Hydrogenation of Styrene Oxide to 2-Phenyl Ethanol over Polyurea Microencapsulated Mono- and Bimetallic Nanocatalysts: Activity, Selectivity, and Kinetic Modeling

Abstract

Styrene oxide is an important precursor to prepare 2-phenyl ethanol (2-PEA) of high quality for its use as a fragrance chemical. Styrene oxide was selectively hydrogenated to 2-PEA with polyurea-microencapsulated (EnCat) Pd, Pd–Rh and Pd–Cu nanocatalysts with methanol as solvent and NaOH as promoter. The catalysts were fully characterized to understand their activity, selectivity, and stability. Pd–Cu EnCat was used for further studies. Complete conversion of styrene oxide with 92% selectivity to 2-PEA was obtained over Pd–Cu EnCat at 333 K and 607.8 kPa. Effects of various parameters were studied to understand the product profile. A bifunctional Langmuir-Hinshelwood-Hougen-Watson (LHHW) mechanistic model was proposed. The kinetics of reaction was established and tested against experimental data. The results are new and provide a green and cost-effective process for the synthesis of 2-PEA.

Selective hydrogenation of 3,4‐dimethoxybenzophenone in liquid phase over Pd/C catalyst in a slurry reactor

“…[23][24][25][26] Assuming S 1 and S 2 as two different types of sites on the catalyst surface for the adsorption of 3,4-DMBH and hydrogen, the following model is developed. Langmuir-Hinshelwood-Hougen-Watson (LHHW) mechanism was used to analyze the initial rate data.…”

“…Langmuir-Hinshelwood-Hougen-Watson (LHHW) mechanism was used to analyze the initial rate data. [23][24][25][26] Assuming S 1 and S 2 as two different types of sites on the catalyst surface for the adsorption of 3,4-DMBH and hydrogen, the following model is developed. Adsorption of 3,4-DMBH (A) on vacant site (S 1 ) is given by…”

Self‐Assembly of Lotus‐Type Holes Two‐Dimensional NiO Nanosheets and Its Efficient Catalytic Property for Styrene Epoxidation

“…Styrene oxide can be synthesized into many intermediates of pharmaceuticals and fine chemicals through selective ring opening and functional group conversion, and are widely used in organic synthesis, pharmaceutical chemicals, flavors and fragrances and other fields . Styrene epoxidation is the main method for the preparation of styrene oxide directly.…”

Cucurbit[6]uril-Stabilized Palladium Nanoparticles as a Highly Active Catalyst for Chemoselective Hydrogenation of Various Reducible Groups in Aqueous Media

“…To address this issue different basic inorganic supports like MgO,, hydrotalcite, alumina and silica have been used with fair success. Besides these, nitrogen‐rich organic polymers were also successfully employed as a support for palladium catalyzed hydrogenation of various substrates . However, all these systems are designed to do mostly substrate specific hydrogenation with little or no variation in substrate scope, except for very limited citations where a single support but with some variation in the catalyst preparation was able to handle a variety of substrates ,.…”

“…However, all these systems are designed to do mostly substrate specific hydrogenation with little or no variation in substrate scope, except for very limited citations where a single support but with some variation in the catalyst preparation was able to handle a variety of substrates ,. Further, there are very few reports where water has been used as reaction medium using specially designed nitrogen‐containing support modified with a long‐chain alkyl group (dodecane) for Pd‐catalyzed chemoselective (terminal) hydrogenation of alkenes …”