Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D213/00—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members
  • C07D213/02—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members
  • C07D213/04—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members having no bond between the ring nitrogen atom and a non-ring member or having only hydrogen or carbon atoms directly attached to the ring nitrogen atom
  • C07D213/60—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members having no bond between the ring nitrogen atom and a non-ring member or having only hydrogen or carbon atoms directly attached to the ring nitrogen atom with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached to ring carbon atoms
  • C07D213/78—Carbon atoms having three bonds to hetero atoms, with at the most one bond to halogen, e.g. ester or nitrile radicals
  • C07D213/79—Acids; Esters
  • C07D213/803—Processes of preparation

Definitions

• the amount of solvent to be used is preferably 2-6 times by weight, based on the weight of alkyl pyridines, and more preferably, 3-5 times by W ht-1' 1 I
• the reaction pressure should be sufficient to-keep the system in jthej liquid phase, and preferably it is in the range "kg/cm Reaction temperatures of higher than 17010. are required for effecting oxidation with a high conversion, and a temperature in the range of 200250 C. is particularly preferred.
• alkyl pyridine starting material to be used in this invention although pyridine compounds having an aliphatic hydrocarbon radical substituted at the a-position are undesirable, other alkyl pyridines having any number of carbonatoms in the alkyl group may be used without limitatiom'for example, there may be employed fl-picoline,
• alkyl pyridines generally have high boiling points, the recovery ratio is not very high because of oxidation and decomposition on recovery by distillation, and the quality of the product, nicotinic acid, is also affected greatly. Because the conversion of alkyl pyridines to nicotinic acid is so low, there are many economic disadvantages, such as low production rate and high equipment cost.
• the solvent to be used for the liquid phase reaction of this invention is not critical, provided that the solvent is inert in the oxidation condition and that it can dissolve the catalyst system of this invention.
• Lower saturated fatty acids are particularly preferred, and above all, acetic 4-e thylpy'ridine, 3-propyl pyridine, and 4-propyl pyridine.
• the pyridine compound has the formula wherein R R 1 and R is H, or an alkyl having 1 to 3 carbon atoms and at least one of R R and R is said alkyl.
• zirconium compounds, bromine compounds and salts of transition metals more or less show catalytic activity when used alone or as a combination of two components, but a remarkable increase of the catalytic activity is observed when there is used a mixed systemKof these three components, according to this invention.
• All zirconium compounds that dissolve in the solvent show' the catalytic effect, irrespective of the kinds of the anion present.
• suitable zirconium compounds there may be exemplified zirconyl acetate, zirconium v nitrate, zirconium acetylacetonate, zirconium oxide, zirpresent in the initial-stage of the reaction.
• cobalt acetate or manganese acetate or both of-them simultaneouslysAs to the bromine compounds there is no particular limit except that they must be soluble in the solvent, and there may be exem plified ammonium bromide, hydrogen bromide, bromine,
• each catalyst component to be used is preferably about 0.1l0% by weight, based on the weight of the alkyl pyridine starting material, more preferably 0.52.0% by weight.
• the zirconium compound-containing catalyst to be used according to this invention does not show any adverse effect on the quality of the product, and that the catalyst is effective for the air oxidation of the starting material in liquid phase.
• the filtrate was condensed and 58.3 parts of nicotinic acid were obtained as a residue. From the distillate 6 parts of p-picoline were collected. The conversion of ,8- picoline was 95 mol percent; the selectivity of nicotinic acid was 85 mol percent, and the yield of nicotinic acid was 80 mol percent. Nicotinic acid was recrystallized from water to produce a product of high purity having the melting point of 235-236 C. In the case of the same procedure as mentioned above, except that no zirconyl acetate was used, the conversion of p-picoline was 76% and the selectivity of nicotinic acid based on the converted p-picoline was 85%.
• EXAMPLE 2 Oxidation of 'y-picoline was performed in the same way as described in Example 1. When zirconyl acetate was added, there were obtained a conversion of 'y-picoline of i 40 mol percent, a selectivity of iso-nicotinic acid of 80 mol percent, but when no zirconyl acetate was added, the conversion of 'y-picoline was 17 mol percent and the selectivity of iso-nicotinic acid was 80 mol.
• Example 2 The same operation as described in Example 1 was carried out and the anion of the zirconium compound was varied. The results are-shown. in the following table.
• a process for producing pyridine carboxylic acid which comprises oxidizing (1) alkyl pyridine of the formula wherein R R and R is H or alkyl of 1 to 3 carbon atoms, and at least one of R R and R is said alkyl, with (2) molecular oxygen or a molecular oxygen containing gas, in the liquid phase, at a temperature above about 17 C., in the presence of (3) a catalyst consisting essentially of (a) zirconium compound, (b) bromine or a bromine compound and (c) soluble salt of transition metal, the amounts of catalyst ingredients (a), (b) and (0) each being in the range of from 0.1 to 10% by weight, based on the weight of alkyl pyridine, during the oxidation.
• reaction temperature is in the range of 200 to 250 C.

Landscapes

• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Pyridine Compounds (AREA)
• Catalysts (AREA)
• Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=14831221

Family Applications (1)

Country Status (8)

Cited By (5)

Families Citing this family (4)

• 1970
  • 1970-12-30 JP JP45122247A patent/JPS5017068B1/ja active Pending
• 1971
  • 1971-12-24 FR FR7146619A patent/FR2120874A5/fr not_active Expired
  • 1971-12-27 US US00212676A patent/US3801584A/en not_active Expired - Lifetime
  • 1971-12-28 DE DE2165035A patent/DE2165035C3/de not_active Expired
  • 1971-12-28 CH CH1903471A patent/CH532578A/fr not_active IP Right Cessation
  • 1971-12-29 IT IT33108/71A patent/IT944557B/it active
  • 1971-12-29 GB GB6036271A patent/GB1368309A/en not_active Expired
  • 1971-12-29 CA CA131,314A patent/CA949579A/en not_active Expired

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