 25 and an oil/coal slurry being recovered in line 26. The light hydrocarbons from line 39 can be treated by conventional ll means to re~ove CO2 and H2S and then sent to a c3nventional 12 steam refor~ing furnace where the hydrocarbon gases are re-13 formed to produce hydrogen for use in the process, such as in 14 line 22 (and in line 34). The former, 42, can also be used to handle off gases from the pipestill 27 (line 28) and fraction-16 at~r 36 (line 37). A portion of the light gases may be halogen-17 ated (apparatus not shown) and the alkyl halides fDrmed may be 18 used as a partial or total source of alkylating agent in line lg 12.
The product of line 26 is then tr~ated in a fractiDnator 21 27 which can be an atmospheric or vacuum pipestill or both.
22 Light gases are removed overhead in line 28 while a recycle 23 solvent stream is removed via line 29 for treatment in sol-24 vent hydr~treater 33. Liquid product for upgrading by, e.g. 9 catalytic cracking, is recovered in line 3~. A product con-26 taining the residuum and unconverted coal (botto~s) is ta~en 27 off by line 31, a portion of which can be recycled via line 28 32 to the alkylation zone, or treated in a separated alkyl-29 atiOn zone and then recombined with the feed to the lique-faceion zone. In a balanced process, so~e or all or the 31 bottoms can be sent to hydrogen manufacture via line 41 to 32 make hydr~gen for use in the liquefaction zone and the sol-33 vent hydrotreater.
34 Recycle solvent is catalytically hydrogenated in hydro-treater 33, hydrogen being supplied in line 34, over a 36 catalyst such as cobalt molybdate on an alumina support.

1 Hydrotreated product is recovered in line 35 and fraction-2 ated in fractiDnator 36 frDm which recycle hydrogen donor 3 solvent of the desired boiling range is recovered in line 4 38 and recycled to line ~0 to slurry alkylated coal. Addi-tional liquid prodtlct is recovered in line 40 and may bP
6 subjected co further upgrading. Any light gases formed 7 during hydrotreating can be rem~ved via line 37.
8 Exam~le 1 - Phase Transfer Noncatalyzed Alkylation 9 Rawhide sub-bituminous coal was treated as f311OWS:
A slurry of 30.8g Rawhide coal (-80 mesh) and 300 mmoles 11 (free base) of tetrabutylammonium hydroxide (75% in aqueous 12 solution) were mixed together at ambient temperature and 1 13 atm pressure for a few minutes. Tetrahydrofuran (200 ml) and 14 500 mmoles ~f n-heptyliodide were than added and the reaction mixture was stirred for nearly three hours. The colorless 16 water layer was then separated and fresh water added to was~
17 out any residual quaternary salt from the organic phase 9 which 18 contained the 0-alkylated coal. The washing was continued un-l9 til the pH of the wash water was neutral and no precipitate formed when silver nitrate was added to the wash water. (A
21 byproduct of the alkylation was tetrabutylammonium iodide, 22 which reacted with the silver nitrate to give a precipitate 23 of AgI). The excess heptyliodide, water and THF were removed 24 by vacuum distillation at 100-110C. The alkylated coal was then analyzed. Infrared analysis revealed essentially com-26 plete eliminati~n of the hydroxyl band (3100-3500 cm 1), as 27 well as incorporation of thb alkyl ether funcit~nality ~lOOn-28 1200 cm ) and the ester e&~ functionality (1700-1735 cm ).
i 29 Exam~l_s 2 7 - Phase Transfer NonCatalyzed Alkylati?n The following runs were made, employing the procedure set 31 forth in Example 1. In each reaction, the quaternary base 32 was tetrabutylammonium hydroxide. The base was present in a~
33 least stoichiometric amount of the number of acidic protons 34 on the coal sample in the case of ~awhide and 2:1 in the case 3s Illinois No. 6.

TABLE II
2 PHASE TRANS~ER NONCATALYZED REACTIONS Reaction 3 Example Coal(l) Rlx(2~ Time, hr.
4 2 Illinois #6 ~80/100) CH3I, 200%
3 Illinois #6 (-80) C4HgI~ 200% 3 6 4 Illinois #6 (80/100) C7~1sI, 200% 3 7 5 Rawhide (80/100) CH3I, 200%
8 6 Rawhide (80/100) C41~9I, 200% 3 9 7 Rawhide (80/100) C7~1sI, 200% 3 Notes: (1) Mesh size is indicated in par~ntheses ll (2) Weight percent relative to coal 12 Example 8 - Phase Transfer Catalyzed Alkylation 13 Illinois No. 6 coal was treated as foLlows:
14 Twenty grams of Illinois No. 6 coal (80/100 mesh), 50ml of a 50% aqueous NaOH solution, 150 ml of toluene, 70 mmoles 16 f CH3I and lg of tetrabutylammonium chloride were mixed to-17 gether under a nitrogen atmosphere (the order of addition was 18 not important). After five days, the aqueous layer was sep-l9 arated and the organic phase washed with water until the un-reacted sodium hydroxide and catalyst were extracted out of 21 the toluene. The toluene, water and excess iodomethane were 22 removed under vacuum at 100C~ The O-alkylated coal was then 23 analyzed. Infrared analysis revealed essentially complete 24 elimination of the hydroxyl band (3100-3500 cm 1), as well as 25 - incorporation of the alkyl ether functionality (1000-1200 cm l) 26 and incorporation of the ester carbonyl functionality (1700-27 1735 cm 1).
28 Examples 9-35 - Phase Transfer Catalyzed Alkylation 29 The ~ollowing runs were made employing the procedure set forth in Example 8.

1:145DQt~
- 19 - .~ !
o ~ U~S
o r~ C~l ~
'O ~ ~ 0 C
~! ~ v~
o o ~ o - ~ ~
~ ~ E
Y~ _ ~1 ^ ^ ~ ~ E
~ ~ ~ O O ~ ~1 o~
_~ ~ ~ ~ o ~ ~ ~ 1~ ~ E ^ ~ o~ ;~
x ~ o ~ ~ O~ e ~ cO ~ ~ 0 O ~ ~
000~ E~i ~0 0~51 r~ ~co~ C OOoaO~OOOO
~: Ou~ O OCO ~ ~0 0 ~ I ~ ~SO~O~
- ~1,~ 2 r-l ~ E h 5~ D r-l ~ E a o - ^ ^ -~ ~ O _ c e~ O O ~~ ~ ~ e~
S C~ h (~~ J S r_l ~e~ I ~ ~ e~ ~ ~J ~ ~

V~ C
Z _~
O ~ 0~ ~ ~O ~ ~ ~O ~ O ~;~ ~0 ~ ~ ~ ~ ~a~
~ c~ ~ ~ ~ O O O O O O O O O O O O C~l O O O ~ O O O O e~l ~O
C~ ~rl O O O U~ U~ e~
¢ ~ U~ ~ ~
ts~ r3 _ ~ _ ~ ~ _ ~ ^ _ _ _ _ ~ _ _ _ _ ~ _ ~ ~ ~ ~ Z
1~ :~ ------OOOOOOOOOOOOOOOOOO~OOCOO
~:~ Y ~ ~ 2 ~ ~ Z Z 2~ Z Z ,_ Z Z Z--Z Z Z ~: ~ ~ Z :~ Z Z ~
¢
~ ~ _ C
::~ ~ ~
_ ~ ~ ~ ~ ~ ~ ~ ~ ~ o~ ~ ~ ~ ~ ~'~ ~ ~ ~ o _ ~ OOOOOOOOOOOOOo~O~OO OOO~o~o~
cn ~1 . Ll Z eTJ ~ ~ ~ ^ ~ ~ C~ ,C
E-~
Ll C~ C~ e~ ~ ~ IIIJ aJ e~ rl) tl~ rJ) Q) ~ Q~ C~ n o~ ~ ~ a~ Ql ~ o~
~1 C C C C C C C C C C C C C C C C C C ~I C~ C C C C ~ E
,rf~ ~) ~ a~ ~,J e~ rJ~ C~ r~ ~ a.) ~ C S ~ ~
_ r--lr-l ~i r--t r~ r--t r-l r~l r--l r,~l r~ r--I r~ ~ r--f ~_ r--~ r--i r--l r. -i ~1 e~l r--I r--I ~I r- r--t ~ ,C C a:l C) G OO O O O O O O O O O O O O O O O O ~ ~ O O O O _ C-- LJ O O u U~ e ' é~ é-~ é-~ e ~ ~ é~ é~ é~ ~ E~ ~ é~ ~ é~ E~ F~ X X X ~ ~ é~ er~ e~ ~ e~ e~ O
,~ rJ
O
O '~ '~ O
_,~ C ) ?
I ~ e~ -r j <1 ~ O O O C~ ~ c O O O
~_ o o o o o ~ o o ~ ~ o o _ r--I O ro O O O O O C~ O O O o O o ~ 0 O 0 O O O O ~ O O ~ ~ ~ ~ L~
_r t~ ~1 e~ r--~ O O O O O r--l r~ O C~ ~l r--~ r--l c~ e ~ c~ e cO C O e~ O O
r~l I I I I I r--l r--l e~l --i r I I I r--t r~ I I I I I c~ e~ e~ ~1~ v v e~l O ~ ~ ~ ~ ~/ O ~e r~ ~ O ~ O ~ O ~) ~ ~D ~ 5 t-a e ,v v ~ ~ y =;ee; e v v ~ ee ;~ ~e ~e~e~ ~e ;~e~ e ~e ~ ~ J~J u ~ I
e~ I C C C
r~ r-l r-~ _~ O O O O O r~l r~~ 0 0 X r-l r~ r~ r~l r~~ r~l r~l r ~ r-l ~r/ r-l r~ ~ rJ
r~ r~l ~ r~ r~l r~ ~ r~l r~~ r~~ r--l ~ r--l r--~ r~ r-l r~~ e~~ ~ r~
r~l ~ ~1 _ 3 ~ ~ 3 ~ ~ ~ ~' `~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 1~
:~1 r O. r~
~1 IJ LJ
r~ _ _ c a~ o ~ e~l ~ O ~ O ~ c~ e~) ~ ~
X . _ _ u~
-: ~
~ C~J ~ ~ en ~ o ~ ei~ C~ O _l c~ cr~ ~ ~ ~o r~ tD a~ C r--~ e_ ~ c~

1 Exam~le 36 - L~ faction of Alkylated Coa~
2 Three coal samples were liquefied; each of these samples 3 were run in duplicate with excellent reproducibility. The 4 liquefaction was carried out at 425C using a two-fold excess of te~ralin in a hydrogen atmosphere, The apparatus used 6 was a tubing bomb unit (a batch liquefaction reactor), The 7 residence time of the sample was two hours. One sample pair 8 was Illinois No. 6 coal which was untreated. Another sample 9 pair was Illinois No. 6 coal which was base treated, then acidified tBWlacidified), This second pair represents the 11 coal used in the phase transfer alkyla~ion or acylation ex-12 cept that no alkylating or acylating agent was used. It was 13 a blank run sample in order to ensure that no other component 14 of the phase transfer alkylation reaction conditions actually caused some effect on the liquefaction. The third sample pair 16 was a phase trznsfer reactant O-perdeuteromethylated Illinois 17 No, 6 coal with 4.5 CD3 groups incorporated in the coal me~rix 18 for every 100 carbon atoms p~esent. The percen~ conversion 19 (on a dry mineral matter free basis~ for each liquefaction was calculated by the following equation:
21 % Conversion (~MMF) - ~100 (weight of charge-22 weight of residue)~/~weight of charge/ (100 -23 mineral matter3/100]
24 The values found are summarized in Table IV below~
TABLE IV

27 Sample% Conversion Reproducbility 28 Illinois No. 6 Coal 54.5 ~ 1,5%
29 BW/Acidified Illinois 56.8 ~ 5.~0 No. 6 Coal 31 O-Perdeute~omethylated 74.S + O.770 32 Illinois No. 6 Coal 33 Mass spectrographic analysis of the gases produced in 34 the three different liquefaction runs revealed some impor~ant information. First, only in the case of O-perdeutheromethy-36 lated Illinois No. 6 was there no water produced. This, of 06~

l course, means that there was eficient use of hydrogen. In-2 stead, this O-methylated coal produced a considerable in-3 crease in quality of gaseous hydrocarbons: that is, substan-4 tially no C02, H2S, etc. was found. Methane (found with iso-topic label), for example, was at a level of 3~0~ above the 6 other two sample types. In contrast, the untreated and the 7 BW/acidified coal gave results very similar to each other.
8 ~uch hi&her levels of e~hane, propane and butane were also 9 observed in the liquefaction of the perdeuteromethylated coal.
However, the total quantity of gas produced in all three ll cases was about the same.

Claims (14)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A method for improving properties of solid, naturally-occurring carbonaceous material which method comprises contacting the carbonaceous material with a solution comprising:
(a) at least one quaternary base represented by the formula R4QOR" where each R is the same or different group selected from the group consisting of C1 to about C20 alkyl and C6 to about C20 aryl; Q is nitrogen or phosphorus;
and R" is selected from the group consisting of hydrogen, C1 to about C10 alkyl, aryl, alkylaryl, arylalkyl and acetyl;
and (b) at least one compound represented by the formula R'X where R' is a C1 to C20 alkyl or acyl group and X-is selected from the group consisting of halides, sulfates, bisulfates, acetates, and stearates; wherein X is attached to a primary or secondary carbon atom.

2. The method of claim 1 wherein R" is a C1 to C4 alkyl group or hydrogen, R is the same or different C1 to C6 alkyl group, R' is a C1 to C4 inert hydrocarbon group, and X is selected from the group consisting of chlorine; bromine and iodine.

3. The method of claim 2 wherein X is chlorine, R' is a methyl group, and Q is nitrogen.

4. The method according to claim 1, 2 or 3 wherein the amount of quaternary base ranges from about a stoichiometric amount to about 10 times the total number of acidic sites on the carbonaceous material.

5. The method of claim 1, 2 or 3 wherein R'X is present in at least a stoichiometric amount relative to the number of acidic sites on the carbonaceous material.

6. The method of claim 1 wherein a quaternary salt represented by the formula R4QX is reacted with an alkali or alkaline earth metal base represented by the formula MOR" to form the corresponding quaternary base, wherein M is an alkali or alkaline earth metal.

7. The method of claim 1 wherein the reaction is carried out catalytically.

8. The method of claim 7 wherein the amount of quaternary salt is a catalytic amount ranging from about 0.05 to 10 wt. % of the carbonaceous material.

9. The method of claim 6 wherein the quaternary base is formed separate from the alkylation or acylation reaction.

10. The method of claim 6 which is repeated at least once.

11. The method of claim 1 wherein the carbonaceous material is coal.

12. The method of claim 11 wherein the contacted coal is subjected to a liquefaction process.

13. The method of claim 12 wherein at least a portion of the contacted coal is liquefied at temperatures ranging from about 310°C to about 540°C and pressures of about 300 to about 3000 psig in the presence of a hydrogen donor solvent and/or molecular hydrogen wherein the boiling point of the hydrogen donor solvent is from about 150°C
to about 510°C.

14. Coal wherein the hydrogen atom of substantially all of the hydroxyl or carboxyl groups of the coal have been replaced with a group selected from the group consisting of C1 to C20 alkyl and acyl groups.