5631-89-0

Basic information

• Product Name: 4,6-Dimethyl-3,5-heptadien-2-one
• Synonyms: 4,6-Dimethyl-3,5-heptadien-2-one
• CAS NO: 5631-89-0
• Molecular Formula: C₉H₁₄O
• Molecular Weight: 138.21
• Mol File: 5631-89-0.mol
• Article Data: 1

Chemical Properties

• Appearance: /
• CAS DataBase Reference: 4,6-Dimethyl-3,5-heptadien-2-one(CAS DataBase Reference)
• NIST Chemistry Reference: 4,6-Dimethyl-3,5-heptadien-2-one(5631-89-0)
• EPA Substance Registry System: 4,6-Dimethyl-3,5-heptadien-2-one(5631-89-0)

Safety Data

• Hazardous Substances Data: 5631-89-0(Hazardous Substances Data)

Upstream product

• 83521-56-6 3-acetyl-4,6,6-trimethyl-5,6-dihydro-2-pyrone 
• 623-11-0 1-methyl-4-nitrosobenzene 
• 67-64-1 acetone 

Relevant articles and documents

Condensation and esterification reactions of alkanals, alkanones, and alkanols on TiO2: Elementary steps, site requirements, and synergistic effects of bifunctional strategies

Rates and selectivity of TiO2-catalyzed condensation of C3 oxygenates (propanal, acetone) are limited by ubiquitous effects of side reactions, deactivation, and thermodynamic bottlenecks. H2 together with a Cu function, present as physical mixtures with TiO2, circumvents such hurdles by scavenging unsaturated intermediates. They also render alkanols and alkanals/alkanones equivalent as reactants through rapid interconversion, while allowing esterification turnovers by dehydrogenating unstable hemiacetals. Oxygenates form molecules with new C-C and C-O bonds and fewer O-atoms at nearly complete conversions with stable rates and selectivities. Kinetic, isotopic, and theoretical methods showed that rates are limited by α-C-H cleavage from carbonyl reactants to form enolate intermediates, which undergo C-C coupling with another carbonyl species to form α,β-unsaturated oxygenates or with alkanols to form hemiacetals with new C-O bonds, via an intervening H-shift that forms alkoxide-alkanal pairs. Titrations with 2,6-di-tert-butylpyridine, pyridine, CO2, and propanoic acid during catalysis showed that Lewis acid-base site pairs of moderate strength mediate enolate formation steps via concerted interactions with the α-H atom and the enolate moiety at transition states. The resulting site-counts allow rigorous comparisons between theory and experiments and among catalysts on the basis of turnover rates and activation free energies. Theoretical treatments give barriers, kinetic isotope effects, and esterification/condensation ratios in excellent agreement with experiments and confirm the strong effects of reactant substituents at the α-C-atom and of surface structure on reactivity. Surfaces with Ti-O-Ti sites exhibiting intermediate acid-base strength and Ti-O distances, prevalent on anatase but not rutile TiO2, are required for facile α-C-H activation in reactants and reprotonation of the adsorbed intermediates that mediate condensation and esterification turnovers.