IL24593A - Process for the preparation of oxirane compounds and phthalic anhydride,or alpha-naphthol,respectively - Google Patents

Description

Process for the preparation of oxirane compounds and phthalic arihydride, or alpha-naphthoi, respectively HALCON UTTERHATIONAL, The present invention is concerned with a new and improved process, for the production of oxirane compounds and other valuable chemical products through the use of an olefin material and tetralin as- raw materials . In a parti-cularly preferred practice, the invention pertains to the concurrent production of an oxirane compound such as propylene oxide together with phthalic anhydride .

Both oxirane compounds and phthalic anhydride are very important and widely used chemicals of commerce. Although various procedures have been employed in the prior art for the separate production of such materials, there remains considerable room for improvement in the economies and efficien¬ cies of the preparation of the materials .

An object of the present invention is topraswide a process for.the concurrent production of an oxirane compound and another valuable chemical employing an olefin material and tetralin as raw materials .

It is a particular object of the invention to provide a process for the preparation of an oxirane compound and phthalic anhydride.

It is a further object to provide a process for the production. of an oxirane compound and alpha naphthol.

It is a special object of the invention to provide a process for the 800 smm concurrent production of propylene oxide and phthalic anhydride. i Other objectsvBvill be apparent from the following description of ' the invention* In accordance with the presence invention/ tetralin is oxidized w molecular oxygen in the liquid phase in order to provide an effluerit which contains tetralin alpha hydroperoxide. The hydroperoxide, in a second reactio step, is reacted with an olefin material under conditions which are effective to produce the oxirane derivatives of said olefin.. At the same time, the tetrali hydroperoxide is reduced to alpha hydroxy tetralin (tetralol) . The reactio mixture is then treated in order to separate various products. Normally, the oxirane compound is desired in highly pure form, and, therefore, the reaction mixture is subjected to treatment as by distillation in order to separate the product oxirane compound,, It is, however, to be understood that such separation is not always necessary since in some instances the oxirane compound can be employed in admixture with various of the other components of the reaction mixture.

The tetralol which is produced by reduction of the tetralin hydroperoxide is then subjected to a reaction to produce a further advantageous product. In the most preferred practice of this invention, the tetralol is oxidized with molecular oxygen to produce phthalic anhydride. In another practice of the invention, the tetralol is dehydrogenated to the valuable · , chemical, alpha hydroxylnaphthalene .

From the above brief overall description of the invention, it can be see that there are certain very distinct advantages which are achieved through the present invention <> In the first place, it is possible tjio form an important a,i¾d valuable oxirane compound employing relatively inexpensive and available raw materials <> However, not only is the oxirane compound formed by the inventive process, but also in forming this compound the other reaction component, tetralin, is upgraded to a more valuable and useful material which itself has high utility in further reactions . For example, the oxirane step results in upgrading tetralin to the more valuable tetralol. Tetralol is a considerably more valuable phthalic anhydride precursor than is tetralin in that improved oxidation selectivities to phthalic anhydride are achieved with tetralol. Thus, it can be seen that the various steps of the present invention cooperate in the unique combination in order to attain unexpectedly advantageous end results .

The tetralin is converted to tetralin hydroperoxide in accordance with techniques which are of a generally known nature . Such techniques involve the liquid phase oxidation of tetralin with a molecular oxygen containing gas . Air is the most advantageously employed as to source of molecular oxygen although mixtures of molecular oxygen with inert gas in greater or lesser concentrations than normally found in air can be used. Oxidation temperatures range generally from 70°C. to 160°C , a preferred range being 90°C . to 115°C . Sufficient pressure is maintained to provide for the tetralin in the liquid phase. Illustrative pressures range from 0 to 500 p. s . i.g. , a preferred range being 0 to 50 p. s .i.g. The tetralin peroxidation is continued preferably until about 10 to 40% of the tetralin has been reacted.

In the olefin epoxidation step, a catalyst is used. i The epoxidation catalysts include compounds of the following: Tf, V, Cr, Se, Zr, Nb, Mo, Te, Ta, W, Re, U. These may be characterized as forming peracids or as hydroxylation catalysts . By far. the preferred catalysts are compounds of V, W, Mo, TO,, Ta, Nb, Re, and Se.

The amount of metal in solution used as catalyst in the epoxidation process can be varied widely, although as a rule it is desirable to use at least about 0.00001 mols and preferably 0.002 to 0. ϋΟ;35 mols per mol of hydroperoxide present. Amount greater than about 0.1 mols seem to give no advantage over smaller amounts, although amounts up to 1 mol or more per mol of hydroperoxide can be employed. The catalysts remain dissolved in the reaction mixture throughout the process and can be reused in the reaction after removal of the reaction products therefrom. The molybdenum compounds include the molybdenum organic salts, the oxides such as M02O3, Mo02» M0O3, molybdic acid, the molybdenum chlorides and oxychlorldes, molybdenum fluoride, phosphate, sulfide, and the like. Hetero-polyacids containing molybdenum can be used as can salts thereof; examples include phosphomolybdic acid and the sodium and potassium salts thereof . Similar or analogous compounds of the other metals mentioned may be used* ¾ may mixtures thereof .

The catalytic components may be employed in the epoxidation reaction in the form of a compound or mixture which is initially soluble in the reaction medium. While solubility will, to some extent depend on the particular reaction medium employed, a suitably soluble substance contemplated by the invention would include hydrocarbon soluble, organo-metallic compounds having a solubility in methanol at room temperature of at least 0.1 gram per liter. Illustrative soluble forms of the catalytic materials are the naphthenate stearates, octdsatfise, carbonyls and the like . Various chelates, association compounds and enol salts, such, for examples, as aceto-acetonates may also be used. Specific and preferred catalytic compounds of this type for use in the invention are the naphthenates and carbonyls of molybdenum, vanadium an tungsten .

As to the substrate, olefinically unsaturated materials which are epoxidized in accordance with the invention include substituted and unsub-stituted aliphatic and alicyclic olefins which may be hydrocarbons or esters o alcohols or ketones or etlters or the like. Preferred compounds are those havi from about 2 to 30 carbon atoms, and preferably at least 3 carbon atoms .

Illustrative olefins are ethylene, propylene, norma 1 butylene, isobutylene, th pentenes, the methyl pentenes> the normal hexenes, the octenes, the dodece cyclohexene, methyl cyclohexene, butadiene, styrene, methyl styrene, vinyl toluene, vinylcyclohexene, the phenyl cyclohexene s, and the like . Olefins having halogen oxygen, sulfur and the like containing substituents can be use such substituted olefins are illustrated by allyl alcohol, methallyl alcohol, cyclohexanol, diallyl ether, methyl methacjylate, methyl oleate, methyl vinyl ketone, allyl chloride, and the like . In general, all olefinic material epoxidi by methods previously employed can be epoxidized in accordance with this pr cess including olefinically unsaturated polymers * .

The lower olefins having about 3 or 4 carbon atoms in an aliphatic chain are especially advantageously epoxidized by this process . · ; ; In the oxidation of the substrate, the ratio of substrate to organic peroxy compounds can vary over a wide range . Generally, mol ratios of ole-finlc groups in the substrates to hydroperoxide broadly in the range of 0.6:1 to 100:1, desirably hi to 20:1 and preferably 2: 1 to 10:1 are employed.

The concentration of hydroperoxide in the substrate oxidation reaction mixture at the beginning of the reaction will normally be one percent or more although lesser concentrations will be effective and can be used.

The substrate oxidation reaction can be carried out in the presence of a solvent, and in fact, it is generally desirably that one be used. In general, aqueous solvents are not contemplated. Among the suitable substances are hydrocarbons, which may be aliphatic, naphthenic or aromatic, and the oxygenated derivatives of these hydrocarbons . Preferably, the solvent has the same carbon skeleton as the hydroperoxide used, so as to minimize or avoid solvent separation problems .

Basic substances can be employed in the epoxidation. Suitable substances are alkali metal compounds or alkaline earth metal compounds . Particularly preferred are the compounds of sodium, potassium, lithium, calcium, magnesium, rubidium, cesium, strontium and barium. Compounds which are employed are those which most preferably are soluble in the reaction medium. However, insoluble forms can be employed and are effective when dispersed i the reaction medium. Organic acid compounds such as a metal acetate, naph thenate, stearate, octoate, butyrate, and the like can be employed . Addition ally inorganic salts such as Na carbonate, Mg carbonate, trisodium phosphat and the like can also be employed. Particularly preferred species of metal salts include sodium naphthenate, potassium, stearate, magnesium carbona and the like . Hydroxides and oxides of alkali and alkali earth metal comi o can be used. Examples are NaOH, MgO, CaO, Ca(OH) 2» O. and the like, alkoxides, e .g. , Na ethylate, K cumylate, Na phenate etc. can be used.

Amides such as Na NH can be used as can quaternary ammonium salts . In general, any compound of alkali or alkali earth metals giving a basic reacti in water can be used.

The compound is employed during the epoxidation reaction in amount .05 to 10 mols/raol of epoxidation catalyst desirably .25 to 3.0 and prefera .50 to 1.50. It has been found that as a result of the incorporation of the basic compound in the reaction system, significantly improved efficiencies in the utilization of the organic hydroperoxides in the epoxidation afe achie The epoxidation effluent is desirably treated for the separation of the various components . Suitably the mixture is distilled in order to separate an oxirane compound product as well as the tetralol product. This latter product is then subjected to further reaction to produce an additional valuable chemical.

In preferred practice of the invention, the tetralol from the epoxidatio effluent is oxidized with molecular oxygen in the vapor phase to produce phthalic anhydride . The conditions which are employed in this oxidation are much the same as those which have previously been employed in processes for the oxidation of naphthalene to phthalic anhydride . This oxidati may involve the use of a vanadium pentoxide catalyst, usually on a suitabl support. Co, Mo, Cu and other known oxidation metals are suitably used also. Airis the preferred source of molecular oxygen although oxygen alone/ j '.!; or various concentration in inert gas can also be employed. Suitable temper atures range from about 300° to 65G°C . with 400° to 500°C . being preferred. The pressure is normally about atmospheric although pressures in the range 0 to 500 p. s . i .g . are generally suitable . It is preferred to employ a large molar excess of molecular oxygen in carrying out the reaction. A range of about 10-150:1 mols air per mol tetralol is preferred.

The product phthalic anhydride is recovered in accordance with genera known techniques such as are described in U» S. Patent 3084914.

The yield of phthalic anhydride which is obtained from tetralol is significantly improved as compared with yields obtainable from tetralin.' Normally, yield improvements ranging from 5 to 15% are achieved using tetralpl as contrasted with tetralin. Thus, the outstanding and advantageous nature of the invention can be seen .

In a somewhat less preferred although quite valuable embodiment of th invention, the product tetralol is dehydrogenated to the important chemical alpha naphthol. The dehydrogenation is carried out preferably in the presen of hydrogen, and attenperatures ranging from about 25Q C . to 475°C. and pressures between about 100 mm. and 3 atmospheres , More desirable tempe atures are 325°C * to 40C°C . with 375°C . at atmospheric pressure being es- pecially preferred .

The liquid hourly space velocity of the charge mixture to the dehydroenation is broadl 0.3 to 2.5, desirabl 0.6 to 1 and referabl 0.7 to 0.8 The mol ratio of hydrogen is in the range of 1 to 15 and desirably 4tto 8 mols of hydrogen per mol of tetralol.

• · ■ ^ The preferred dehydrogenation catalyst is platinum on carbon wherein" the catalyst comprises about 0.5 to 5% by weight platinum on carbon. How ever, other dehydrogenation catalysts including nickel, palladium, cobalt, copper, chromium ,zinc, and the like can be employed.

The conversion of the tetralol to alpha naphthol is maintained at abou 50 to 100% and preferably at least 75% per pass .; The following examples illustrate the invention: ' EXAMPLE I Tetralin in the liquid phase is oxidized with air at a temperature of 115 °C . and atmospheric pressure. The oxidation is continued until about 35% "of the tetralin is reacted. The molar selectivity to tetralin hydroperoxi is 85% .

About 39.3 gms . of tetralin oxidate containing 33 wt. % tetralin alpha hydroperoxide are admixed with about 0.4 gms . of molybdenum, naphthenate (5 wt. % Mo), 51.5 gms . of propylene and 11.0 gms . of tertiary butyl alcoho The reaction is run at 90°C . in a closed pressure autoclave. The reaction time is 1 hour.

Conversion was 89.4% based on hydroperoxide and selectivity to propylene oxide was 45.7% . The selectivity to tetralol was 85% based o converted hydroperoxide .

The reaction mixture was distilled and propylene oxide recovered overhead.

• ' / . The bottom fraction from the distillation containing tetralin and tetralol which was formed, both in the peroxidation and as a result of reduction of the hydroperoxide, was distilled and the overhead tetralin product was con-densed and returned to the peroxidation step. The bottoms tetralol fraction was vaporized, mixed with air to a mixture comprising the volume 1.5% tetralol and passed over a vanadium pentoxide on alumina (5% vanadium pentoxide) catalyst at 4Q0°C , 18 p . s . i . g . and 2000 space velocity, hours - 1.

The reaction effluent is condensed in order to separate phthalic anhydride from various other gaseous products . The yield of phthalic anhydride is 97 mol % based on tetralol. Tetralol conversion during the above'oxid-ation is substantially completed .

EXAMPLE H Example 1 is repeated except that the bottoms tetralol fraction, instead of being oxidized to phthalic anhydride is converted to alpha naphttarJ The bottoms tetralol fraction is vaporized, admixed with hydrogen, and passed over a 2% platinum in carbon dehydrogenation catalyst at 375 ° C: and O p. s .i . g. The liquid space velocity is 0.7 . About 5 mols hydrogen are used per mol tetralol.

Conversion of tetralol is 95% and the molar selectivity to alpha naph-thol is 93% .

EXAMP II amount as epoxldatlon catalyst. Similar results are achieved.

EXAMPLE IV Example 1 is repeated using tetrabutyl titanate in equivalent molar amou as epoxidation catalyst. Similar results are achieved.

EXAMPLE Example 1 is repeated using tungsten carbonyl in equivalent molar amou as epoxidation catalyst. Similar results are achieved.

EXAMPLE VI Example 1 is repeated using tantalum naphthenate in equivalent molar amount as epoxidation catalyst. Similar results are achieved.

EXAMPLE VII Example 1 is repeated using niobium naphthenate in equivalent molar amount as epoxidation catalyst. . Similar results are achieved .

EXAMPLE VIII Example 1 is repeated using rhemium heptoxide in equivalent molar amounts as epoxidation catalyst. Similar results are achieved. ■ '., · .

EXAMPLE IX ' Example 1 is repeated using selenium naphthenate in equivalent molar amounts as epoxidation catalyst. Similar results are achieved. ■

Claims (1)

1. TO of our in what the that In a process for the preparation of phthalic the steps of reacting hydroperoxide and an unsaturated compound form an oxlrane compound and alpha and oxidizing said alpha tetralo in the vapor phase to phthalic anhydride In a process for the preparation of alpha the steps of reacting and an olefinically unsaturated compound to form compound and alpha and converting said alpha ixalol to alpha 3 The process of claim 1 wherein the olefinically unsaturated compoun propylene The process of claim 2 wherein the olefinically unsaturated compoun is propylene 5 The process of claim 1 wherein tetralln is oxidized in the liquid phase with molecular oxygen said tetra hydroperoxide The process of claim 2 wherein tetralin is oxidized in the liquid said phase with molecular oxygen to orm tetralin hydroperoxide 7 process of claim 1 wherein a molybdenum catalyst is the said reaction to form said oxlrane compound and alpha 800 insufficientOCRQuality