LIQUEFACTION PROCESS

Field of the Invention

The present invention relates to a liquefaction process, in particular to a liquefaction process for solid carbonaceous materials, such as for example sub-bituminous coal and lignite.

Background of the Invention

There are several processes which may be employed to produce hydrocarbonaceous liquids from solid carbonaceous materials, such as for example coal, that are generally classified as either indirect or direct liquefaction. Indirect liquefaction involves gasification of the carbonaceous material followed by chemical processing at high pressure to yield a variety of liquid hydrocarbons. Direct liquefaction involves hydrogenation of the carbonaceous material under elevated temperatures and pressures to form a liquid plus a solid residue. In general, direct liquefaction demonstrates higher thermal efficiency and potentially lower processing costs than indirect liquefaction.

Direct liquefaction requires addition of hydrogen to the carbonaceous material so that the H/C ratio is increased to a range where the resulting product is a hydrocarbonaceous liquid. This process is frequently referred to as hydroconversion. The liquids produced typically may contain about 70% hydrocarbons (hydro- and polyhydroaromatics) , 8% heterocyclic compounds (mostly ethers) , 10% monophenols (predominantly less than 10 carbon atoms) and 12% polyphenols and basic nitrogen compounds. Of these classes of compounds, about 30-50% of

the total liquid may be composed of the following compounds: naphthalene, methylnaphthalene, biphenyl, diphenyl ether, phenathrene and/or anthracene, and pyrene . A substantial portion of the basic nitrogen compounds present may be quinolines. It is expected such hydrocarbonaceous liquids may be suitable for further processing in a similar manner to crude petroleum products, or as a heavy fuel oil for use in boilers and such like. Hydroconversion reactions rely on low temperature pyrolysis processes which occur in a temperature range between 350°C and 550 ⁰ C. Pyrolysis reactions include loss of hydroxyl groups, dehydrogenation of some aromatics, cleavage of methylene bridges, and rupture of alicyclic rings, all leading to generation of free radical species which participate in rapid secondary reactions . The products of these reactions are very dependent upon the availability of hydrogen by means of free hydrogen or a hydrogen donor solvent, and the presence of catalysts.

The present invention seeks to overcome at least some of the above mentioned disadvantages.

Summary

In its broadest aspect, the invention provides a process for producing a hydrocarbonaceous liquid from a solid carbonaceous material .

In a first aspect, the present invention provides a process for producing a hydrocarbonaceous liquid from a solid carbonaceous material comprising the steps of : a) providing a slurry of the solid carbonaceous material, a catalyst, and a hydrogen donor solvent and reacting the slurry with supercritical carbon

dioxide whereby at least a portion of the solid carbonaceous material is converted to the hydrocarbonaceous liquid; and, b) recovering the hydrocarbonaceous liquid.

The present invention seeks to provide a simple relatively low cost process for efficient liquefaction of carbonaceous materials, in particular brown coal and lignite, into a hydrocarbonaceous liquid that can be used as a feedstock for the production of fuel or fuel supplements .

In one embodiment of the invention the reaction is performed at a temperature in a range of about 350°C to about 500° C and a pressure in a range of about 500 psi to 3000 psi. In particular, the reaction can be performed where the temperature is in a range of about 350° C to about 380° C and the pressure is in a range of about 500 psi to 1500 psi.

In another embodiment of the invention prior to step (a) , the solid carbonaceous material is pre-treated by providing a mixture of the solid carbonaceous material, the catalyst, and a diluent and reacting the mixture with supercritical carbon dioxide. The hydrogen donor solvent is then added to the pre-treated mixture to provide said slurry and the hydroconversion reaction of step a) is performed.

Advantageously, the pre-treatment of the solid carbonaceous material as defined above improves dispersion of the catalyst in the solid carbonaceous material and swells the particles of the solid carbonaceous material. In this way, the increased surface area of the pre-treated particles and dispersion of the catalyst improves the availability of solid carbonaceous material in the

subsequent hydroconversion reaction thereby resulting in shorter reaction times and increased yields.

Accordingly, in a second aspect there is provided a process for improving the dispersion of a catalyst in a solid carbonaceous material comprising providing a mixture of the solid carbonaceous material, the catalyst, and a diluent and reacting the mixture with supercritical carbon dioxide .

In a third aspect, there is provided a process for swelling particles of solid carbonaceous material comprising treating the particle of solid carbonaceous material with supercritical carbon dioxide.

Description of the Figures Accompanying the Description

Figure 1 is a direct injection gas chromatography mass spectrograph (GCMS) of a THF soluble liquid obtained from the reaction products of the process for producing hydrocarbonaceous liquids from a solid carbonaceous material in accordance with the present invention and as described with reference to the Example;

Figure 2 is an enlargement of the area of Figure 1 marked Enlargement 1;

Figure 3 is an enlargement of the area of Figure 1 marked Enlargement 2; and

Figure 4 is an enlargement of the area of Figure 1 marked Enlargement 3.

Detailed Description of Preferred Embodiment

The present invention relates to a process for producing a hydrocarbonaceous liquid from a solid carbonaceous material wherein the solid carbonaceous material is subjected to a hydroconversion reaction with a hydrogen donor solvent and super critical carbon dioxide in the

presence of a catalyst to produce hydrocarbonaceous liquid. The hydroconversion reaction is performed at elevated temperature and pressure .

Preferably, prior to performing the hydroconversion reaction the solid carbonaceous material is pre- treated with super critical carbon dioxide to swell the particles of solid carbonaceous material. Even more preferably, prior to performing the hydroconversion reaction the solid carbonaceous material is mixed with a catalyst and a diluent, and the mixture is treated with super critical carbon dioxide to swell the particles of solid carbonaceous material while at the same time improving the dispersion of the catalyst within the swelled particles.

In general, the process of the present invention can be used to convert any solid carbonaceous material to hydrocarbonaceous liquids. Suitable examples of solid carbonaceous material include, but are not limited to, coal, biomass, solid organic waste material such as tyre refuse, shale oil, tar sand bitumen and the like, and mixtures thereof. The invention is particularly useful in the hydroconversion of coal and may be used to liquefy any of the coals known in the prior art including bituminous coal, sub-bituminous coal, lignite, peat, brown coal and the like.

The particle size or particle size range of the solid carbonaceous material is not believed to be critical to the invention, although small particle sizes are preferred wherein the surface area to particle diameter ratio favours increased hydroconversion reaction rates. In a preferred embodiment of the invention the solid carbonaceous material is ground to a particle size of 200- 300 mesh.

After sizing the solid carbonaceous material particles, a slurry of the solid carbonaceous material, a hydrogen donor solvent, and a catalyst is prepared. Typically, the ratio of hydrogen donor solvent to solid carbonaceous material will be within a range of about 1:1 to about 5:1 on a weight basis. The weight basis is not necessarily calculated on a moisture- free basis with respect to the solid carbonaceous material as will be explained later, and a larger excess of hydrogen donor solvent may only be required under some circumstances to ensure that the slurry is sufficiently fluid to be readily transported through pipework and the like .

The hydrogen donor solvent is one suitable for the hydroconversion of solid carbonaceous materials to hydrocarbonaceous liquids. The hydrogen donor solvent may include mixtures of one or more hydrogen donor compounds . Illustrative examples of hydrogen donor solvents include, but are not limited to, indanes, the dihydronaphthalenes, the Ci ₀ -Ci ₂ tetrahydronaphthalenes, the hexahydrofluorenes, the dihydro-tetrahydro-hexahydro- and octahydropheanthrenes, the Ci ₂ -Ci ₃ acenaphthenes , the tetrahydro-hexahydro-and decahydropyrenes , the di-tetra- and octohydroanthracenes and other derivatives of partially saturated aromatic compounds. The hydrogen donor solvents may also be selected from distillate fractions of hydrocarbonaceous liquids derived from hydroconversion of carbonaceous materials, in particular coal oils derived from coal liquefaction processes. It will be appreciated that the solid carbonaceous material may be soluble, at least in part, in the hydrogen donor solvent, in particular under the process conditions of the hydroconversion reaction.

The catalyst is one suitable for the hydroconversion of solid carbonaceous materials to hydrocarbonaceous liquids, in particular a hydrogenation catalyst. The catalyst may

include mixtures of one or more catalysts or mixtures of one or more catalyst precursors which may be converted to an active hydrogenation catalyst under the hydroconversion reaction conditions of the present invention. Illustrative examples of suitable catalysts include those comprising one or more Group VIII metals, one or more Group VI metals, and combinations of one or more metals from Group VIII and Group VI, in particular iron, molybdenum, cobalt, nickel, chromium, tungsten and the noble metals including platinum, palladium, iridium, osmium ruthenium and rhodium. Such catalysts may be supported on an inert matrix formed from alumina, silica alumina or a similar support. Other illustrative examples of suitable catalysts include inorganic metal compounds such as metal halides, oxyhalides, oxides, sulfides, heteropoly acids (eg. phosphomolybdic acid and molybdosilic acid) and the like; metal complexes such as metal chelates, metal complexes of organic amines, metal complexes of organic carboxylic acids, and the like,- and organometallic compounds, all of the foregoing having one or more metals selected from the group consisting of Group VIII and Group VI metals as described above.

In general, the ratio of catalyst to solid carbonaceous material in the slurry will be within a range of about 1 to 20% w/w. The catalyst may be dissolved or dispersed in a suitable diluent prior to preparing the slurry, and may be converted in situ to the active catalyst species as the slurry is heated to hydroconversion temperatures. In general, the diluent will be selected on the basis of the solubility of the catalyst therein. Illustrative examples of the diluent include, but are not limited to, water, methanol, ethanol, acetonitrile, and aprotic solvents such as dimethylsulfoxide and dimethylformamide, and mixtures of one or more thereof.

The slurry is prepared by dispersing the sized solid carbonaceous material in the hydrogen donor solvent together with the catalyst. As mentioned previously, in the preferred embodiment of the invention, prior to performing the hydroconversion reaction, the sized solid carbonaceous material undergoes a pre-treatment to swell the particles of the solid carbonaceous material and improve the dispersion of the catalyst in the particles. Where pre-treatment has already occurred the slurry is prepared by dispersing the pre-treated solid carbonaceous material in the hydrogen donor solvent in the desired ratio, and there is no necessity to mix the catalyst into the slurry as it has already been dispersed in the solid carbonaceous material during the pre-treatment reaction.

The hydroconversion of the solid carbonaceous material to hydrocarbonaceous liquid is accomplished by reacting the slurry in the presence of supercritical carbon dioxide under conditions where the temperature is in a range of about 350° C to about 500° C and the pressure is in a range of about 500 psi to 3000 psi. Preferably, the reaction is performed where the temperature is in a range of about 350° C to about 380° C and the pressure is in a range of about 500 psi to 1500 psi.

Typically, the hydroconversion reaction will be performed in a pressure vessel adapted to maintain conditions under which supercritical carbon dioxide can be delivered to the reaction mixture and maintained. Supercritical carbon dioxide refers to carbon dioxide that is in a fluid state while also being at or above both its critical temperature (31.1 °C) and pressure (73 atm) . Hydroconversion of the solid carbonaceous material to a hydrocarbonaceous liquid is performed at the above described conditions for a period in a range of about 15 minutes to 480 minutes. In general, the hydroconversion of the solid carbonaceous

material may be accomplished in a batch or a continuous operation.

While not wishing to be bound by theory, the inventors opine that the relatively mild temperature conditions and fast reaction rates observed in the hydroconversion reaction of the present invention are obtainable by virtue of the use of supercritical carbon dioxide which facilitates increased penetration of the hydrogen donor solvent in the pores of the particles of the carbonaceous material .

The hydroconversion of solid carbonaceous material in accordance with the present invention produces three phases: a gaseous product, the hydrocarbonaceous liquid, and a solid residue product, each of which may be separated into the respective phases by methods well known and understood to the person skilled in the art. In general, the hydrocarbonaceous liquid may be recovered by distillation, centrifugation, filtration, and the like. Both the hydrocarbonaceous liquid and the solid residue product may be contaminated with catalyst or spent catalyst, and known techniques may be used to separate the catalyst or spent catalyst from the reaction products.

The inventors have found that the pre-treatment of sized solid carbonaceous material with supercritical carbon dioxide in the presence of the catalyst results in several advantages which assist the performance of the subsequent hydroconversion reaction described above.

Firstly, the supercritical carbon dioxide is very efficient at penetrating the porous structure of the sized particles of solid carbonaceous material and swelling the sized particles, thereby increasing the surface area of the particles and its availability to the subsequent hydroconversion reaction.

Secondly, the pre-treatment with supercritical carbon dioxide improves the dispersion of the catalyst into the sized particles which, in turn, improves the efficiency of the hydroconversion reaction.

Further, the inventors have observed that the presence of water in the pre-treatment reaction demonstrates no deleterious effects and may even assist in catalyst dispersal. Under supercritical conditions carbon dioxide shows similar solvent properties to hexane, a solvent in which the catalysts of the present invention show little or no solubility. It is therefore important to dissolve or disperse the catalyst in a diluent, such as water, in the mixture of solid carbonaceous material and the catalyst prior to pre-treatment to ensure effective dispersal of the catalyst in the solid carbonaceous material. The advantages arising from tolerating a polar solvent as the diluent includes the fact that during pre- treatment, inorganic impurities (eg. sulphur, nitrogen, sodium, calcium, etc) are transferred from the sized particles of carbonaceous material into the diluent. Additionally, and in particular when the diluent is water, there is no necessity to subject the solid carbonaceous material to a drying process to remove water. This feature of the present invention is advantageous in comparison with prior art processes for the liquefaction of carbonaceous material where it is typically essential to remove all surface moisture and at least some inherent moisture from the carbonaceous material prior to commencing hydroconversion reactions. The drying process required in prior art processes adds significantly to the overall capital and operating costs and releases significant amounts of carbon dioxide to the atmosphere.

Accordingly, after sizing the solid carbonaceous material particles, the solid carbonaceous material may be pre- treated by first forming a mixture of the solid

carbonaceous material, a catalyst and the diluent in which the catalyst is at least partially soluble. Typically, the ratio of catalyst to solid carbonaceous material will be within a range of about 1 to 20% w/w, as described above .

The mixture is placed in a pressure vessel adapted to maintain conditions under which supercritical carbon dioxide can be delivered to the reaction mixture and maintained. Pre-treatment of the solid carbonaceous material in the presence of supercritical carbon dioxide is performed under conditions where the temperature is in a range of about 50 ⁰ C to about 250 ⁰ C and the pressure is in a range of about 500 psi to 3000 psi for a period in a range of about 60 minutes to 480 minutes. In general, the pre-treatment of the solid carbonaceous material may be accomplished in a batch or a continuous operation.

Once the pre-treatment has been completed, a desired volume of hydrogen donor solvent as described above may be directly added to the pre-treated mixture in the pressure vessel, and the contents thereof may then be placed under conditions where the hydroconversion reaction in accordance with the present invention proceeds as described above.

The invention will be illustrated in greater detail with reference to the following examples .

Example 1

Brown coal (Loy Yang, Table 1) was ground to fine (approximately 300 mesh) particles.

Pre-swelling and Catalyst Dispersal

Coal (50 g) was mixed with 10 g ferric chloride (Sigma) and 50 mL of water and the resulting slurry was stirred at room temperature for 2 hours. The slurry was then placed in a 600 mL PARR (5500 series) stirred reactor. The reactor was sealed and pressurized to 800 psi with carbon dioxide gas . The reactor contents were then heated to 80 ⁰ C (as measured by an internal temperature sensor) for 3 hours. The reactor pressure reached approximately 1000 psi during the reaction.

Donor Solvent Extraction

The pre-swollen coal was then mixed with 200 mL tetralin (1, 2, 3 ,4-tetrahydronaphtalene) and placed in a 600 mL PARR (5500 series) stirred reactor. The reactor was sealed and pressurized to 100 psi with carbon dioxide gas. Following leak testing, the reactor was then heated up to 375 ⁰ C. The reaction was allowed to proceed for 30 minutes at 375 ⁰ C with stirring. The maximum reaction pressure increased to 2650 psi. The reactor was then cooled to room temperature and opened following pressure release. The coal liquefaction products were then analysed.

Determination of THF insolubles

The contents of the reactor were poured into a large beaker and washed several times with THF to remove any residual coal products. The THF washes were added to the beaker. The coal liquefaction products were then filtered through a Buchner funnel with a Whatman's No. 5 filter paper (2.6 μm pore) using a water pump. The filter paper was washed with excess THF to ensure all coal liquids were collected. The filter paper was then dried in an oven at 110 ⁰ C until its weight remained constant (ca. 30 min.) and then weighed. The filter was then washed with concentrated hydrochloric acid, then rinsed with water and dried at 110 ⁰ C until a constant weight (ca. 1 hour) . The

filter was then reweighed. The residual solid (12.0 g) on the filter paper is the THF insoluble coal fraction.

Percentage coal (maf) soluble in THF = (50-12) x 100 50

= 76%

The coal liquids filtrate was placed in a round bottomed flask attached to a rotary evaporator and the solvent was removed by evaporation under reduced pressure.

Determination of hexane insolubles (asphaltenes and pre- asphaltenes)

A portion of the coal liquids filtrate isolated above (5 g) was weighed and mixed with 200 mL of hexane. The mixture was allowed to stand at room temperature for 30 minutes, after which it was filtered through a Bchner funnel with a Whatman's No. 5 filter paper using a water pump. The residual solid (0.2 g) on the filter paper was the hexane insoluble fraction.

Weight of coal liquids sample added to hexane = 5 g Weight of insolubles on filter paper = 0.2 g Percentage of hexane solubles in 5 g coal liquids = (0.2/5.0) X 100 = 4%

Therefore the combined weight of pre-asphaltenes and asphaltenes in the coal sample is 2 g.

Determination of toluene insolubles (pre-asphaltenes)

The toluene insolubles were determined using the same procedure as used for the hexane insolubles, except that toluene was used instead of hexane.

Weight of sample added to toluene = 5 g Weight of insolubles on filter paper = 0.22 g Percentage of toluene solubles in 5 g coal liquids

= (0.22/5.0) x 100

= 0.44%

Therefore the weight of pre-asphaltenes in the coal sample is 0.22 g, and the weight of asphaltenes in the coal sample is 1.78 g.

Results

The pre- treatment of coal with supercritical carbon dioxide and water at 80 ⁰ C and 1000 psi facilitates swelling of the coal particles to about 1.5 times in volume. The appearance of the coal remains as very fine discrete particles.

About 36% of the coal is converted into hexane soluble liquids (oils) .

Mass Spectroscopy Analysis

A sample of the THF soluble extract was analysed by direct injection gas chromatography mass spectrometry (GCMS) .

The resulting analysis (Figures 1 to 4) shows two major

peaks that represent the solvents used in the process

(i.e. THF and tetralin) , however there are a number of peaks representing higher mass molecules (40 to 70 time range) that are coal liquefaction products. Compounds in the coal liquefaction products which were identified by

GCMS are listed in Table 2.

It is to be understood that, although prior art use and publications may be referred to herein, such reference does not constitute an admission that any of these form a part of the common general knowledge in the art, in Australia or any other country.

For the purposes of this specification it will be clearly understood that the word "comprising" means "including but not limited to", and that the word "comprises" has a corresponding meaning.

Numerous variations and modifications will suggest themselves to persons skilled in the relevant art, in addition to those already described, without departing from the basic inventive concepts . All such variations and modifications are to be considered within the scope of the present invention, the nature of which is to be determined from the foregoing description.

Table 1

Loy Yang Coal Quality Distribution

Coal: Loy Yang 1980 Mine Area

Weighted 5% 50% 95%

Average

Proximate Analysis

Moisture, % 62.7 59.2 62.7 65.9

Ash, %db 1.4 0.8 1.2 3.9

Volatiles, %db 49.1 51.6 54.3 51.3

Fixed Carbon, %db (Note 1) 49.5 Not applicable

Elemental Analysis, %db

C 68.4 65.6 68.8 70.7

H 4.9 4.6 4.9 5.2

O by Diff (Note 2, Note 3) 24.6 Not applicable

N 0.5 0.4 0.5 0.6

S (total) 0.4 0.2 0.3 0.7

Specific energy - Gross Dry MJ/kg 26.6 25.1 26.7 27.8

Minerals and Inorganics, % db

SiO2 0.34 0.02 0.10 1.41

AI2O3 0.38 0.02 0.16 1.32

K2O Trace

TiO2 Trace

FeS2 Trace

Fe total 0.13 0.05 0.12 0.25

Fe np 0.13 0.05 0.12 0.25

Ca 0.04 0.01 0.03 0.12

Mg 0.08 0.03 0.06 0.17

Na 0.11 0.04 0.08 0.33

Cl 0.14 0.05 0.10 0.37

Total Mineral (& Inorganic) Matter 1.2 J Not applicable

Calculated Ash (Note 2) 1.5

Measured Ash 1.4 0.8 1.2 3.9

Ash Composition, % in Ash (Note 2)

SiO2 22.5

AI2O3 25.1

K2O 0.0

TiO2 0.0

Fe2O3 12.3 J Not applicable

CaO 3.7

MgO 8.8

Na2O 9.8

S03 17.9

Sum of Components 100.0

Inorganic Analysis, % in dry coal

Si 0.16 0.01 0.05 0.66

Al 0.19 0.01 0.08 0.65

K Trace

Ti Trace

Fe 0.13 0.05 0.12 0.25

Ca 0.04 0.01 0.03 0.12

Mg 0.08 0.03 0.06 0.17

Na 0.11 0.04 0.08 0.33

Cl 0.14 0.05 0.10 0.37

Notes:

[1] Fixed carbon is a misleading parameter to quote for brown coals, as it is the difference balance after deducting the volatile matter and ash contents from the dry coal weight. However, there is no ash in the coal, only minerals and inorganics, the ash is the residue after combustion of the organic coal substance and includes oxides of the inorganics in the coal and some sulphation of these oxides.

[2] Parameters which are determined by difference from, or summing of, measured coal parameters can be determined on individual coal sample analyses or weighted average analyses, but cannot logically be determined for the percentile distribution data. Parameters particularly effected by this constraint are marked na (not applicable), and include the fixed carbon and oxygen figures, the calculated ash, total (sum of) minerals and inorganics and the ash composition data.

[3] The Oxygen by difference figure is based on the balance after summing the individual organic elements and the minerals and inorganic components. The following table illustrates the realtively small effect of using the ash content instead of the total minerals and inorganics (see Note 1 in relation to there being no 'ash' in the coal) to determine the oxygen by difference. The main table uses the Minerals and Inorganics figure as more accurately estimating the organic oxygen in the coal

Table 2 - Identification of Coal Liquefaction Products by GCMS

07-178 Sample B lab no. 0717802W.D Tentative Identification RT %match area

Furan, tetrahydro- 14.1 91 292622 Xylene 26.8 94 609 Phenol 29.8 91 2287

1 H-lndene, 2,3-dihydro- 31.9 81 987 Phenol, 2-methyl- 32.3 97 460 Benzene, butyl- 32.5 91 831 Naphthalene, decahydro- 32.6 97 15920 Phenol, 3-methyl- 32.8 97 1909 E-1-phenylbutetene 33.4 95 683 1 H-lndene, 2, 3-dihydro-1 -methyl- 33.5 93 6487 Naphthalene, decahydro-, cis- 34.0 99 34167 3-Methylene-bicyclo[4.3.0]nonane 34.8 87 6186 Phenol, 3-ethyl- 35.7 91 936

Naphthalene, 1 ,2,3,4-tetrahydro- 35.8 97 3348051 Naphthalene 36.6 95 512990 Phenol, 2,4,5-trimethyl- 36.8 94 3209 3,6-Dimethyl-1 H-indazole 37.3 72 1596 2-Methyl-1,2,3,4-tetrahydronaphthalene 37.4 94 1526 Benzene, cyclopentyl- 37.6 96 3809 5-Ethylindan 37.8 80 4680 Benzene, 1-pentenyl- 37.9 80 2964 1 H-lndene, 2,3-dihydro-4,7-dimethyl- 38.2 97 3072 1 H-lndene, 2,3-dihydro-4,6-dimethyl- 38.7 97 833 Naphthalene, 1 ,2,3,4-tetrahydro-5-methyl- 38.7 95 6063 Tridecane 39.1 96 1439

Naphthalene, 1 ,2,3,4-tetrahydro-6-methyl- 39.4 95 2914 Naphthalene, 2-methyl- 39.6 95 7990 Naphthalene, 1-methyl- 40.0 94 3767 1-Ethyl-1 ,2,3,4-Tetrahydronaphthalene 40.3 91 713 1-Naphthalenol, 1 ,2,3,4-tetrahydro- 41.0 87 550 Naphthalene, 6-ethyl-1 ,2,3,4-tetrahydro- 41.1 91 1104 1 (2H)-Naphthalenone, 3,4-dihydro- 41.6 96 4902 Naphthalene, 1 -ethyl- 42.1 97 1334 Naphthalene, 2-ethyl- 42.2 93 702 1 ,2,3,4-tetrahydro-6-isopropylnaphthalene 42.5 72 247 BHT 44.5 98 3519

Furan, 3-phenyl- 44.7 87 541

1 ,1'-Binaphthalene, 56.8 78 3593 Benz[a]anthracene-7,12-dione 57.9 90 8248 2,2'-Binaphthalene, 1 ,1',2,2',3,3',4,4'-octahydro- 58.6 93 2892 4,5,7,8,9, 10-Hexahydrobenzo[A]pyrene 58.9 93 1835 1 ,2'-Binaphthalene, 1',2',3',4'-tetrahydro- 59.3 90 1175 Benzo[a]pyrene, 4,5-dihydro- 59.7 86 865 4,5,6,7,8,9,9a,10,11 ,12-Decahydroperylene 60.6 91 1339