Disclosed herein are methods of producing alumina trihydrate crystals from an alumina trihydrate recovery process stream wherein an aqueous emulsion comprising a crystal growth modifier, which is at least one of an acyclic anhydride or an alkyl or alkenyl succinic anhydride, is added to the alumina trihydrate recovery process stream, wherein the aqueous emulsion is substantially free of mineral oils. The method provides a decrease in percentage of alumina trihydrate crystals having a volume average diameter of less than about 45 micrometers compared to the percentage of alumina trihydrate crystals produced in the absence of the crystal growth modifier. The process does not require the addition of a defoamer/anti-foam agent in order to control foam generated in the process.

A catalyst for a dehydrogenation reaction includes a carrier including Al.sub.2O.sub.3 having a theta () phase, an active metal supported on the carrier and including a noble metal, and an auxiliary metal supported on the carrier and different from the active metal.