CA1124742A - Aromatic salicylate process - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

An aromatic salicylate process comprising contacting a phenol, carbon monoxide, a base, a Group VIIIB element selected from ruthenium, rhodium, palladium, osmium, iridium or platinum and recovering at least a portion of an aromatic salicylate. The resulting aromatic salicylates are useful in plastics and lacquers as well as in pharmaceuticals.

Description

~ 7~ ~ RD-9367 This invention relates to an aromatic salicylate process comprising contacting a phenol, carbon monoxide, a base, a Group VIIIB element selected from ruthenium, rhodium, palladium, osmium, iridium or platinum and recovering at least a portion of an aromatic salicylate.
In Canadian patent applications of A.J. Chalk Serial No. 288,493 filed October 6, 1977 and Serial No. 300,634 filed April 6, 1978, both commonly assigned herewith, it is broadly disclosed that aromatic carbonates can be prepared by contacting a phenol, carbon monoxide, a base, and a Group VIIIB element selected from ruthenium, rhodium, palladium, osmium, iridium or platinum having an oxidation state greater than zero.
Although A.J. Chalk recognized that aromatic carbonates could be formed, Chalk did not recognize that, under some process parameters encompassed by Chalk's aromatic carbonate process,.not only were aromatic carbonates formed but concurrently aromati:c salicylates were also formed.
This.invention embodies an aromatic salicylate process 20 compris.ing~contacting a phenol, carbon monoxide, a base, and a Group VII.IB.:eIement seIected from ruthenium, rhodium, palladium, osmium, iridium or platinum and recovering at least a portion of an aromatic salicylate.
The reactants and the resulting .reaction products of my process: can be illustrated by the:following general equations which.are furnished for illustrative purposes only, . since the reaction mechanisms-involved in the preparation of aromatic salicylates (Eq. 1) may be much more complex.
PdCl2 + 2R~OH + 2R3N~+ CO

O.
~ Pd + HO-R"-C-Q-R`: +:2R3~HCl wherein R is an alkyl radical (incluaing cycloalkyl), R' is an aryl radical, and R" is an arylene radical.

~ P~ - 1 - ~

In general any nuclearly hydroxy substituted aromatic compound can be used in my process subject to the proviso that there be at least one ortho positioned hydrogen atom relative to the hydroxy substituent, such compounds being defined herein and in the appended claims as "a phenol". Illustratively the phenol (or phenolic reactants) can be descrihed by the formula:
I. a ( OH)X

wherein R represents an aromatic radical, where the -OH
radical is attached directly to an aromatic ring carbon atom and x is a number being at least equal to 1, advantageously from 1 to 4, and preferably from 1 to 2.
The R radical can be carbo-or hetero-monocyclic, polycyclic or fused polycyclic, and can have two or more cyclic systems (monocyclic, polycyclic or fused polycyclic systems) which are connected to each other or by bi- or multivalent radicals.
Preferred phenolic reactants are phenols containing from 6 to 30, and more preferably from 6 to 15 carbon atoms.
Illustrative of commercially important phenolic reactants included within the above description are the following:
phenol itself (hydroxy benzene); napthol; ortho-, meta-, or paracresol; catechol; meta, para-xylenol; resorcinol;
the various isomers of dihydroxydiphenyl; the isomers of dihydroxynapthalene; bis(4-hydroxyphenyl) propane-2, 2;
a, a' -bis(4-hydroxyphenyl)-p-diiso-propylbenzene; 4,4'-dihydroxy-3; 5,3'-trichlorophenylpropane-2,2; 4,4'-dihydroxy-3,5,3' -tribromophenylpropane-2,2; phloroglucinol, dihydroxy oligomers, for example an oligomer derived from bisphenol-A, etc.
A generally preferred bisphenol that can be used in my process can be described by the following formula:

11;24~7~ 2 RD- 9 3 6 7 \~. Rl ~
I. HO ~, C ~ OH, R /4 R ~ 4 where Rl and R2 are hydrogen, Cl 4 alkyl or phenyl, and at least one of R3 or R4 is hydrogen. Another preferred bisphenol comprises formula I where R and R are as defined before and at least one of R3 iS hydrogen and the other is hydrogen or Cl 4 alkyl, and at least one of R is hydrogen and the other is hydrogen or Cl 4 alkyl. Especially preferred is bis(4-hydroxyphenyl)propane-2, 2, also commonly known as "bisphenol'A" (BPA).
Any Group VIIIB element, defined herein and in the appended claims as "the Group VIIIB element", can be employed subject to the proviso that it is selected from ruthenium, rhodium, palladium, osmium, iridium or platinum.
The Group VIIIB elements can be employed in any of their well-known oxidation states as well as their zero valent elemental, i.e. metallic, form.
~ Illustratively, the Group VIIIB elements can be - present in ionic, inorganic or organic compound or complex, etc. forms. The Group VIIIB elements can be employed in oxide, halide, nitrate, sulfate, oxalate, acetate, carbonate, propionate, hydroxide, tartrate, etc., forms.
The Group VIIIB elements can be employed in complex form, e.g. with ligands, such as carbon monoxide, nitriles, tertiary amines, phosphines, arsines, or stibines, etc., and illustratively are often represented by those skilled in the art as mono-, di-, or poly- nuclear Group VIIIB element forms. Generally, the dimeric or polymeric forms are considered to contain Group 11~24 ~ RD-9367 VIIIB atoms bridged by ligands, halogens, etc. Pref-erably the Group VIIIB elements form homogeneous mixtures when combined with the phenolic reactants, especially when the process is carried out under liquid phase reaction conditions.
Illustrative of the generally preferred Group VIIIB element compounds or complexes that can be used in my process follow: RuC12, RuBr2, RuI2, Ru(CO)2CI2, Ru(CO2I2, Ru(CO)4C12, Ru(CO)4Br2, Ru(CO)4I2,RuC13, RuBr3, RuI3, etc-,

2' r2, PdI2, ~Pd(CO)C12]2~ [Pd(CO)Br2~2~ LPd(CO)I

(C6H5CN)2PdC12, PdC14, Pd(OH)2(CNC4Hg)2, PdI2(CNC6H5)2, Pd(OH)2(CNCH3OC6H5)2, Pd(CNC4Hg)4, etc.; Rh(CO)C12, Rh(CO)Br2, Rh(CO)I2, RH2C12(CO)2, Rh2( )4 2 2 4 2 Rh2(CO)4I2, Rh(CO)2C1 2' RhC13, RhBr3, RhI3, etc.;
OS(CO)3C12, OS(CO)3Br2~ Os(CO)3I2~ OS(CO)4C12, OS~CO)4Br2~
OS(co)4I2~ S(c)8cl2' S(c)8Br2~ OS(CO)8I2, OsC12, OsC13, OsI2, OsI3, OSBr3, OsBr4 and OsC14, etc.; IrC13, IrC13(CO), Ir2(CO)8, IrC13, IrBr3, IrC13, IrBr4, IrI4, etc.; PtC12, PtBr2, PtI2, Pt(CO)2C12, Pt(CO)2Br2, Pt(CO)2I2, Pt(CO)2 -C14, Pt(CO)2Br4, Pt(CO)2I4, Pt(CO)3C14, Pt(CO)3Br4, Pt(CO)3I4r PtC12(CNC6H5)2' Illustrative of ligands that can be associated with the Group VIIIB elements in complex form -- other than and, optionally, in addition to carbon monoxide -- include organic tertiary amines, phosphines, arsines and stibine ligands of the following formula:

( )3Q

wherein, independently, each E is selected from the radicals Z and OZ, where independently each Z is selected from organic radicals containing from 1 to 20 carbon atoms, and wherein independently each Q is selected from nitrogen, il~ 742 RD-9367 phosphorus, arsenic or antimony. Preferably, the organic radicals are free of active hydrogen atoms, reactive unsaturation, and are oxidatively stable. More preferably, the E groups are alkyl, cycloalkyl and aryl radicals and mixtures thereof, such as alkaryl, aralkyl, alkcycloalkyl containing from 1 to 10 carbon atoms, and even more preferably each E is an aryl group containing from 6 to 10 carbon atoms.
Illustrative of the generally known presently preferred Group VIIIB complexes which contain ligands include the following: RUcl2[p(c6H5)3]4~[Rh(co)2 ]2~
2 5 2 2' [P(c4H9)3l2pdcl4~ [(C6H5)3P]3IrCl (CO) [(C6H5)3As]3IrC13(CO)~ [(c6H5)3sb]3Ircl3(co)~ [(C6H5)3P]2PtF
(C H5)3P]2PtF2(co)2~ Pt[(C6H5)3 ]2 2 The Group VIIIB element compounds and/or complexes can be prepared by any method well-known to those skilled in the art including the methods referenced in the following publications:
- Treatise on Inorganic Chemistry, Volume II, H.Remy, 2Q Elsevier Publishing Co. (1956);
; Reactions of Transition-Metal Complexes, J.P.
Candlin, K.A. Taylor and D.T. Thompson, Elsevier Publishing Co. (1968) Library of Congress Catalog Card No. 67-19855;
~; Organic Syntheses Via Metal Carbonyls, Vol.l, I. Wender and P. Pino, Interscience Publishers (1968) Library of Congress Catalog Card No. 67-13965;
The Organic Chemistry of Palladium, Vols. I and II, 3n P.M. Maitlis, Academic Press (1971) Library of Congress Catalog Card No. 77-162937;
The Chemistry of Platinum and Palladium, F.R.

~1~47'1;~ RD--93 67 Hartley, Halsted Press (1973);
The process can be carried out in the absence of any solvent, e.g. where the phenolic reactant acts as both a reactant and a solvent/ however preferably is carried out in the presence of a solvent, and more preferably solvents of the general class: methylene chloride, ethylene dichloride, chloroform carbon tetrachloride, tetrachloroethylene, nitromethane, hexane, 3-methylpentane, heptane, cyclohexane, methylcyclohexane, cyclohexane, isooctane, p-cymene, cumene, decalin, toluene, benzene, diphenylether, dioxane, thiophene, dimethyl sulfide, ethyl acetate, tetrahydrofuran, chlorobenzene, anisol, bromobenzene o-dichlorobenzene, methyl formate, iodobenzene, acetone, acetophenone, etc., and mixtures thereof.
In general, the process can be carried out in any basic reaction medium, preferably, that provided by the presence of any inorganic or organic base or mixtures thereof.
Representative of basic species which can be employed are the following: elemental alkali and alkaline earth metals;
basic quaternary ammonium, quaternary phosphonium or tertiary sulfonium compounds; alkali or alkaline earth metal hydroxides; salts of strong bases and weak acids; prlmary, secondary or tertiary amines; etc. Specific examples of the aforementioned are sodium, potassium, magnesium metals, etc.;
quaternary ammonium hydroxide, tetraethyl phosphonium hydroxide, etc.;sodium, potassium, lithium, and calcium hydroxide; quaternary phosphoniumr tertiary sulfonium, sodium, lithium and barium carbonate, sodium acetate, sodium benzoate, sodium methylate, sodium thiosulfate, sodium sulfide, sodium tetrasulfide, sodium cyanide, sodium hydride, sodium borohydride, potassium fluoride, triethylamine, trimethylamine, allyldiethylamine, benzyldimethylamine, ~L~74~ RD-9367 dioctylbenylamine, dimethylphenethylamine, l-dimethyl-amino-2-phenylpropane, N,N,N', N'-tetramethylenediamine, 2,2,6,6-tetramethylpyridine, N-methyl piperidine, pyridine, 2,2,6,6-N-pentamethylpiperidine, etc. Especially preferred bases are sterically hindered amines, e.g. diisopropylmono-ethylamine, 2,2,6,6,N-pentamethylpiperidine, etc.
The process of my invention may be carried out under catalytic reaction conditions employing an oxidant including oxygen, a redox agent and a drying agent at reaction temperatures in excess of 100 C., more preferably 150 C. and even more preferred 200 C., since optimum yields of aromatic salicylate are obtained under these reaction conditions. Suitable oxidants are compounds or complexes of a periodic Group IIIA, IVA, VA, VIA, IB, IIB, VIB, VIIB
or VIIIB, element where the oxidant has an oxidation potential greater than or more positive than the Group VIIIB
element. Typical oxidants for the Group VIIIB elements are compounds of copper, iron, manganese, cobalt, mercury, lead, cerium, uranium, bismuth, chromium, etc. Of these, copper salts are preferred. The anion of the salt may be a Cl 20 carboxylate, halide, nitrate, sulfate, etc., and preferably is a halide., eg., chloride, bromide, iodide, or fluoride.
Illustrative of typical oxidant compounds are cupric chloride, cupric bromide, cupric nitrate, cupric sulfate, cupric acetate, etc. In addition to the compounds described above, gaseous oxygen may be employed as the sole oxidant in the herein claimed process. Typically, compounds or complexes of a periodic Group IIIA, IVA, VA, IB, IIB, VB, VIB, VIIB, and VIIIB element are preferably employed, in conjunction with oxygen, as redox co-catalysts in order to enhance the rate of oxidation of the Group VIIIB metal by gaseous oxygen.
As used herein and in the appended claims, the ~ 7~2 RD-9367 expression "complexes" includes coordination or complex compounds well known to those skilled in the art such as those described in Mechanisms of Inorganic Reactions, Fred Basolo and Ralph G. Pearson, 2nd Edition, John Wiley and Sons, Inc. (1968). These compounds are generally defined herein as containing a central ion or atom, i.e. a periodic Group IIA, IVA, VA, VIA, IB, IIB, VIB, VIIB or VIIIB element and a cluster of atoms or molecules surrounding the periodic group element. The complexes may be nonionic, or a cation or anion, ; 10 depending on the charges carried by the central atom and the coordinated groups. The coordinated groups are defined herein as ligands, and the total number of attachments to the central atom is defined herein as the coordination number. Other common names for these complexes include complex ions (if electrically charged), Werner complexes, coordination complexes or, simply, complexes.
The redox components as a class comprise any compound or complex of a periodic Group IIIA, IVA, VA, IB, IIB, VB, VIB, VIIB and VIIB, which catalyze the oxidation of the Group VIIIB elements, i.e. ruthenium, rhodium, palladium, osmium, iridium or platinum in the presence of oxygen, from a lower oxidation state to a higher oxidation state.
Particularly suited redox agents appear to be manganese or cobalt chelates. Illustrative of manganese complexes which are preferred are those having the general formula LMn, wherein L is a ligand derived from an omega-hydroxyoxime or an orthohydroxyareneoxime.Illustratively, the manganese may be employed in any of its oxidation states e.g. for -1 to +7. The use of these compounds is further described and claimed in my Canadian patent application Serial No. 300,608 filed April 6, 1978 and commonly assigned ~4 7A2 RD-9367 herewith. Also described in that application are suitable drying agents which may be used in the instant process.
These include molecular seives, alumina, barium oxide, calcium chloride, calcium oxide, calcium sulfate, lithium chloride, and other compositions generally known to those skilled in the art.
As a source of oxygen there may be employed for example gaseous oxygen or liquid oxygen. Preferably either air or gaseous oxygen are employed.
Generally any reasonable amount of oxygen can be employed. Preferably the process is carried out under positive oxygen pressure, i.e., where oxygen is present in Stoichiometric amounts sufficient to form the desired aromatic mono- or polycarbonate. In general, oxygen pressures within the range of from about 0.1 to 500 atmospheres, or even higher, can be employed with good results. Presently j preferred are oxygen pressures within the range of from about 1/2 of 200 atmospheres.
Any reasonable amount of the oxidant can be employed. For example, oxidant to phenol mole proportions within the range of from about 0.001:1 or lower to about 1000:1 or higher are effective; however, preferably ratios from 0.1:1 to 10:1 are employed to insure an optiumum conversion of phenol to aromatic carbonate. It is essential wherein an oxidant is employed -- in the substantial absence of oxygen, i.e. not as a redox co-catalyst component --that the oxidant be present in amounts stoichiometric to carbonate moieties; i.e., -O-C-O-, formed in the preparation of the aromatic carbonates.
Any reasonable amount of redox co-catalyst conponent can be employed. For example, redox catalyst to phenol mole proportions within the range of from about 0.0001:1 or lower 1124~2 RD-9367 to about 1000.1 or higher are effective; however, preferably ratios of from .0001:1 to 1:1, and more preferably 0.001:1 to 0.01:1 are employed.
Any reasonable amount of base can be employed.
In general, effective mole ratios of base to the Group VIIIB
elements are within the range of from about 0.00001:1 to about 100:1 or higher, preferably from 0.5:1 to about 10:1, and more preferably from 1:1 to 2:1. Generally, mole ratios of at least 1:1 enhance both the reaction rate and the yield of aromatic carbonate.
Any reasonable amount of the Group VIIIB element can be employed. For example, Group VIIIB element to phenol mole proportions within the range of from about 0.0001:1 or lower to about 1000:1 or higher are effective; however, preferably ratios of from 0.001 to 0.01 are employed in my catalytic reation.
Any reasonable amount of carbon monoxide can be employed. Preferably the process is carried out under positive carbon monoxide pressure; i.e., where carbon monoxide is present in stoichiometric amounts sufficient to form the desired aromatic mono- or polycarbonate. In general, carbon monoxide pressures within the range of from about 1/2 to 500 atmospheres, or even higher, can be employed with good results. Presently preferred are CO pressures within the range of from 1 to 200 atmospheres.
Any reasonable amount of solvent, preferably inert, can be employed. In general, optimum solvent to phenolic reactant mole proportions are from 0.5:99.5 to 99.5:0.5, preferably from 50:50 to 99:1.
3Q Any reasonable reaction temperature can be employed. In general, optimum reaction temperatures are 0C, or even lower, to 300C, or even higher and more often 0C to 50C.

112~ ~42 RD 9367 Any reasonable reaction time period can be employed. Generally optimum reaction time periods are about 0.1 hour or even less to about 10 hours or even more.
Following some of the procedures described herein, aromatic salicylates can be formed. These aromatic salicylates, i.e. aromatic compounds which can be defined as "salicylate" can be generically described by the following formula:
O
HO-R -C-O-R

wherein Rb represents an aromatic radical wherein the hydroxyl radical is positioned ortho relative to the carboxylate, i.e.
O
-C-O- radical, and Rc represents an aromatic radical. The Rb and Rc radicals can be carbo- or hetero-monocyclic, poly-cyclic, or fused polycyclic, and can have two or more cyclic systems (monocyclic, polycyclic or fused polycyclic systems) which are directly joined to each other by single or double valence bonds, or by bi- or multivalent radicals.
To optimize the yield of aromatic salicylate a preferred process parameter of my invention comprises delaying the addition of carbon monoxide until the phenolic reactant, Group VIIIB elements and base, have formed a salicylate preliminary reaction admixture, i.e. "salicylate PRM" .
In order to optimize the yield of aromatic salicylate, a more preferred process parameter comprises contacting a phenolic reactant with a Group VIIIB element having an oxidation state of at least +2 with a base prior to contacting a previously formed resulting "salicylate PRM" with carbon monoxide. In addition, preferably my ~i24742 RD-9367 process is carried out under reaction conditions which exclude from the reaction media halides, i.e. chloride, bromide, iodide or fluoride, in amounts which are in excess of the amount theoretically required to form a Group VIIIB metal halide salt.
My preference of delaying the introduction or addition of halides and/or carbon monoxide to a "salicylate PRM" until formation of the "salicylate PRM" is a result of my finding that the order of addition and type of reactants employed in my process significantly affects the formation of aromatic salicylates. The significance of the order of addition is further exemplified when this disclosure is read in conjunction with the disclosure of my United States Patent 4,096,168 issued June 20, 1978.
In order that those skilled in the art may better understand my invention, the following examples are given which are illustrative of the best mode of this invention.
However, these examples are not intended to limit the invention in any manner whatsoever. In the examples, unless otherwise specified, all parts are by weight and the reaction products were verified by infrared spectrum, C-13 nuclear magnetic resonance and mass spectrometry.
EXAMPLE I
Preparation of phenyl salicylate using hydroxybenzene carbon monoxide, diisopropylmonoethylamine and bis (benzonitrile)- palladium (II) dichloride.
A reaction vesseI was charged with 1.50 g.
(4.0 mml.) of bis (benzonitrile) palladium (II) dichloride, Q.77 g. (8.0 mmol.~ of phenol, and 10 ml. of methylene chIoride. The mixture was stirred, flushed slowly with carbon monoxide, and 1.5 g. (11.6 mmol.) of diisopropyl-monoethylamine ~as added. The solution immediately turned black and palladium metal precipitated. After stirring at 11~742 RD 9367 room temperature for three hours, the mixture was filtered.
The precipitate was washed with methylene chloride, then dried in a stream of air, to yield 0.43 g. (101%) of palladium metal. The filtrate was analyzed and the presence of 0.23 g. (52% yield) of diphenyl carbonate and 0.45 g.
153%) of phenyl salicylate of the formulas, respectively, was formed:

OH
~ O-C-O ~ and ~ ~ C O

EXAMPLE II
Preparation of 4'-methylphenyl-2-hydroxy-5-methyl benzoate using 4-methylphenol as the phenolic reactant.
A reaction vessel was charged with 0.77 g.
(2.0 mmol.) of bis(benzonitrile) palladium (II) dichloride, 7 ml. of methylene chloride, and a solution of 0.22 g.
(2.0 mmol.) of 4-methyl-phenol plus 0.52 g. (4.0 mmol.) of diisopropylmonoethylamine dissolved in 5 ml. of methylene chloride. Carbon monoxide was bubbled through the solution for two hours. The analysis of the products was 0.15 g.
(60%) of 4, 4'-dimethyldiphenyl carbonate and 0.18 g. (38%) of 4'-methylphenyl-2-hydroxy-5-methyl benzoate af the formulas, respectively:

OH

33C ~ -C-O ~ C33 ~ C-O ~ C33 1~4~4~ RD-9367 EXAMPLE III
Preparation of 4(a~a-dimethylbenzyl)phenyl 5-(a~-dimethylbenzyl)-2hydroxybenzoate using p-cumyl phenol as the phenolic reactant.
A reaction vessel was charged with 0.77 g.
(2.0 mmol.) of bis(benzonitrile)palladium(II) dichloride, 7 ml. of methylene chloride, and a solution of 0.42 g.
(2.0 mmol.) of p-cumylphenol plus 0.52 g~ (4.0 mmol.) of diisopropylmonoethylamine dissolved in 7 ml. of methylene chloride. The mixture was stirred to effect solution and carbon monoxide bubbled through the solution overnight.
Subsequent work-up showed the presence of 0.32 g.
(71% yield) of 4, 4~-(a~-dimethylbenzyl) diphenyl carbonate and 0.18 g. (20%) of 4-(a,~-dimethylbenzyl) phenyl 5-(~,a-dimethylbenzyl)-2-hydroxybenzoate of the formulas, respectively:

~3 ~ ~ , ~ and OH
~~ C O~~C--~
~ CH3 CH -C-cH

3 1 3 [~

EXAMPLE IV
Preparation of 4'-methylphenyl-2-hydroxy-5-methyl benzoate under pressure.
The reaction medium contained 4.03 g. (1.05 mmol.) of bis(benzonitrile~palladium(II) dichloride, 20 ml. of ~ 7~ 2 RD 9367 methylene chloride, 0.108 g. of 4-methylphenol, 1.131 g.
of diisopropylmonoethylamine, and sufficient carbon monoxide to charge the vessel to 65 psi. The product yield was 38%
of 4,4'-dimethyldiphenyl carbonate and 41% of 4'-methyl-phenyl-2-hydroxy-5-methyl benzoate.
EXAMPLE V
Preparation of 4'-methylphenyl-2-hydroxy-5-methyl benzoate using palladium (II) dichloride.
A reaction vessel was charged with 10 ml. of methylene chloride, 0.108 g. (1.0 mmol.) of 4-methylphenol, 0.137 g. (1.1 mmol.) of diisopropylmonoethylamine, and sufficient carbon monoxide to pressure the vessel to 65 psi.
O.lg9 g. (1.12 mmol.) of palladium (II) dichloride, i.e.
PdC12, was added. The product yield was 0.98 g. (81% of

4,4'-dimethyldiphenyl carbonate and 0.08 g. (7%) of 4'-methylphenyl-2-hydroxy-5-methyl benzoate.
EXAMPLE VI
Preparation of 4'-methylphenyl-2-hydroxy-5-methyl benzoate using 4-methyl sodium phenoxide as the base.
The reaction vessel contained 0.184 g. (1.04 mmol.) of palladium (II) dichloride, 10 ml. of methylene chloride, 0.125 g. (1.16 mmol.) of 4-methylphenol, 0.080 g.
(0.62 mmol.) of 4-methyl sodium phenoxide and sufficient carbon monoxide to charge the vessel to 63 psi. The product yield was 5% of 4,4'-dimethyldiphenyl carbonate and 8% of 4'-methylphenyl-2-hydroxy-5-methyl benzoate.
EXAMPLE VII
Preparation of 4'-methylphenyl-2-hydroxy-5-methyl benzoate using potassium carbonate as a base.
The reaction vessel contained 0.182 g. (1.03 mmol.) of palladium(II) dichloride, 10 ml. of methylene chloride, 0.233 g.(2.16 mmol.) of 4-methylphenol, 0.320 g. (2.32 mmol.) of potassium carbonate and sufficient carbon monoxide to charge the vessel to 64 psi. The product yield was 5% of 4,4'-dimethyldiphenyl carbonate and 1% of 4'-methylphenyl-2-hydroxy-5-methyl benzoate.
EXAMPLE VIII
Preparation of 4'-methylphenyl-2-hydroxy-5-methyl benzoate using potassium fluoride as a base.
The reaction vessel contained 0.182 g. (1.00 mmol.) of palladium (II) dichloride, lO ml. of methylene chloride, 0.248 g. (2.3 mmol.) of 4-methylphenol, 0.150 g. (2.6 mmol.) of potassium fluoride, and sufficient carbon monoxide to charge the vessel to 65 psi. The product yield was 3% of 4,4'-dimethyldiphenyl carbonate and 1% of 4'-methylphenyl-2-hydroxy-5-methyl benzoate.
EXAMPLE IX
Preparation of phenyl salicylate using rhodium (III) trichloride.
A reaction vessel was charged with 4 g. (42.0 mmol.) of hydroxybenzene and 0.83 g. (4.0 mmol.) of rhodium trichloride, i.e. RhCl3. The mixture was warmed to lO0 C., carbon monoxide was bubbled through the mixture and 2.5 g.
(16.0 mmol.) of 2,2,6,6,N-pentamethylpiperidine was added.
Subsequent workup and analysis showed the presence of diphenylcarbonate (estimated yield 1%) and 0.7 g. (8%) of phenyl salicylate.
EXAMPLES X - XIII
Preparation of phenylsalicylate using a preliminary reaction admixture, i.e. phenol, carbon monoxide and bis-(benzonitrile)palladium(II)dichloride and regulating relative to time the order of addition of a base, e.g.

diisopropylmonoethylamine, to the preliminary reaction admixture.
A series of independent reactions were carried ~ 742 RD 9367 out wherein a preliminary reaction admixture, i.e. a "PRM", was contacted with a base, i.e. diisopropylmonoethylamine,

5, 20, 60 and 120 minutes after the PRM was initially contacted with carbon monoxide. A control run was carried out with base being added at zero minutes, e.g. essentially simultaneously with the formation of the PRM. Three hours after the combination of the PRM ingredients, the resulting reaction products were analyzed and the relative proportions of diphenylcarbonate and phenylsalicylate were determined.
Summarized in Table I are the reaction parameters and products, i.e. the time of addition of the base to the PRM and the resulting reaction products, i.e. the diphenylcarbonate and the phenylsalicylate.
TABLE I

Base Example Run Addition Relative Proportions No. No. Time(min) diphenylcarbonate:phenylsalicylate Control 1.* 0 0.05 : 99.95 X 2. 5 0.25 : 99.75 XI 3.20 5 : 95 XII 4.60 50 : 50 XIII 5.120 100 : 0 * - control run As illustrated by this example, the time and "order of addition" sequence, i.e. time and order o~
addition of base to a PRM in the practice of my process significantly effects the relative proportions and accordingly the yields of diphenylcarbonate and phenylsalicylate obtained~
EXAMPLE XIV
Preparation of phenyl salicylate using palladium (II) dichloride as the Group VIIIB compound and copper(II) 30dichloride as the oxidant under carbon monoxide pressure.
A reaction vessel was charged with ~4 g.(l.0 mole) of phenol, 34.0 g. (0.25 mol) of copper(II~dichloride, 0.45 g.

1124 7~ RD 9367 (0.0025 mol) of palladium(II)dichloride, 147 g. (0.75 mol) cf dicyclohexyl-N-methylamine, and 500 ml. of methylene chloride. The mixture was pressurized with 420 psig CO and heated to 160 C. for 4 hours, cooled and vented. Gas chromatography established the presence of 10.7 g. of phenyl salicylate (5% conversion based on phenol, 40% yield based on CuC12)-In the practice of my process, the Group VIIIBelements after separation from the resulting reaction products can be oxidized or reduced to any suitable oxidation state, and can be re-employed, that is, recycled in the aromatic salicylate process described herein.
Although the above examples have illustrated various modifications and changes that can be made in the carrying out of my process, it will be apparent to those skilled in the art that other Group VIIIB metals, phenolic compounds, ligands, oxidants, redox components, drying agents and solvents as well as other reaction conditions can be effected without departing from the scope of the invention.

Claims (18)

The embodiments of the invention in which an exclu-sive property or privilege is claimed are defined as follows:

1. An aromatic salicylate process which comprises contacting sequentially the following reactant groups:
(a) a phenol, a base, and a Group VIIIB element selected from ruthenium, rhodium, palladium, osmium, iridium or platinum and having an oxidation state of at least +2, and subsequently (b) carbon monoxide.

2. The claim 1 process, wherein the temperature is within the range of from 0°C to 300°C.

3. The claim 2 process, wherein the temperature range is from 0°C to 200°C.

4. The claim 3 process, wherein the temperature range is from 0°C to 100°C.

5. The claim 4 process, wherein the temperature range is from 0°C to 50°C.

6. The claim 1 process, wherein said base is a tertiary amine.

7. The claim 1 process, wherein said element is present in an ionic form.

8. The claim 1 process, wherein said element oxidation state is +2.

9. The claim 1 process, wherein said base is a sterically hindered amine.

10. The claim 1 process, wherein said element is associated with a carbonyl group.

11. The claim 1 process, wherein said element is associated with a halide.

12. The claim 1 process, wherein said element is coordinated with a ligand selected from a nitrile or a halide.

13. The claim 1 process, wherein said element is associated with an inorganic halide compound.

14. The claim 1 process, wherein methylene chloride is employed as a solvent, the base is diisopropylmonoethylamine, the phenol is 4-methylphenol, the Group VIIIB element is palladium in the form of palladium(II) dichloride.

15. The claim 1 process, in which said salicylate is prepared in a methylene chloride solution in which the base is diisopropylmonoethylamine, the phenol is phenol, and the Group VIIIB element is palladium in the form of bis(benzonitrile)-palladium(II) dichloride.

16. The claim 1 process, further comprising, after the preparation of the aromatic salicylate, separating at least a portion of any resulting Group VIIIB element or compound from said salicylate, oxidizing at least a portion of said resulting Group VIIIB element or compound to an oxidation state of at least +2, and recycling at least a portion of the oxidized element or compound in said aromatic salicylate process.

17. The claim 1 process, wherein the Group VIIIB
element is palladium.

18. The claim 16 process, wherein the Group VIIIB
element is palladium.