WO1994005618A1

WO1994005618A1 - Process for the production of diiodoketones

Info

Publication number: WO1994005618A1
Application number: PCT/US1993/007828
Authority: WO
Inventors: Jean Carroll Fleischer; Mark Rule
Original assignee: Eastman Kodak Company
Priority date: 1992-08-31
Filing date: 1993-08-20
Publication date: 1994-03-17

Abstract

This invention relates to a process for preparing a polynuclear aromatic diiodoketone compound comprising contacting: (A) a mono-iodo aromatic hydrocarbon containing 6 to 30 carbon atoms with (B) a non-iodo or mono-iodo aromatic hydrocarbon containing 6 to 30 carbon atoms, wherein either compound (A) or compound (B) is substituted with one or two substituents of formula (I), wherein X is halo, said contacting occurring in a solvent in the presence of a catalytic amount of an iron catalyst and under conditions of temperature and pressure such that the desired product is formed wherein the degree of mobility of iodine is less than 5 %. This invention also relates to certain diiododiketones which can be prepared by the process of the invention.

Description

PROCESS FOR THE PRODUCTION OF DIIODOKETONES

Field of the Invention

This invention relates to a process for preparing aromatic diiodoketones by Friedel—Crafts acylation methods and to certain diiododiketones.

Background of the Invention

In many prior art processes for preparing diiodoketones, the diiodoketones are reported to be prepared by Friedel—Crafts reactions using diacid chlorides and such catalysts as A1C1₃. For example, R.V. Tronov and E.S. Novikova (Polytech. Inst. , Tomεk) , Zhur. Obεhchei Khim. , 26, 1994—6 (1956) discloses the reaction of iodobenzene with p—iodobenzoyl chloride at 50°C in the presence of A1C1₃. However, the reported yields of 3,4'—diiodobenzophenone were low, ranging from 16.6 to 41%.

A problem with Friedel—Crafts acylation of iodine- containing aromatics is that iodine is much more easily removed from an aromatic ring than other halogens are. This property has been used to advantage; for instance, see United States Patent 4,806,698. However, this property presents a problem when it is necesεary to keep the iodine in place during Friedel—Crafts acylations. Under common acylation conditions, iodine tends to be quite mobile, even at ambient temperature.

In fact, a significant paradox is encountered in Friedel—Crafts acylations of iodo—substituted compounds. Iodine substituents deactivate aromatic hydrocarbons so that more strenous conditions increase the chances of mobilizing iodine.

None of the above prior art references recognize the problem of iodine mobility in Friedel—Crafts acylations. In German Patent 2,204,973, FeCl₃ is disclosed as a superior catalyst to A1C1₃ in Friedel— Crafts reactions in general, but the effect of FeCl₃ on the mobility of iodine is not disclosed.

It would be highly desirable to have a process for preparing diiodoketones that overcomes the problems of prior art processes, such as low yield.

Summary of the Invention

The process of the present invention overcomes disadvantages of the prior art. The process of the present invention can be described as a process for preparing a polynuclear aromatic diiodoketone compound comprising contacting:

(A) a mono-iodo aromatic hydrocarbon containing 6 to 30 carbon atoms with

(B) a non-iodo or mono-iodo aromatic hydrocarbon containing 6 to 30 carbon atoms, wherein either compound (A) or compound (B) is substituted with one or two subεtituents of

the formula — sC—X, wherein X is halo, said contacting occurring in a solvent in the presence of a catalytic amount of an iron catalyst and under conditions of temperature and pressure such that the desired product is formed wherein the degree of mobility of iodine is less than 5%.

The invention also relates to certain novel diiododiketones prepared by the above—described process.

Detailed Description of the Preferred Embodiments The diiodoketones produced according to this invention are useful as monomers for polyketosulfides (PKS) which exhibit outstanding stability properties. Iodine, when attached to an aromatic hydrocarbon, can be quite mobile under conditions required for Friedel— Crafts acylations. To make the desired diiodoketones, it is necessary to keep the iodine in place.

The needs in the art noted above are met with a process for preparing a polynuclear aromatic diiodoketone compound comprising contacting:

(A) a mono-iodo aromatic hydrocarbon containing 6 to 30 carbon atoms, preferably 6 to 20 carbon atoms, and more preferably, 6 to 14 carbon atoms, with

(B) a non-iodo or mono-iodo aromatic hydrocarbon containing 6 to 30 carbon atoms, preferably 6 to 20 carbon atoms, and more preferably, 6 to 14 carbon atoms.

Either compound (A) or compound (B) is substituted with one or two substituents of

the formula — 2C—X, wherein X is halo, such as chloro, bromo, fluoro or iodo.

The term "polynuclear" refers to polycyclic compounds or compounds having 2 or more rings.

The term "aromatic diiodoketone" refers to two similar or similar iodine—substituted moieties connected by a carbonyl functionality.

Examples of polynuclear aromatic diiodoketones which can be made in the process of the present invention include: 4,4'—diiodobenzophenone and 3,4'—diiodobenzophenone.

By the term mono—iodoaromatic hydrocarbon [compound (A) ] , we mean an aromatic hydrocarbon as described above substituted with one iodo group.

Preferred compounds having the structure of compound (A) above are as follows:

wherein Y is a direct bond, O, S, C, S, or S; X is

halo as described herein; and each Ar may be the same or different and is a aromatic moiety having one hydrogen atom removed for each substituent.

Examples of useful Ar moieties are phenylene, naphthylene, biphenylene, and the like. By "non-iodo aromatic hydrocarbon", [compound (B) ] , we mean an aromatic hydrocarbon which is not substituted with an iodo group as described hereinbelow.

The polynuclear aromatic compounds (compound (B) ) which may be used in the process of the invention may contain 10 to 30 carbon atoms and include all of those disclosed in British Patent 2,116,990 and U.S. Patent 4,611,033, incorporated herein by reference, plus other compounds having the general formulae H—R¹—X—R¹—H or H-R³-H, wherein each R¹, independently, and X are as defined hereinabove and R³ is a polynuclear hydrocarbon moiety. Examples of R³ moieties are those having 2, 3 or 4 fused rings, each of which is preferably aromatic, optionally substituted with up to 8 substituents such as with lower alkyl and/or lower alkoxy. Each of the fused rings of the R³ moiety may also optionally contain 1, 2 or 3 hetero atoms such as 0, N and/or P. Preferred are unsubstituted, non-heterocyclic R³ moieties wherein all rings are aromatic. Examples of non—iodoaromatic hydrocarbons which may be useful in the process of the invention include the following:

✓^"~'\ , S^{'~ '}\ __r_ ✓^*~"\

^'\ /^{'~u~ '}\ /^'~iJ~"\ /^'

N

/^* / \ / \

✓^* \ __ ✓^" X _ ✓^" \ ✓ ^"\

^"\ /^'~^^{~ '}\ /^'~^^{~ '}\ /^{' &υ}2 ^"\ ^'~^^~" /^'~^^{~ '}\ /^'

^• %_✓ \ _„_ x- X __ X

Other suitable non—iodoaromatic hydrocarbons which may be used include compounds such as diphenyl sulfide, fluorene, xanthene, dibenzofuran, thianthrene, phenoxathiin, dibenzo—p—dioxin, diphenylene, biphenyl, 4,4'—diphenoxybiphenyl, 2,2'—diphenoxybiphenyl, 1,2-di— phenoxybenzene, 1,4—diphenoxybenzene, 1,3—diphenoxy— benzene, 1—phenoxynaphthalene, 1,2—diphenoxynaphthalene, diphenyl ether, 1,5—diphenoxynaphthalene and the like. Preferred aromatic non—iodoaromatic hydrocarbons useful in the process of the invention are diphenyl ether, diphenyl sulfide, biphenyl, naphthalene, anthracene, phenanthrene, fluorene, xanthane, dibenzofuran, and dibenzo—p-dioxin.

Preferred compounds having the structure of compound (B) above have the following structure: H-R¹-G-R¹-H, or H-R²-H, wherein each R may be the same or different and is (a) a phenylene moiety optionally substituted with up to three substituents selected from the group consisting of lower alkyl and lower alkoxy,

(b) a naphthylene moiety optionally substituted with up to six substituents selected from the group consisting of lower alkyl and lower alkoxy, or

(c) a biphenylene moiety optionally substituted with up to eight substituents selected from the group consisting of lower alkyl and lower alkoxy; G is a direct bond, O, S, or —CH=CH—; and

R is a non—lodmated polynuclear aromatic compound.

Examples of phenylene moieties which are unsubstituted are: 1,2—phenylene, 1,3—phenylene, and 1,4—phenylene.

Examples of phenylene moieties which are substituted as described above are 2—methoxy—1,4— phenylene, 2—methyl—1,4—phenylene and 1—methyl-3,5— phenylene. Examples of lower alkyl are alkyl groups having 1 to 10 carbon atoms, such aε, methyl, ethyl, propyl, isopropyl, pentyl, hexyl, isononyl, nonyl, decyl. Preferred lower alkyl groups are methyl, ethyl, propyl, and isopropyl. Examples of lower alkoxy are alkoxy groups having 1 to 10 carbon atoms, such as methoxy, ethoxy, propoxy, pentoxy, heptoxy, isooxy, nonoxy. Preferred lower alkoxy groups are methoxy, ethoxy, propyloxy, and 1—methylethoxy. The optional substituents of the R¹ and R² groups may be the same or different.

Examples of napthylene moieties substituted aε described above are 1—methyl—2,6—naphthylene, 1—methyl— 2,7—naphthylene, and 4—methyl—1,8—naphthylene. Examples of unsubεtituted napthylene moieties are 1,8—naphthylene, 2,6—naphthylene, and 2,7—naphthylene. For the napthylene moieties, the description and the examples of lower alkyl and lower alkoxy substituents are as described above for the phenylene moietieε.

Examples of unsubεtituted biphenylene moieties are 4,4'—biphenylene, 3,4'—biphenylene, and 3,3'—biphenylene. Examples of substituted biphenylene moieties as described above are 1—methyl—4,4'—biphenylene and 4-methyl—3,4'—biphenylene.

For the biphenylene moieties, the description and the examples of lower alkyl and lower alkoxy subεtituents are as described above for the phenylene moieties.

The definition of G for the structure of compound (B) is the same as that described for Y aε deεcribed above for compound (A) . R₂ for compound (B) iε a non—iodinated polynuclear aromatic compound. The term "polynuclear" haε been previouεly described herein. By "non—iodinated" compound, we mean a compound which does not contain iodine. Examples of non—iodinated polynuclear aromatic compounds are phenylene, biphenylene, and naphthylene. It is preferred in the procesε of this invention that compound (B) have the following structure:

I-Ar-Y-Ar, I—Ar, or

• * \•/ •

I II I wherein Y and each Ar, independently, are as described hereinbefore for compound (A) . It is preferred in the process of this invention that compound (A) is selected from the group consisting of p—iodobenzoyl chloride, terephthaloyl chloride, isophthaloyl chloride, 2—iodo—6—naphthoyl chloride, 2,6—naphthaloyl chloride; and compound (B) is εelected from the group consisting of diphenyl ether, dibenzo¬ furan, diphenyl sulfide, biphenyl, naphthalene, anthracene, dibenzo—p—dioxin, fluorene, xanthane, and phenanthrene.

It is also preferred in the process of this invention that compound (A) is selected from the group consisting of p—iodobenzoyl chloride, terephthaloyl chloride, isophthaloyl chloride, 2,6—naphthaloyl chloride; and compound (B) is selected from the group consisting of p—iodobiphenyl, iodobenzene, and 4—iododiphenyl ether.

It iε preferred that compound (A) have the following structure:

I-Ar-Y-Ar , I—Ar, or

* \ s - s \ *

wherein Y is a direct bond, O, S I,, CC,, S, or S; and

each Ar may be the same or different and is a benzene ring having one hydrogen atom removed for each substituent; and that

compound (B) is of the structure

X-C-R³-G-R³-C-X, or

wherein R is

(a) a phenylene moiety optionally subεtituted with up to three εubεtituents selected from the group consisting of lower alkyl, lower alkoxy, both of which are described herein, halo, described herein, hydroxy, acyl such as acyl groups having 1 to 10 carbon atoms, preferably 1 to 4 carbon atoms, perfluoroalkyl having 1 to 10 carbon atoms, preferably having 1 to 4 carbon atoms, cyano, and dialkylamino wherein each dialkylamino group has 1 to 10 carbon atoms. Preferred dialkylamino groups wherein each alkyl moiety has 1 to 4 carbon atoms, and acylamino, preferred dialkyamino groups wherein each acylamino group has l to 4 carbon atoms;

(b) a naphthylene moiety optionally substituted with up to six substituents selected from the group consisting of lower alkyl, lower alkoxy, halo, hydroxy, acyl, perfluoroalkyl, cyano, nitro, dialkylamino, and acylamino, all of which have been described herein in (a) for compound (A) , or (c) a biphenylene moiety optionally substituted with up to eight substituentε selected from the group consisting of lower alkyl, lower alkoxy, halo, hydroxy, acyl, perfluoroalkyl, cyano, nitro, dialkylamino, and acylamino, all of which have been described herein in (a) for compound (A) ;

and wherein the —C—X moieties are directly bonded to an aromatic ring and are separated from each other by at least three carbon atoms; X is halo, as described herein;

and G is OO ,, SS ,, S , S ; ,, c C,, CCHH==CCH or C—R -O .

R^ is as described herein for compound (B) .

Any terms not defined for structure (A) are herein defined as the same as those for structure (B) hereinabove.

The contacting of a polynuclear aromatic diiodo— ketone compound with the hydrocarbons, as described for compounds (A) and (B) above, occurs in a solvent in the presence of a catalytic amount of an iron catalyst and under conditions of temperature and presεure such that the desired product is formed wherein the degree of mobility of iodine is leεs than 5%.

A catalytic amount of an iron catalyst is defined as a stoichiometric amount of an iron catalyεt. Exceεs catalyst may be used.

Although any iron catalyεt known in the art can be uεed, it is also preferred that the iron catalyst is elemental iron, more preferably in the form of powder or filings, or FeCl₃ (ferric chloride) .

The use of ferric chloride as the catalyst permits heating to a temperature sufficient to effect acylation. Also, the preferred range of mobility of the iodine is 0% to 5%, more preferably, 0% to 1%. Higher degrees of mobility substantially reduces yield of the desired isomer and εubεtantially increaεes the amount of free iodine formed in the reaction. The term "degree of mobility" means ability for iodine to be detached from the original carbon atom. Degree of mobility can be measured conveniently by formation of other isomers by NMR or by free iodine formed in the reaction medium or more conveniently by yield of reaction product.

The temperature can vary from 0° to 100°C. A preferred temperature range for the proceεε of the preεent invention is 0°—70°C.

The preferred presεure for the process of the invention is atmospheric presεure. However, any pressure may be used if it becomes necesεary to uεe a low boiling solvent above its boiling point. It iε alεo preferred that the molar ratio of compound (A): compound (B) is 1:0.5 to 1:4. It is more preferred that the molar ration of compound (A) : compound (B) is 1:0.5 to 1:2.

Any organic solvent normally used in the art for Friedel—Crafts reactions may be used in the proceεε of this invention. Reactions of iodobenzene may be run using an excess of iodobenzene as a solvent. Preferred solvents are 1,2—dichloroethane or o— ichlorobenzene.

Also, provided herein is a process for preparing a polynuclear aromatic diiododiketone comprising contacting:

(B) o N

in a solvent in the presence of a catalytic amount of an iron catalyst and under conditions of temperature and pressure to form a compound of the formula

Further, provided herein is a process for preparing a polynuclear aromatic diiodomonoketone comprising contacting:

5 (A) 1-_'^ O -C-Cl with 0 ••—• #--------•

(B) y o ^χ.-.^/ o ^x — i 5 in a solvent in the presence of a catalytic amount of an iron catalyst and under conditions of 0 temperature and pressure to form a compound of the formula

The meaning of "polynuclear aromatic diiodomono— 0 ketones has been previously given.

Even further, provided herein is a process for preparing a polynuclear aromatic diiododiketone comprising contacting:

in a εolvent in the preεence of a catalytic amount of an iron catalyεt and under conditions of 0 temperature and pressure to form a compound of the formula

Polynuclear aromatic diiododiketone is defined as a compound possessing three or more aromatic rings joined 0 by two carbonyl moieties.

The invention alεo provides a compound of the formula I-R ^I R^IJ ^I-I wherei .n each R 1 may be the same or di .fferent and is

(a) a phenylene moiety optionally substituted with up to three εubεtituents selected from the group consisting of lower alkyl and lower alkoxy,

(c) a biphenylene moiety optionally substituted with up to eight substituents selected from the group consisting of lower alkyl and lower alkoxy; 0, S, or -CH=CH-; and

R 2 is a non—iodinated polynuclear aromatic compound. The invention further provides a compound of the formula

wherein each R may be the same or different and is

(a) a phenylene moiety optionally substituted with up to three subεtituents selected from the group consisting of lower alkyl and lower alkoxy,

(c) a biphenylene moiety optionally substituted with up to eight substituents selected from the group consisting of lower alkyl and lower alkoxy; G is a direct bond, O, S, or —CH=CH-; and

R 2 i.s a non—i.odi•nated polynuclear aromatic compound.

For the purposes of defining the compounds of the invention, the terms "phenylene moiety", "lower alkyl", "lower alkoxy", "naphthalene moiety", "biphenylene moiety" and "non—iodinated polynuclear aromatic compound" have the same definition as described herein. For the above processes for preparing polynuclear aromatic diiodomonoketones and polynuclear aromatic diiododiketones, the solvent, catalytic amount of an iron catalyst, and conditions of temperature and presεure are the same as that described for the process for preparing polynuclear aromatic diiodoketones as described herein.

The invention can be further illustrated by the following examples of preferred embodiments thereof, although it will be understood that these examples are included merely for purposes of illustration and are not intended to limit the scope of the invention unless otherwise εpecifically indicated. The εtarted materials are commercially available unless otherwise noted. All percentages are by weight unless otherwise noted.

The following exampleε εhow that iodine is not lost when less active ferric chloride is used as the catalyst.

EXAMPLE 1

Anhydrous ferric chloride (36 g, 0.22 mole) is added portionwise to a stirring mixture of iodobenzene (122.4 g, 0.6 mole) and p-iodobenzoyl chloride (53.2 g, 0.2 mole) in 1,2—dichloroethane (200 ml) while gradually heating the mixture to 70°C. After stirring under nitrogen at 70-75° for 24 hours, the reaction mixture is treated with cold water then with heptane to isolate the 4,4'—diiodobenzophenone which is essentially free from monoiodobenzophenone (mol. wt. 308) . High purity 4,4'—diiodobenzophenone is obtained in 50—60% yield by recrystallization from toluene.

EXAMPLE 2

Anhydrous ferric chloride (18 g, 0.11 mole) is added portionwise at room temperature under a nitrogen atmoεphere to a εtirring mixture of p—iodobiphenyl (28 g, 0.1 mole) and terephthaloyl chloride (10.1 g, 0.05 mole) in o—dichlorobenzene. After reaction for 3 hours, Field Desorption Mass Spectrometry shows the major product to be 1,4—bis(4—iodobenzoyl)benzene (mol. wt. 690) with no indication of iodine loss.

EXAMPLE 3 p—Iodobiphenyl (11.2 g, 0.04 mole) and p-iodobenzoyl chloride (10.6 g, 0.04 mole) are reacted at ambient temperature in o—dichlorobenzene (90 ml) in the presence of anhydrous ferric chloride (7.3 g, 0.045 mole). The major product after 3 hours of reaction as determined by Field Desorption Mass Spectrometry is 4—iodo—4'—(4—iodophenyl)benzophenone, molecular weight 510.

The following examples demonstrate that the use of aluminum chloride catalyst in the preparation of iodo— ketones by Friedel—Crafts acylations results in unacceptable mixtures of products due to iodine loss.

EXAMPLE 4

Powdered aluminum chloride (29 g, 0.22 mole) iε added portionwise under an atmosphere of nitrogen to a stirring mixture of p-iodobenzoyl chloride (53.3 g, 0.2 mole) and iodobenzene (122.4 g, 0.6 mole) and the mixture is carefully heated to 50°C. After reacting at 50°C for 15 hours, crude reaction product is isolated from methanol. Field Desorption Mass Spectrometry indicates a major component in this material at molecular weight 308 which corresponds to mono¬ iodobenzophenone. Recrystallization from toluene results in a 27% yield of 4,4'—diiodobenzophenone that remains contaminated with the monoiodo compound. EXAMPLE 5

Powdered aluminum chloride (11.5 g, 0.8 mole) is added portionwise under an inert atmosphere to a stirring mixture of p—iodobiphenyl (22.4 g, 0.8 mole) and terephthaloyl chloride (7.6 g, 0.0375 mole) in o—dichlorobenzene and the mixture iε gradually heated. After 3.5 hours at 50—75°C, Field Desorption Mass Spectrometry indicates a mixture of reaction products including 1,4—bis(4—iodobenzoyl)benzene (mol. wt. 690), the monoiodoketone (mol. wt. 565) and the unεubεtituted ketone (mol. wt. 439) . Theεe three compoundε are alεo the major product components when this reaction is carried out at room temperature.

The invention has been described in detail with particular reference to preferred embodimentε thereof, but it will be underεtood that variations and modifi¬ cations can be effected within the spirit and scope of the invention. Moreover, all patents, patent applica— tions (published or unpublished, foreign or domestic) , literature references or other publications noted above are incorporated herein by reference for any disclosure pertinent to the practice of this invention.

Claims

We Claim:

1. A process for preparing a polynuclear aromatic diiodoketone compound comprising contacting:

(A) a mono-iodo aromatic hydrocarbon containing 6 to 30 carbon atoms with

(B) a non-iodo or mono-iodo aromatic hydrocarbon containing 6 to 30 carbon atoms, wherein either compound (A) or compound (B) iε εubstituted with one or two subεtituents of

the formula —9C—X, wherein X is halo, εaid contacting occurring in a εolvent in the presence of a catalytic amount of an iron catalyst and under conditions of temperature and preεεure εuch that the desired product is formed wherein the degree of mobility of iodine is less than 5%.

2. The process of Claim 1 wherein compound (A) is of the following structure:

I-Ar-Y-Ar-C-X,

I-Ar-C-X, or

• * \•/ •

I II I

_ — *

wherein Y is a direct bond, 0 , S , C , s , or S; X is

halo; and each Ar may be the same or different and is a benzene ring having one hydrogen atom removed for each substituent. 3. The process of Claim 2 wherein compound (B) is of the structure

H-R¹-G-R¹-H, or

H-R²-H, wherein each R may be the same or different and is

(a) a phenylene moiety optionally substituted with up to three subεtituents εelected from the group conεisting of lower alkyl and lower alkoxy,

(b) a naphthylene moiety optionally subεtituted with up to εix εubεtituentε selected from the group consiεting of lower alkyl and lower alkoxy, or

(c) a biphenylene moiety optionally εubεtituted with up to eight εubεtituents selected from the group consisting of lower alkyl and lower alkoxy; G is a direct bond, O, S, or —CH=CH—; and R R² 2 ilsε aa non—iodinated polynuclear aromatic compound

. The process of Claim 3 wherein compound (A) is selected from the group consisting of p—iodobenzoyl chloride, terephthaloyl chloride, isophthaloyl chloride, 2—iodo—6—naphthoyl chloride, 2,6—naphthaloyl chloride; and compound (B) is selected from the group consisting of diphenyl ether, dibenzofuran, diphenyl sulfide, biphenyl, naphthalene, anthracene, dibenzo—p—dioxin, fluorene, xanthane, and phenanthrene.

5. The process of Claim 2 wherein compound (B) is of the structure

I-Ar-Y-Ar, I—Ar, or

wherein Y and each Ar, independently, are aε described hereinbefore.

6. The process of Claim 5 wherein compound (A) iε εelected from the group consisting of p-iodobenzoyl chloride, terephthaloyl chloride, isophthaloyl chloride, 2,6—naphthaloyl chloride; and compound (B) is selected from the group consiεting of p—iodobiphenyl, iodobenzene, and 4—iododiphenyl ether.

7. The proceεs of Claim 1 wherein compound (A) is of the structure: I-Ar-Y-Ar,

I—Ar, or

wherein Y is a direct bond ., 00,, SS,, IC, IS, oorr IS,; and

each Ar may be the same or different and is a benzene ring having one hydrogen atom removed for each subεtituent; and

compound (B) is of the structure χ_?__R ³ _÷R ³_?-χ, or

wherein R 3 i.s (a) a phenylene moiety optionally subεtituted with up to three substituents selected from the group conεiεting of lower alkyl, lower alkoxy, halo, hydroxy, acyl, perfluoroalkyl, cyano, nitro, dialkylamino, and acylamino,

(b) a naphthylene moiety optionally εubεtituted with up to εix εubεtituentε selected from the group consisting of lower alkyl, lower alkoxy, halo, hydroxy, acyl, perfluoroalkyl, cyano, nitro, dialkylamino, and acylamino, or

(c) a biphenylene moiety optionally subεtituted with up to eight substituentε εelected from the group conεisting of lower alkyl, lower alkoxy, halo, hydroxy, acyl, perfluoroalkyl, cyano, nitro, dialkylamino, and acylamino;

and wherein the -—2C-—>X moieties are directly bonded to an aromatic ring and are separated from each other by at least three carbon atoms; X is halo;

and G is O, S, i, C, CH=< CH or C— -O

8. The process of Claim 1 wherein said iron catalyst is elemental iron or FeCl₃.

9. The process of Claim 1 wherein said solvent is 1,2—dichloroethane or o—dichlorobenzene.

10. The process of Claim 1 wherein said temperature is 0°C to 100°C and said presεure is atmospheric.

11. The process of Claim 2 wherein the molar ratio of compound (A):compound (B) is 1:0.5 to 1:4. 12. A process for preparing a polynuclear aromatic diiododiketone comprising contacting:

(A) I _-.^^/*oO^'\^---?C--cCl with

(B) y o ^N. o in a solvent in the presence of a catalytic amount of an iron catalyst and under conditions of temperature and pressure to form a compound of the formula

13. A process for preparing a polynuclear aromatic diiodomonoketone comprising contacting:

in a εolvent in the preεence of a catalytic amount of an iron catalyst and under conditions of temperature and pressure to form a compound of the formula

•—• •—• • ~-~"•

I_. o .—C—• o •—• O •—I

14. A process for preparing a polynuclear aromatic diiododiketone compriεing contacting:

•—• (A) .^ O -l with

- Ir—.

15. A compound of the formula _X-_R ^I _R ^I^-_R ^I-_X wherein each R may be the same or different and iε

(a) a phenylene moiety optionally εubεtituted with up to three εubεtituentε εelected from the group conεiεting of lower alkyl and lower alkoxy, (b) a naphthylene moiety optionally εubstituted with up to six substituents selected from the group conεiεting of lower alkyl and lower alkoxy, or (c) a biphenylene moiety optionally εubεtituted with up to eight substituents selected from the group consisting of lower alkyl and lower alkoxy; O, S, or —CH=CH—; and

R 2 is a non—i•odinated polynuclear aromatic compound.

16. A compound of the formula

!__R ^ι_i ^ι_<^_R ^ι_i wherein each R may be the same or different and is (a) a phenylene moiety optionally subεtituted with up to three εubstituents selected from the group consisting of lower alkyl and lower alkoxy,

(b) a naphthylene moiety optionally substituted with up to six substituentε selected from the group consisting of lower alkyl and lower alkoxy, or

(c) a biphenylene moiety optionally subεtituted with up to eight εubεtituentε selected from the group consiεting of lower alkyl and lower alkoxy;

G iε a direct bond, O, S, or —CH=CH—; and

2 ιε a non—i.odinated polynuclear aromatic compound.