Synthesis of Propylene Carbonate by Urea Alcoholysis—Recent Advances

Abstract

Organic carbonates are considered the chemicals of the future. In particular, propylene carbonate is widely used as a non-reactive solvent, plasticizer, fuel additive, and reagent, especially in the production of environmentally friendly polymers that are not harmful to human health. This paper reviews recent literature findings regarding the development of propylene carbonate synthetic methods starting from propane-1,2-diol and urea. The ammonia formed during the synthesis is recycled to obtain urea from carbon dioxide.

Exploring the Performance Improvement for CO2 Chemical Fixation in Zn/ZnMg-MOFs

“…The Zn 4 O and Zn 3 O clusters are bridged by carboxylate oxygens of L 6− , which is further extended and leads to a 3D framework structure of 1, as shown in Figure 1b. For the topology of 1, the Zn 3 O and Zn 4 O clusters can be considered as 4-connected nodes, while the L 6− ligands act as a sixconnected linker, and the Schlafli symbol of {4 12 •6 3 } was analyzed by TOPOS40, as shown in Figure 1c. Interestingly, the 3D framework exhibits two types of 1D channels, with dimensions of ∼7.6 × 8.7 and ∼5.6 × 7.0 Å 2 (taking the van der Waals radius into consideration) along the crystallographic b-axis, respectively (Figure S3).…”

“…However, it requires a multimeasure and multipronged approach . The reaction of CO 2 with epoxides to form cyclic carbonate is one of the most economical and promising methods to utilize CO 2 at present. , Cyclic carbonates, as a reaction intermediate for many organics, is widely used in pharmaceutical intermediates, organic synthesis, − and other fields. − Due to the structural rigidity and stability of CO 2 itself, most of the chemical transformations of CO 2 require high pressure and high reaction temperature . Therefore, effective catalysts are essential to chemical CO 2 fixation .…”

Efficient Propylene Carbonate Synthesis from Urea and Propylene Glycol over Calcium Oxide–Magnesium Oxide Catalysts

“…However, upon further increase, the PC yield dropped to 86% at the ratio of 5:1. This can be explained by the fact that a very high PG/urea ratio will lead to an extremely low urea concentration, which will trigger side reactions and result in the formation of undesired products [ 40 ]. As a result, the reaction rate will decrease, resulting in a low PC yield.…”

“…The stability of CaO–MgO was determined by consecutive reuse in the following manner: After completion of the first reaction of PC synthesis, the catalyst was recovered by centrifuge, washed with ethanol, dried in an oven at 60 °C for 6 h, and then reused. The catalyst was again reused by the same procedure two more times and then regenerated by calcining it at 700 °C for 5 h after drying according to the previously described procedure [ 40 , 41 ]. This regenerated catalyst was used for PC synthesis, and the recovered catalyst after completion of the reaction was reused again two more times, the results of which are shown in Figure 6 .…”