Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C2/00—Preparation of hydrocarbons from hydrocarbons containing a smaller number of carbon atoms
  • C07C2/02—Preparation of hydrocarbons from hydrocarbons containing a smaller number of carbon atoms by addition between unsaturated hydrocarbons
  • C07C2/50—Diels-Alder conversion
  • C07C2/52—Catalytic processes
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C2601/00—Systems containing only non-condensed rings
  • C07C2601/12—Systems containing only non-condensed rings with a six-membered ring
  • C07C2601/16—Systems containing only non-condensed rings with a six-membered ring the ring being unsaturated

Definitions

• This invention relates to a process for the production of dimers of 1,3-butadiene, specifically 4-vinylcyclohexene. More particularly, the invention is directed to an improved catalyst system which, in the presence of a conventional diluent and polymerization inhibitor, can produce 4-vinylcyclohexene with relatively high yields, for example, 84% to 91% based on the weight of reacted butadiene.
• catalyst systems described in the prior art include oxides, complex carbonyl compounds, olefins, metal salts, secondary aliphatic amines, metals, as well as ultra-violet radiation. Of those listed herein, the most effective have been found to be dialkyl amines (discussed in US. Pat. No. 2,943,117), metal salts (discussed in US. Pat. No. 2,544,808), and metal, such as iron powder (discussed in German Pat. No. 949,466).
• Catalyst systems which may be employed are (1) secondary aromatic amines; (2) metal acetylacetonates; (3) mixtures of (1) and (2); or (4) mixtures of (2) and triphenylphosphine.
• the process is carried out in the presence of up to 60%, based on the weight of the 1,3- butadiene, or inert diluent, preferably 12 to 34% by weight, at a pressure of atmospheric to 650 p.s.i., preferably 220 to 410 p.s.i., and at a temperature of 100 to 170 0., preferably 120 to 150 C.
• the inert diluent may be an aromatic or halogenated aromatic solvent.
• a small 3,526,672 Patented Sept. 1, 1970 amount of a polymerization inhibitor, such as p-tert-butylcatechol, is also conventionally used.
• EXAMPLE I A one liter stainless steel autoclave, fitted with a nitrogen inlet and outlet and a thermocouple well, was charged with 5 g. (2.6% by weight based on butadiene charged) of N-phenyl-2-naphthylamine, 0.3 g. of p-tert.-butylcatechol (polymerization inhibitor) and 50 ml. g., 34% by weight) o-dichlorobenzene (diluent). After being flushed with nitrogen to remove all residual air and sealed, the autoclave was cooled in a Dry Ice-acetone bath and charged with 191.7 g. of 1,3-butadiene. The charged autoclave was heated at 130l40 C. for 8 hours.
• the maximum internal pressure was 300 p.s.i., and, after 8 hours, dropped to 220 p.s.i. After 8 hours, the autoclave was left to cool to room temperature overnight, after which time, unreacted butadiene was vented from the autoclave. The liquid residue which remained was fractionated through a glass column (23 x 2 cm.) filled with glass helices. The yield of 4-vinylcyclohexene (B.P. 127-130 C.) was 85.2% (based on reacted butadiene).
• EXAMPLE II A one liter stainless steel autoclave, fitted with a nitrogen inlet and outlet and a thermocouple well, was charged with 10 g. (5.2% by weight) of di-2-naphthylaminc, 0.6 g. of p-tert.-buty1catechol, and 32.5 g. (17% by weight) of o-dichlorobenzene (diluent). After the autoclave was flushed with nitrogen to remove residual air and sealed, it was cooled in a Dry Ice-acetone bath, and charged with 193.4 g. of 1,3-butadiene. The charged autoclave was heated at 139-141" C.
• Metal acetylacetonates alone and in combination with either secondary aromatic amines or triphenylphosphine are also effective catalysts in producing high yields of 4- vinylcyclohexene (4-VC).
• Example No. Name percent Name percent hours C. p.s.i. 4-VC III 1 Pi eridine 2.6 Toluene 16. 6 8 135-140 270-420 11. 9 IV N- phenyl-lnaphthylami 5. 2 O-dichlorobenzene 13. 8 8 120-150 310-370 84 8 V Ferric actitylacetonaiienan 2 do 13. 8 8 138-141 220-410 85 4 N-pheny -1-naphthy am ne 6 I VI " ⁇ gerric acezyiacezona? 2 ⁇ 8 8 130 150 3304390 84 1 err e ace y ace ona e.
• Piperidine and diethanolamine belong to the class of secondary aliphatic amines which are claimed to be effective catalysts in this process in the prior art.
• Our experiments have shown that the yields of ii-vinylcyclohexene (4-VC) are much higher when the novel catalysts of this invention (secondary aromatic amines, triphenylphosphlne, and/or ferric acetylacetonate) are used.
• the process of dimerizing 1,3-butadiene to produce 4-vinylcyclohexene which comprises maintaining 1,3-butadiene in contact with a catalyst selected from the group consisting of (1) secondary aromatic amines; (2) fern'c acetylacetonate; (3) mixtures of (l) and (2); and (4) mixtures of (2) and triphenylphosphine.
• a catalyst selected from the group consisting of (1) secondary aromatic amines; (2) fern'c acetylacetonate; (3) mixtures of (l) and (2); and (4) mixtures of (2) and triphenylphosphine.
• reaction mixture is maintained in the presence of an inert diluent in a concentration of 0 to by weight (based on the weight of said butadiene).

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

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Citations (7)

• 1969
  • 1969-01-14 US US791182A patent/US3526672A/en not_active Expired - Lifetime
  • 1969-12-30 GB GB1290449D patent/GB1290449A/en not_active Expired

Patent Citations (7)

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