Raman studies of aldol condensation reactions on sodium-hydroxide-treated silica gel

Thesis/Dissertation · Mon Jan 01 04:00:00 EST 1979

OSTI ID:6455699

Klaassen, A W

Raman spectroscopy of acetaldehyde adsorbed on NaOH-treated silica gel at room temperature and 300 mm Hg acetaldehyde vapor pressure showed the presence of 6-hydroxy-2,4-dimethyl-1,3-dioxane, which decomposed at lower pressures, leaving chemisorbed acetaldol as the dominant surface species. At elevated temperatures, there were Raman bands of crotonaldehyde produced by the dehydration of adsorbed species. Spectroscopic evidence was obtained for the reaction of crotonaldehyde with adsorbed acetaldol and with adsorbed acetaldehyde, the latter reaction resulting in catalyst deactivation. Raman bands of acetaldehyde on untreated silica gel were assigned to adsorbed paraldehyde and indicated an acid-catalyzed reaction. Pyridine adsorption on NaOH-treated silica reduced the number of surface hydroxyl groups and the amount of physisorbed acetaldehyde, but did not affect the rate of aldol condensation. Raman spectroscopy of cumene adsorbed on alumina, silica-alumina, and four cation-exchanged zeolites indicated the vibrations most strongly affected by cumene interaction with these cracking catalysts.

• OSTI ID: 6455699
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201 -- Chemical & Physicochemical Properties
400301* -- Organic Chemistry-- Chemical & Physicochemical Properties-- (-1987)
ACETALDEHYDE
ADSORBENTS
ADSORPTION
ALDEHYDES
AROMATICS
AZINES
CATALYTIC EFFECTS
CHEMICAL REACTION YIELD
CHEMICAL REACTIONS
CUMENE
DATA
EXPERIMENTAL DATA
HETEROCYCLIC COMPOUNDS
HYDROCARBONS
INFORMATION
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PYRIDINES
RAMAN SPECTRA
SILICA GEL
SORPTION
SPECTRA
SURFACE TREATMENTS
YIELDS