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
  • C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
  • C07C29/48—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by oxidation reactions with formation of hydroxy groups
  • C07C29/50—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by oxidation reactions with formation of hydroxy groups with molecular oxygen only
• • 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
  • C07C407/00—Preparation of peroxy compounds
  • C07C407/003—Separation; Purification; Stabilisation; Use of additives
  • C07C407/006—Stabilisation; Use of additives
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C45/00—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds
  • C07C45/27—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by oxidation
  • C07C45/32—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by oxidation with molecular oxygen
  • C07C45/33—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by oxidation with molecular oxygen of CHx-moieties
  • C07C45/34—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by oxidation with molecular oxygen of CHx-moieties in unsaturated compounds
  • C07C45/36—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by oxidation with molecular oxygen of CHx-moieties in unsaturated compounds in compounds containing six-membered aromatic rings
• • 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

• the present invention relates to the oxidation of toluene to benzyl alcohol and benzaldehyde.
• the most widely used industrial process for the preparation of benzyl alcohol and benzaldehyde consists in chlorinating toluene to a mixture of benzyl chloride and benzylidene chloride, which are then saponified.
• the process of the invention comprises oxidizing liquid toluene at 220 C. with gaseous oxygen in the presence of an inert gaseous diluent in amount such that the gaseous mixture contains not more than 21% of oxygen, the oxidation being discontinued when at most 10% of the toluene has been oxidized.
• the diluted oxygen preferably air of reduced oxygen content, is passed through the liquid toluene at a temperature between 170 and 220 C.
• This mixture is then ordinarily de-peroxidized, for example by catalytic hydrogenation or by heating in an inert atmosphere to 180-280 C., or to a lower temperature if the de-peroxidation is accelerated by the use of a de-peroxidation catalyst, such as a cobalt salt or a derivative of boric acid (eg the anhydride, an acid, or an ester).
• a de-peroxidation catalyst such as a cobalt salt or a derivative of boric acid (eg the anhydride, an acid, or an ester).
• the de-peroxidation treatment may optionally be omitted, since adequate deperoxidation generally takes place in the separation of the constituents of the mixture.
• stabilizing agent for organic hydroperoxides so that the decomposition of the benzyl hydroperoxide, which is a primary product of the oxidation, is inhibited.
• the mixture obtained is then subsequently de-peroxidized and separated as already described.
• stabilizing agent the products known for stabilizing hydrogen peroxide may be used, e.g. those appearing in the list given in R. E. Kirk and D. F. Othmer (Encyclopedia of Chemical Technology, Interscience Encyclopedia, New York, vol. 7, p. 730 (1951)). More especially, sodium pyrophosphate and sodium fluoride may be used.
• the proportion of stabilizing agent to be employed is conveniently between 0.01% and 0.5% by weight of the toluene employed.
• the process of the invention gives a mixture of benzyl alcohol and benzaldehyde in yields from 50% when no stabilizer is employed, to 70% when a stabilizer is used.
• EXAMPLE 1 Into a stainless steel autoclave having a capacity of 3.6 litres and provided with a stirring system are introduced 2000 g. of toluene, and a pressure of 10 bars is established with a gas mixture consisting of 10% of oxygen and 90% of nitrogen. After heating to 165 C., when the pressure reaches 12 bars, a current of the same gas mixture is introduced into the reaction mass at a rate of 350 litres per hour, the heating being continued until the temperature reaches -190 C. At the end of one hour, the heating and the passage of the gas mixture are stopped.
• the percentage by weight of the oxidation products is determined on an aliquot fraction of the reaction product by evaporation of the toluene in vacuo, followed by determination of the benzyl hydroper-oxide by iodometry and of the acid products (expressed as benzoic acid) by alkali titration. From the difference, the percentage of the oxidation products other than hydroperoxides and acids is obtained.
• Table I The results are set out in Table I below.
• Example 2 The procedure of Example 1 is followed, but 0.1% by Weight of sodium pyrophosphate is added to the toluene. Analyses, carried out as in Example 1, give the results shown in Table I.
• the benzyl alcohol and the benzaldehyde are then separated from the other oxidation products, by fractional distillation under a vacuum of 7 mm. Hg, the aldehyde passing over at 4950 C. and the alcohol at 8283 C.
• the yields obtained are set out in Table II.
• Example 3 The procedure of Example 1 is followed, but 0.1% by weight of sodium fluoride is added to the toluene.
• the composition of the mixture after oxidation, determined as indicated in Example 1, is given in Table I.
• Process for the production of benzyl alcohol and benzaldehyde which comprises oxidizing liquid toluene at 170 C.220 C. with a mixture of gaseous oxygen and an inert gaseous diluent such that the said mixture contains not more than 21% of oxygen, until at most 10% of the toluene has been oxidized, decomposing the hydroperoxides formed to benzyl alcohol and benzaldehyde by catalytic hydrogenation and separating the benzyl alcohol and benzaldehyde produced.
• Process for the production of benzyl alcohol and benzaldehyde which comprises oxidizing liquid toluene at C.220 C. with a mixture of gaseous oxygen and an inert gaseous diluent such that the said mixture contains not more than 21% of oxygen, until at most 10% of the toluene has been oxidized, decomposing the hydroperoxides formed to benzyl alcohol and benzaldehyde by heating in an inert atmosphere, and separating the benzyl alcohol and benzaldehyde produced.
• Process for the production of benzyl alcohol and benzaldehyde which comprises oxidizing liquid toluene at 170-220 C. with air of reduced oxygen content in the presence of 0.01 to 0.5% by weight of the toluene of sodium pyrophosphate until 4 to 7% by weight of the toluene has been oxidized, decomposing the benzoyl hydroperoxide formed by heating in an inert atmosphere in the presence of a cobalt salt, and isolating benzyl alcohol and benzaldehyde from the product by fractional distillation.
• Process for the production of benzyl alcohol and benzaldehyde which comprises oxidizing liquid toluene at 170-220 C. with air of reduced oxygen content in the presence of 0.01 to 0.5% by weight of the toluene of sodium fluoride until 4 to 7% by weight of the toluene has been oxidized, decomposing the benzoyl hydroperoxide formed by heating in an inert atmosphere in the presence of a cobalt salt, and isolating benzyl alcohol and benzaldehyde from the product by fractional distillation.

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• Oil, Petroleum & Natural Gas (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)
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Citations (3)

• 0
  • NL NL128577D patent/NL128577C/xx active
• 1963
  • 1963-05-22 FR FR935749A patent/FR1366078A/fr not_active Expired
• 1964
  • 1964-05-13 US US367225A patent/US3387036A/en not_active Expired - Lifetime
  • 1964-05-20 GB GB20891/64A patent/GB1027323A/en not_active Expired
  • 1964-05-21 JP JP39028429A patent/JPS495324B1/ja active Pending
  • 1964-05-21 NL NL6405653A patent/NL6405653A/xx unknown
  • 1964-05-21 BE BE648233A patent/BE648233A/xx unknown
  • 1964-05-22 CH CH671064A patent/CH416590A/fr unknown
  • 1964-05-22 DE DER37946A patent/DE1224291B/de active Pending

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