Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07B—GENERAL METHODS OF ORGANIC CHEMISTRY; APPARATUS THEREFOR
  • C07B35/00—Reactions without formation or introduction of functional groups containing hetero atoms, involving a change in the type of bonding between two carbon atoms already directly linked
  • C07B35/04—Dehydrogenation
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C253/00—Preparation of carboxylic acid nitriles

Definitions

• the present invention relates to a process for oxidizing an organic compound, and particularly to a process for oxidizing an amine to the corresponding nitrile. More particularly, it relates to the use of nickel peroxide for the oxidation of the amine having a structure represented by the formula: CH NH in the molecule to the corresponding nitrile having a structure represented by the formula: CN in the molecule.
• nickel peroxide is expediently applied to designate the black, hydrous, higher oxides of nickel which are formed by reaction between a strong oxidizing agent, such as alkali hypohalites or alkali persulfates, and freshly precipitated nickelous hydroxide.
• a strong oxidizing agent such as alkali hypohalites or alkali persulfates
• the oxidation reaction proceeds up to aldehydes by the use of potassium permanganate [Goldschmitt, Ann, 435, 271 (1923) or it is interrupted at the stage of imines by the use of manganese dioxide [Highet et al., J. Am. Chem. Soc., 77, 4399 (1955)].
• a primary object of the present invention is to embody a process for oxidizing an amine to the corresponding nitrile.
• Another object of the invention is to embody a utilization method of nickel peroxide as an oxidizing agent suitable for the conversion of amines into nitriles.
• the process of the present invention comprises treating the amine having a structure represented by the formula: -CH NH in the molecule with nickel peroxide in a hydrous or anhydrous medium to give the corresponding nitrile having a structure represented by the formula: -CN in the molecule.
• the starting amine may be employed in the free state or in the form of salt.
• the salt is em- 3,225,080 Patented Dec. 21, 1965 ICC ployed, it is preferred to change the salt to the free state by the addition of an equivalent or slightly excess amount of a basic substance in advance of the oxidation reaction.
• the nickel peroxide possessing a high oxidizing activity may be prepared by treating a nickel salt (e.g. nickel chloride, nickel sulfate, nickel carbonate, nickel nitrate) with a strong oxidizing agent such as alkali hypohalites (e.g. sodium hypochlorite, potassium hypochlorite, sodium hypobromite) or alkali persulfates (e.g. sodium persulfate, potassium persulfate) in an aqueous alkaline medium.
• alkali hypohalites e.g. sodium hypochlorite, potassium hypochlorite, sodium hypobromite
• alkali persulfates e.g. sodium persulfate, potassium persulfate
• NiSO,-6H O nickel sulfate hydrate
• sodium hydroxide 42 g.
• 6% sodium hypochlorite 300 m1.
• the black precipitate is collected by filtration, washed with water to remove active chlorine and, after crushing the cake to powder, dried over anhydrous calcium chloride under reduced pressure.
• the nickel peroxide is a black fine powder containing several amounts of water.
• the results of the quantitative analysis make it possible to give the molecular formula: Ni O -3H O or Ni(OH) to the oxidant, but the structure has not yet been confirmed.
• the nickel peroxide possesses usually about 0.30.4 10 g.-atom of available oxygen per gram (measured by titrating the iodine, produced from the reaction between the nickel peroxide and potassium iodide in acetic acid, with sodium thiosulfate), of which a considerable portion is lost gradually when heated, but remains for a long time when stored at room temperature under protection against atmospheric moisture.
• the available oxygen can be used elfectively in the oxidation reaction. Owing to this character of the reagent, the present oxidation. can advantageously be completed in a short time normally with one to two equivalent amounts of the oxidant.
• the optimum reaction conditions such as reaction medium, reaction temperature, reaction time and amount of the oxidant are more or less associated with the kind of the starting amines. Therefore, the preferable conditions may be decided on each case.
• the reaction medium there may be exampled water, a neutral inert organic solvent (e.g. benzene, toluene, ether, tetrahydrofuran, petroleum ether) and a mixture thereof.
• a neutral inert organic solvent e.g. benzene, toluene, ether, tetrahydrofuran, petroleum ether
• the reaction is ordinarily carried out from 30 to C., the higher or lower temperature is also operative, provided that the amount of the oxidant is proper.
• the reaction time may be from 30 minutes to 6 hours, normally from 1 to 3 hours.
• the oxidant is employed usually from 1 .to 1.7 times the theoretical amount. As the large excess of the oxidant rather results in the poor yield of the product, .the amount is desired to be at the most two times the theoretical amount.
• the present process has an advantage that the oxidant can be readily separated from the reaction mixture by a simple operation, e.g. filtration.
• the reaction mixture may be shaken with a suitable water-immiscible organic added nickel peroxide 1.5 times the theoretical amount), and the resulting mixture is stirred for 1.5 hours at 60 C.
• the reaction mixture is shaken with ether.
• the ether extract is evaporated and the residue is crystallized from solvent whereby only the reaction product is retained in hexane to give 4-methoxybenz-onitrile (2.8 g.) melting at the organic solvent layer. 58 to 59 C.
• the nickel peroxide employed in the oxidation reaction Example 4 can be i t g by s if profedure 2g. g
• the amount f the oxidant to be empbyed may b 30 hypochlorite (30 g.) dropwise with stirring at 60 C., much decreased and the resultant mixture is heated for 40 minutes at
• the following examples set forth illustratively presenth Same temperature-
• the abbreviations have the following sigmmle nificances: g., gram(s); ml., millilitre(s); and C., de- 35
• Other abbreviations have conventional In the similar manner as shown in the above examples, significances. there are obtained the following results:
• Example 1 A mixture of benzylamine (4.28 g.) and nickel peroxide (34.6 g.) in benzene (100 ml.) is refluxed for 1.5 hours while stirring. Then, the reaction mixture is filtered to separate the oxidant and the filtrate is dried and evaporated to give the residue, which is distilled to give bonzonitrile (3.08 g.) boiling at 185 to 191 C.
• Example 3 To a solution of 4-methoxybenzylamine hydrochloride (4.2 g.) in water (150 ml.), there is added sodium hydroxide whereby 4-methoxybenzylamine is obtained in the form of free base. To the resultant solution, there is The process of the present invention is generally applicable to the production of a nitrile from the corresponding primary alkyl and aryl amines. For instance, it can be adopted for the oxidation of methallylamine to methacrylonitrile, the latter being useful as a starting material in the production of synthetic rubbers and synthetic resins.

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• 1962
  • 1962-10-02 FR FR911041A patent/FR1350668A/fr not_active Expired
  • 1962-10-02 GB GB37384/62A patent/GB955129A/en not_active Expired
  • 1962-10-02 US US227723A patent/US3225080A/en not_active Expired - Lifetime
  • 1962-10-03 DE DES81883A patent/DE1232585B/de active Pending

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