The activity of a large number of binary-and ternary-oxide catalyst systems comprising dchydrating and dehydrogenating components has been tested for the conversion of ethanol to butadiene in the fixed bed.-Alumina-zinc oxide (60 : 40) was the best catalyst, and it gave a maximum of 55.8% process yield of ethanol to butadiene a t a temperature of 425" and ethanol feed rate of 1.875 ml./h./g. of catalyst.Other promising binary catalysts are alumina-magnesium oxide (80 : 20), alumina-ferric oxide or -chromium oxide (60 : 40) and zirconia-ferric oxide (40 : 60). These gave maximum process yields of 47.8, 37.7, 47.2 and 39.7% respectively under optimum conditions.Of 40 different ternary-oxide catalyst systems tried, only alumina-chromium oxide-ferric oxide (80 : 5 : 15) was appreciably active giving 35.7% process yield of butadiene under optimum conditions.In general, the ternary-are less active than the binary-oxide systems.
IntroductionIn Part I1 of this series were discussed the activities of various single oxide catalysts employed in the one-step catalytic conversion of ethanol to butadiene. It was concluded that only the oxides possessing both dehydrogenation and dehydration effects were comparatively active. In the light of the above conclusion, a thorough study on the activities of different binary and ternary oxide catalyst systems, comprising highly dehydrogenating and dehydrating components, has been carried out, and the present paper summarises the results obtained thereby.The published literature on the one-step catalytic conversion of ethanol to butadiene with binary and ternary oxide catalysts is extremely meagre. The reaction has now been studied with a large number of binary and ternary oxide catalyst systems (65 binary and 40 ternary), under widely varying operating conditions such as temperature, ethanol feed-rate, ethanol concentration in the feed, catalyst composition, etc.
An exhaustive investigation has been carried out on the one‐step catalytic conversion of ethanol to butadiene in the presence of a large number of single‐oxide catalyst systems.
The oxides of aluminium, magnesium, iron (III), zirconium and thorium, prepared by calcining the precipitate obtained on addition of aqueous ammonia or ammonium carbonate to a solution of the appropriate nitrate, had good catalytic activity, the process yield of butadiene from ethanol being 24.0, 27.4, 29.8, 35.5 and 31.1%, respectively, under optimum conditions, which were: temperature 400–500°; ethanol feed rate 1.256–1.875 ml./h./g. of catalyst.
The process yield of butadiene decreased with the water content of the feed.
Bulk polymerization of N-Vinylcarbazole (NVC) has been carried out using vanadium pentoxide as the contact catalyst. The rate of polymerization has been found to depend upon catalyst to monomer ratio. A cationic mechanism has been suggested and the role of Vz05 surface in the polymerization has been tentatively analyzed. The x-acid characteristics of V5Q ion is believed to be involved in initiating the polymerization. The effect of a number of additives on the polymerization rate has been studied, which endorses the cationic mechanism. The catalytic efficiency of a number of metal vanadates for the polymerization of NVC has also been studied. A fairly good correlation between the activity and electronegativity of the metallic moiety has been established.
ZUSAMMENFASSUNG:I n Gegenwart von Vanadiumpentoxid als heterogenem Katalysator wurde N-Vinylcarbazol (NVC) in Substanz polymerisiert. Die Polymerisationsgeschwindigkeit hingt vom Verhiiltnis des Katalysators zum Monomeren ab. Es wurde ein kationischer Reaktionsmechanismus vorgeschlagen, und es wurde versucht, die Rolle der VaOs-Oberflache bei der Polymerisation aufzuklaren. Es wird vermutet, daB die rr-Saureeigenschaft des V5Q-Ions bei der Initiierung der Polymerisation miteinbezogen werden muB.Die Wirkung einer Anzahl von Zusatzen auf die Polymerisationsgeschwindigkeit wurde untersucht ; das Ergebnis bekriiftigt die Annahme eines kationischen Verlaufs.Es wurde auch die katalytische Wirksamkeit einer Anzahl von Metallvanadaten bei der Polymerisation von NVC untersucht. Es ergab sich eine hinreichend gute Beziehung zwischen der katalytischen Wirksamkeit und dem elektronegativen Charakter des metallischen Bestandteils.
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