Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C409/00—Peroxy compounds
  • C07C409/02—Peroxy compounds the —O—O— group being bound between a carbon atom, not further substituted by oxygen atoms, and hydrogen, i.e. hydroperoxides
  • C07C409/04—Peroxy compounds the —O—O— group being bound between a carbon atom, not further substituted by oxygen atoms, and hydrogen, i.e. hydroperoxides the carbon atom being acyclic
  • C07C409/08—Compounds containing six-membered aromatic rings
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C407/00—Preparation of peroxy compounds
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
  • C07C51/16—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation
  • C07C51/21—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation with molecular oxygen
  • C07C51/255—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation with molecular oxygen of compounds containing six-membered aromatic rings without ring-splitting
  • C07C51/265—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation with molecular oxygen of compounds containing six-membered aromatic rings without ring-splitting having alkyl side chains which are oxidised to carboxyl groups

Definitions

• An oxidation product comprising an oily layer containing a tertiary hydroperoxide of a secondary alkyl toluene and an aqueous layer containing a sodium or potassium salt of a secondary alkyl benzoic acid is obtained by reacting a secondary alkyl toluene with oxygen in the presence of water and a carbonate or bicarbonate containing sodium or potassium in an amount of 0.12 atomic equivalent or more per mole of the secondary alkyl toluene, or a mixture thereof, or in the presence of water and a mixture of salts obtained by replacing up to 90% of said carbonate or bicarbonate with a sodium or potassium salt of a secondary alkyl benzoic acid, until the concentration of hydroperoxide in the oily layer formed has become -25% by weight or more.
• cresols are obtained.
• the secondary alkyl benzoic acids in the aqueous layer are further oxidized, benzene dicarboxylic acids are obtained.
• cresols are consumed in large quantities 'as starting materials for preparation of synthetic resins, agricultural chemicals and the like. Cresolshave chiefly been obtained by extraction using petroleum or coal tar as astarting material. Further, benzene dicarboxylic acids, i.e. phthalic acid, terephthalic acid and isophthalic acid, are'important compounds as starting materials of synthetic fibers and synthetic resins, and hence are demanded in enormous amounts. The benzene dicarboxylic acids are chiefly prepared at present by the oxidation of xylenes.
• Ketone compound Secondary alkyl- Formaldehyde substituted phenol (HCHO) Resinous substance wherein R and R represent individually lower primary alkyl groups.
• 2,728,797 and 2,779,797 disclose processes for preparing cresols in which an extraction step is provided between the oxidation step and the cleavage step in order to remove the primary hydroperoxide, or the primary hydroperoxide is previously decomposed by means of caustic soda, so that the tertiary hydroperoxide may be cleavaged with an acidic catalyst in the absence of the primary hydroperoxide.
• Patent but, conversely, by promoting the oxidation of the methyl group of a secondary alkyl toluene to a carboxyl group via the primary hydroperoxide without decomposition of the tertiary hydroperoxide. That is, the inventors found a method for producing a tertiary hydroperoxide substantially free from a primary hydroperoxide by progressing the oxidation of a secondary alkyl toluene in the presence of water and excess alkali until the concentration of hydroperoxide in the oily layer formed became 20% or more.
• An object of the present invention is to provide a method of oxidizing secondary alkyl toluenes to produce synthetic cresols with advantages.
• the present invention provides a method of oxidizing secondary alkyl toluenes, characterized in that a secondary alkyl toluene having the formula,
• R and R are respectively lower primary alkyl groups, is allowed to react at 50-150 C. with oxygen in the presence of water and of a carbonate or bicarbonate containing sodium or potassium in an amount of 0.12 atomic equivalent or more per mole of said secondary alkyl toluene, or a mixture thereof, or in the presence of a mixture of salts obtained by replacing up to of said carbonate or bicarbonate with a salt of a benzenecarboxylic acid, until the content of hydroperoxide in the oily layer formed has become 15-25% (weight), thereby producing a hydroperoxide having the formula,
• secondary alkyl toluenes employed in the present method are isopropyltoluenes secondary butyltoluenes and secondary pentyltoluenes.
• Particularly preferable is isopropyltoluene, and any isomers thereof, i.e. metaand para-form, are usable,
• the oxygen source usable in the present invention may be any of oxygen gas and air.
• the amount of oxygen-required varies depending on the content of hydroperoxide in the oxidation product.
• the carbonate or bicarbonate of sodium or potassium employed in the present method is soda ash, sodium bicarbonate, potassium carbonate, potassium bicarbonate, sodium potassium carbonate or a mixture thereof.
• the amount of the carbonate or bicarbonate ofsodium or potassium employed is such that the amount ;of the sodium or potassium is 0.12 atomic equivalent or more per mole of the secondary-alkyl toluene used.
• the present method can be effectively carried out even when a part of the sodium or potassium in the form of carbonate or bicarbonate is present in the form of a carboxylate.
• the resulting tertiary hydroperoxide is stable and the primary hydroperoxide is converted to the carboxylic acid.
• an acidic substance is formed, and therefore the residual presence of the carbonate or bicarbonate of sodium or potassium is indispensable in order to maintain the oxidation reaction system in a basic condition.
• the objects of the invention can be achieved even if up to about 90% of sodium or potassium is used in the form of a carboxylate and the balance of about is used in the form of a carbonate or bicarbonate.
• Usable as such carboxylic acid is benzenecaroxylic acid having the formula,
• Carboxylic acids obtained by the oxidation of secondary alkyl toluenes include toluic acids, secondary alkylbenzoic acids, and those in which the secondary alkyl groups have been oxidized to alkylketone, hydroxyalkyl, alkenyl and carboxyl groups.
• the amount of water employed in the present method is such that the weight ratio of water to secondary alkyl toluene is from 10:1 to 1:10. Particularly, the reaction progresses advantageously when the weight ratio is within the range of from 3:1 to 1:3.
• the oxidation is advanced until the amount of hydroperoxide in the oily layer formed in the oxidation product has reached 15-25% by weight.
• the reaction rate becomes higher with increasing reaction temperature.
• the reaction temperature is 50-150 C., preferably 75 125 C.
• the reaction progresses either at atmospheric pressure or under pressure, and the reaction rates increases with increasing pressure. Generally, however, a pressure from atmospheric to 30 kg/cm. is adopted.
• reaction times varies depending on the reaction conditions, but a reaction time of 5 to 70 hours, generally 10-30 hours is sufficient.
• the reaction is carried out in an unhomogeneous phase comprising a secondary alkyl toluene and water, the use of an emulsifier is preferable, and lauric acid, palmitic acid, stearic acid or the like surface active agent may be used.
• reaction proceeds even in the absence of catalyst, but a catalyst such as cobalt-amine complex salt, phthalocyanine copper or molybdenum disulfide may also be used.
• a catalyst such as cobalt-amine complex salt, phthalocyanine copper or molybdenum disulfide may also be used.
• the present method may be effected in any of batchwise or continuous manner.
• a secondary alkyl toluene and an aqueous carbonate or bicarbonate solution containing a given amount of sodium or potassium are charged into a reaction vessel, and the mixture is subjected to oxidation reaction. After completion of the reaction, the reaction mixture is allowed to stand to separate an oily layer and an aqueous layer, and then only the oily layer is taken out.
• a fresh secondary alkyl toluene is charged to again effect the oxidation reaction, and the aqueous layer is repeatedly used until about of the carbonate or bicarbonate of sodium or potassium in the aqueous layer has converted into secondary alkyl benzoates.
• a secondary alkyl toluene and an aqueous carbonate or bicarbonate solution of sodium or potassium are fed in definite amounts to an oxidation reaction vessel. Subsequently, an oily layer and an aqueous layer flowing out of the reaction vessel are separated each other and, from the separated aqueous layer, an aqueous solution containing a secondary alkyl benzoate of sodium or potassium is withdrawn in a definite amount each time.
• an aqueous carbonate or bicarbonate solution containing sodim or potassium in an amount coresponding to the amount of the withdrawn sodium or potassium is added to the remaining separated aqueous layer containing the aforesaid secondary alkyl benzoate, and the mixture is again recycled to the oxidation reaction vessel, whereby the object of the reaction can be achieved.
• the oily layer readily separates from the aqueous layer.
• the oily layer comprises unreacted secondary alkyl toluene and a tertiary hydroperoxide thereof.
• the aqueous layer contains a sodium or potassium salt of a secondary alkyl benzoic acid formed by oxidation of the methyl group of the starting secondary alkyl toluene, and a carbonate or bicarbonate of sodium or potassium or a salt of a benzenecarboxylic acid.
• the tertiary hydroperoxide When cleavaged in the presence of a catalyst, the tertiary hydroperoxide is converted into a cresol and an aliphatic ketone.
• a catalyst there is used such an acidic catalyst as sulfuric acid, perchloric acid, sulfurous acid or acidic ion exchange resin.
• the amount of catalyst used is 0.05 to 5% by weight based on the amount of hydroperoxide.
• the reaction temperature is from 50- C., and the reaction time is 15 mintues to 3 hours.
• the hydroperoxides obtained according to the present process are essentially composed of only tertiary hydroperoxides. When the hydroperoxides are cleavaged, therefore, cresols are obtained in amounts of 90-99% of the theoretical amount, i.e. in substantially quantitative yields.
• the aqueous layer is charged with a cobalt, manganese or vanadium system catalyst and is oxidized under such conditions as 200300 C. and 20-50 kg./cm. or it is acidified to separate out a secondary alkyl benzoic acid, which is then taken out of the Water layer. Subsequently, the said acid is oxidized by addition of nitric acid or is treated in an acetic acid solvent at 150-250 C. under 5-30 l g./cm. in the presence of a cobalt or manganese system catalyst to form isophthalic acid or terephthalic acid.
• composition of o-, mand p-isomers of the alkyl toluene does not change in the formation of cresols and phthalic acids in the present invention.
• the conventional process for the oxidation of secondary alkyl toluene have intended to inhibit the oxidation of methyl groups of the secondary alkyl toluenes, or have adopted a step of separating tertiary hydroperoxide from primary hydroperoxides which have been formed by the oxidation of said methyl groups.
• the present invention is concerned with a method in which the secondary alkyl groups of secondary alkyl toluenes are oxidized to tertiary hydroperoxides and, at the same time, the primary hydroperoxide which is formed by the oxidation of methyl group thereof is also oxidized to carboxyl group to obtain secondary alkyl benzoic acid without the decomposition of the tertiary hydroperoxide. Consequently, hydroperoxides which give cresols in high yields in the presence of acidic catalyst, and secondary alkyl benzoic acids which give benzene dicarboxylic acid by further oxidation can be produced simultaneously.
• the starting secondary alkyl toluenes can be converted into cresols and isophthalic and terephthalic acids. Further, it may be said that in accordance with the present method, the position of said toluene as starting materials for the production of cresols and benzene dicarboxylic acids, which are main materials in the field of chemical industry, has been further eletvated. Moreover, the fact that benzenecarboxylates are usable in the present method is a great advantage and further enhances the value of the present invention.
• the aqueous layer is repeatedly used until about 90% of said carbonate or bicarbonate contained therein has been consumed due to c-arboxylic acid formed by the oxidation reaction.
• the aqueous layer can be repeatedly used several times to ten several times, in general, though said times vary depending on the oxidation reaction conditions, and thus the proportion of the carbonate or bicarbonate of sodium or potassium, which proportion occupies the production costs of cresols, can be reduced to a great extent.
• the repeated use of the aqueous layer without removing by-produced carboxylates not only makes it possible to stabilize the resulting tertiary hydroperoxides to increase the yields of cresols, but also makes accurate the formation of secondary alkyl benzoic acid derivatives, which are starting materials of benzene dicarboxylic acid employed for the production of synthetic resins and synthetic fibers. If the repeated use of the aqueous layer is impossible, only a small amount of secondary alkyl benzoic acid is separated after neutralizing a large amount, per unit of the aqueous layer, of the carbonate or bicarbonate of sodium or potassium.
• the concentration of hydroperoxide in the oily layer was 20.5%.
• up to 0.5 part of methylacetophenone and tolyldimethylcarbinol were also observedin the oily layer.
• This oily layer was charged with 0.1 part of concentrated sulfuric acid and was heated at 60 -65 C.'for1 hour, whereby the hydroperoxide was clealvaged to obtain 12.8 parts of cresol and 6.8 parts of acetone.
• the yield of cresol based on the hydroperoxide was 97%, while that of the acetone was 96%.
• the aqueous layer was acidified with sulfuric acid and a separated oily layer was'extracted with toluene to obtain 6.4 parts of cuminic acid (isopropyl benzoic acid).
• cuminic acid isopropyl benzoic acid
• acetylbenzoic acid was contained, the toluic acid, isophthalic acid and terephthalic acid were also detected, though the amounts thereof were extremely slight.
• 20 parts of acetic acid and 1 part of cobalt acetate were added. The resulting mixture was fed to an autoclave and was subjected to oxidation reaction for 15 hours under the reaction conditions of 180 C. and 20 kg./cm.
• EXAMPLE 2 Into a pressure, continuous oxidation reactor provided With a stirrer, an air-blowing pipe, a gas-outlet pipe, a thermometer and a condenser, 100 parts/hr. of cymene, 0.1 part/hr. of stearic acid, 12 parts/hr. of potassium carbonate and parts/hr. of water were fed, and oxidation reaction was initiated, while blowing air, at a temperature of 95 C. under a pressure of 20 kg./cm. Thereafter, the reaction product was taken out at a rate of 296 parts/hr., while controlling the average retention time in the reaction system to 10-12 hours.
• the reaction product was composed of 100 parts of an oily layer and 196 parts of an aqueous layer. After withdrawing 39.2 parts of the aqueous layer, 2.4 parts of potassium car: bonate and 36 parts of water were added to the remaining aqueous layer. The thus prepared aqueous layer was recycled at a rate of 195.2 parts/hr., together with 100 parts/hr. of cymene, to the oxidation reactor to effect continuous oxidation reaction. After the reaction system had reached an equilibrium state, 20.4 parts of hydroperoxide and 79 parts of unreacted cymene were detected in 100 parts of an oily layer flowing out of the reactor. Further, 4.5 parts of cuminic acids were detected in 39.2 parts of the withdrawn aqueous layer.
• R and R respectively represent lower primary alkyl groups, characterized in that the secondary alkyl toluene is reacted with oxygen at 50-l50 C. in water and in the presenceof a carbonate or bicarbonate of sodium. or potassium which contains sodium or potassium in an amount of at least 0.12. atomic equivalent per mole of said secondary alkyl toluene, or a mixture thereof, or in the presence of a mixture of salts of sodium or potassiurnwhich is obtained by replacing up to 90% of sodium or potassium in the form of said carbonate or bicarbonate with one in the form of a sodium or potassium salt of a benzene-carboxylic acid having the formula,
• R is a hydrogen atom, a carboxylic group, a methyl group, or a secondary alkyl group of carbonyl group, a hydroxyalkyl group or alkenyl group derived from the above mentioned secondary alkyl group,
• reaction is effected in the presence of palrnitic acid or stearic acid as an emulsifier.
• R and R are respectively lower primary alkyl groups, is reacted with oxygen at 50-150 C. in water and in the presence of a carbonate or bicarbonate of sodium or potassium which contains sodium or potassium in amount of at least 0.12 atomic equivalent per mole of said secondary alkyl toluene, or a mixture thereof, or in the presence of a mixture of salts of sodium or potassium which is obtained by replacing up to 90% of sodium or potassium in the form of said carbonate or bicarbonate with that in the form of a sodium or potassium salt of a benzenecarboxylic acid having the formula,
• a method according to claim 8 wherein a part of the aqueous layer, which contains the carbonate or bicarbonate of sodium or potassium and sodium orpotas sium salt of the 'benzenecanboxylicacid, is withdrawn, an aqueous solution of a carbonate or bicarbonate of sodium or potassium containing sodium or potassium in an amount correspondingto the amount" of the withdrawn sodium or potassium is added to the remaining separated aqueous layer, and the resulting mixture is again recycled in the oxidation reaction.

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  • NL NL136650D patent/NL136650C/xx active
• 1968
  • 1968-10-08 US US765969A patent/US3647866A/en not_active Expired - Lifetime
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  • 1968-10-14 DE DE19681803036 patent/DE1803036A1/de active Pending
  • 1968-10-14 FR FR1596609D patent/FR1596609A/fr not_active Expired
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