Recent Advances in Selective Photo-Epoxidation of Propylene: A Review

Abstract

The epoxidation of propylene to produce propylene oxide (PO) has a vital role in the industrial production of several commercial compounds and the synthesis of numerous intermediates, fine chemicals, and pharmaceuticals. However, the current PO production processes pose significant problems regarding the environment and economy. The direct photo-epoxidation of propylene using molecular oxygen (an ideal oxidant with active oxygen of 100 wt %) under light irradiation is a promising technology to produce PO. This process offers numerous advantages, including the use of simple technologies, low-cost methods, and environmental friendliness. Many efforts have focused on the design of new photocatalyst systems, optimizing the conditions for a photocatalytic reaction, and elucidating the mechanisms of photo-epoxidation. This review is expected to serve as a comprehensive background, providing researchers with insight into the recent developments regarding the direct photo-epoxidation of propylene.

Normal-Weight Obesity Is Associated with Increased Cardiometabolic Risk in Young Adults

“…Excessive body fat increases the risk of other non-communicable diseases (NCD), such as cardiovascular disease (CVD), chronic respiratory disease, metabolic disorders, and certain types of malignant neoplasms [1,2]. Disturbances in adipose tissue function may induce alterations in adipose tissue metabolism (i.e., lipid metabolism/lipolysis) and the storage capacity of dietary lipid in adipose tissue.…”

“…The World Health Organization (WHO) defines obesity as excessive body fat accumulation, which is associated with several risks to health [1]. The body mass index (BMI), is used as a surrogate marker for body fat and for classifying obesity, is positively associated with risk factors for cardiovascular and metabolic diseases when BMI is above 18.5 kg/m 2 [4].…”

Insight into the Effect of Copper Substitution on the Catalytic Performance of LaCoO3-Based Catalysts for Direct Epoxidation of Propylene with Molecular Oxygen

“…By contrast, direct epoxidation of propylene by molecular oxygen (DEP) remains a desirable and environment-friendly process for its high atom utilization efficiency . Therefore, considerable effort has been put into the study of the DEP process by researchers .…”

Advances in Designing Au Nanoparticles for Catalytic Epoxidation of Propylene with H2 and O2

“…However, these routes produce a significant amount of coproducts (styrene, ter-butyl alcohol, and dimethyl benzyl alcohol), which heavily depend on market demand. Other processes, such as direction oxidation (catalytic epoxidation and photocatalytic epoxidation), electrochemical, and biochemical processes, also receive considerable attention [1,2,[6][7][8][9][10][11][12][13]. It is noted that an excellent turnover frequency (TOF, 12 s −1 ) could be observed via the biological process [6].…”

“…Hayashi et al firstly reported that using a mixture of O 2 and H 2 with Au nanoparticles (2-5 nm) dispersed in titanium dioxide (TiO 2 ) could effectively epoxidize propylene to yield PO with favorable results (PO selectivity > 90%, propylene conversion = 1%-2%) [14]. The proposed reaction pathway for the epoxidation of propylene has two steps: (1) hydrogen peroxide is firstly produced on the Au surfaces, and then (2) hydrogen peroxide is transported close to (−OOH) on the tetrahedral-coordinated Ti 4+ centers to react with propylene ( Figure 2) [15][16][17]. Since the proposal of the aforementioned pathway, extensive research has been carried out with regard to designing novel supported Au catalysts (e.g., Au/Ti-contained catalysts) for driven epoxidation.…”