Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C17/00—Preparation of halogenated hydrocarbons
  • C07C17/093—Preparation of halogenated hydrocarbons by replacement by halogens

Definitions

• the present invention relates to the preparation of 2,3,5,6-tetrahalogen xylylidene compounds by diazotization of 2,3,5,6-tetrahalogen xylylidenediamine.
• 2,3,5,6-tetrahalogen xylylidene compounds are known to the person skilled in the art as important intermediates, for example for the production of pharmaceutical or agrochemical active substances such as insecticides.
• GB-A-21 27 013 describes, for example, the reduction of tetrafluoroterephthalic acid chloride with sodium borohydride to tefrafluoroxylylidenediol and the following Esterification with acetyl chloride to give tetrafluoroterephthalate.
• EP-A-0 152 174 also discloses a complicated reaction sequence in which, starting from 2,3,5,6-tetrafluorotoluene, metalation, methylation, bromination, substitution of the xylylidene dibromide with aluminum acetate and hydrolysis to give 2,3, 5,6-tetrahalogen xylylidenediol arrived.
• the conversion of 2,3,5,6-tetrahalo-xylylidenediamine to 2,3,5,6-tetrahalo-xylylidene compounds with cleavage of the NC bond has not previously been described.
• the object of the present invention was to provide a process which enables industrial preparation of 2,3,5,6-tetrahalogen xylylidene compounds with high space-time yields from simple precursors.
• the invention relates to a process for the preparation of 2,3,5,6-tetrahalogenoxy compounds of the general formula (I)
• shark is the same or different and for fluorine or chlorine and X for fluorine, chlorine,
• HX is particularly preferably used as the solvent, so that 2,3,5,6-tetrahalogen-xylylidene diols are obtained as compounds of the general formula (I).
• the 2,3,5,6-tetrahalo-xylylidenediamines of the formula (II) are diazotized in the process according to the invention in the presence of alkyl nitrites and / or nitrous oxide
• D-Cio-alkyl nitrites have proven themselves as alkyl nitrites; isoamyl, ethyl or methyl nitrite is preferably used, particularly preferably methyl nitrite.
• nitrous acid can also be used. This can also be produced in situ from alkali and / or alkaline earth nitrite and a mineral acid and / or carboxylic acid. In this case, as
• Alkali and / or alkaline earth nitrite preferably calcium, magnesium, sodium or potassium nitrite and preferably used as mineral acid sulfuric, hydrochloric, hydrofluoric, chlorosulfonic, fluorosulfonic or phosphoric acid.
• formic acid, acetic acid, propionic acid or benzoic acid can be used as the carboxylic acid.
• one or more other inert solvents are used in addition to the solvent HX.
• other inert solvents are, for the novel process C 3 -C 0 -, preferably C 6 -C 2 alkane, C 5 -C 30 -, preferably C ö -C cycloalkanes, C 6 -C 2 0 -, preferably C 6 -C 18 aromatics, C 3 -C 30 esters and C 3 -C 30 ethers are suitable.
• Mineral acids and / or carboxylic acids to a value of 0-9, preferably 2-7 and particularly preferably from 3 to 5.
• the compounds already mentioned above for the in-situ preparation of the nitrous acid can be used as mineral or carboxylic acids.
• the process according to the invention is carried out at temperatures of 0-100 ° C., preferably from
• the pressure during the diazotization is 0.2-200 bar, preferably 0.5-50 bar and particularly preferably 1-10 bar.
• the molar ratio of the compounds of formula (II) to alkyl nitrite and / or nitrous acid is 1: (2-10), preferably 1: (2-4).
• the reaction solution has a starting material content of 1-50% by weight, preferably 5-25% by weight.
• the process according to the invention can be carried out batchwise, semi-continuously or continuously in conventional reactors.
• the exact technical design depends on the process parameters and is easy for the person skilled in the art to determine.
• the process according to the invention is therefore carried out in such a way that the compounds of the formula (II) are obtained by hydrogenating compounds of the general formula (III)
• All catalysts known and customary for the hydrogenation of nitriles can be used as hydrogenation catalysts.
• catalysts based on elements of the VIII subgroup have proven successful.
• Hydrogenation catalysts based on rhodium, palladium, ruthenium, nickel, cobalt or platinum are preferably used; palladium contacts are particularly preferred.
• the hydrogenation is also carried out in the presence of one or more solvents HX, where X has the meanings given for the formula (I). If appropriate, further inert solvents can also be present.
• the reaction temperature of the hydrogenation is from -30 to + 60 ° C, preferably 0 to 30 ° C and the pressure is 3 - 300 bar, preferably 10 - 100 bar.
• a process variant which is characterized in that the compound of the formula (II) obtained by hydrogenation is freed from the hydrogenation catalyst by filtration and, if appropriate after distillative removal of troublesome solvent, is fed to the diazotization directly without intermediate isolation is particularly advantageous.
• This reaction solution present after the hydrogenation can be initially introduced and then the diazotization reagent alkyl nitrite and / or nitrous acid are added, but the procedure can also be reversed.
• the process according to the invention provides the desired 2,3,5,6-tetrahaloxylylidene compounds in high purity and with high purity via simple process steps
• 3200 g (2.87 mol of compound) are adjusted to pH 4 with 868 g of 20% sodium hydroxide solution from a solution of tetrafluoro-xylylidenediamine hydrosulfate as prepared above.
• the reaction mixture is heated to 80-90 ° C. and 981 g of a 40% sodium nitrite solution are added dropwise within 4 h.
• the pH of the solution is maintained between pH 3 and pH 5 using 127 g of 30% sulfuric acid.
• the reaction mixture is extracted twice with 750 ml of ethyl acetate and the organic phase is then concentrated in vacuo. 456 g (2.17 mol) of 2,3,5,6-tetrafluoroxylylidenediol are obtained in a purity of 74.5% and a yield of 76%.

Landscapes

• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)

Priority Applications (5)

Applications Claiming Priority (2)

Publications (1)

Family

ID=7628784

Family Applications (1)

Country Status (7)

Cited By (2)

Families Citing this family (1)

Citations (4)

Family Cites Families (8)

• 2000
  • 2000-01-27 DE DE10003320A patent/DE10003320C2/de not_active Expired - Fee Related
• 2001
  • 2001-01-17 WO PCT/EP2001/000446 patent/WO2001055064A1/de not_active Ceased
  • 2001-01-17 JP JP2001555009A patent/JP2003523966A/ja active Pending
  • 2001-01-17 EP EP01907453A patent/EP1254096B1/de not_active Expired - Lifetime
  • 2001-01-17 US US10/181,997 patent/US6753444B2/en not_active Expired - Fee Related
  • 2001-01-17 CN CN01804200.7A patent/CN1396895A/zh active Pending
  • 2001-01-17 DE DE50107987T patent/DE50107987D1/de not_active Expired - Lifetime
  • 2001-01-17 AU AU2001235423A patent/AU2001235423A1/en not_active Abandoned

Patent Citations (4)

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events