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Green Materials for Waterborne Polyurethanes
Published in Ram K. Gupta, Ajay Kumar Mishra, Eco-Friendly Waterborne Polyurethanes, 2022
Felipe M. de Souza, Prashant Kote, Ram K. Gupta
Hydroformylation involves the addition of CO and H2 to an alkene to form an aldehyde. The aldehydes produced by hydroformylation are normally reduced to alcohol via hydrogenation, which is a reaction with hydrogen under pressure and catalysts such as Pt or Raney Ni. Hydroformylation is usually carried out in the presence of Rh or Co carbonyls as catalysts. Rh catalysts are very efficient, avoid oligomerization, and deliver almost 100% conversions; however, they are not cost-effective. On the other hand, hydroformylation with Co allows some oligomerization, likely due to transesterification at higher temperatures. Petrovic et al. made an interesting study on the property of several polyols based on soybean that was synthesized through the hydroformylation/reduction method [15]. This approach presents some advantages, such as the introduction of primary hydroxyl groups, which are more reactive toward isocyanate and the high conversion of aldehydes into hydroxyl groups, leading to a higher functionality of the polyols. When targeting for WPU, a high functionality may not be desired in the early stages of WPU synthesis, since it may lead to crosslinking yielding polymers that swell in solution instead of dispersing. It is possible to control the functionality by partially blocking the hydroxyl groups by performing esterification.
Synthesis Gas Chemistry
Published in Saeed Sahebdelfar, Maryam Takht Ravanchi, Ashok Kumar Nadda, 1 Chemistry, 2022
Saeed Sahebdelfar, Maryam Takht Ravanchi, Ashok Kumar Nadda
Hydroformylation is one of the most important applications of homogeneous catalysis in chemical industry. The typical catalyst is a transition metal complex with the general formula HM(CO)xLy (M = central atom of transition metals; L = ligands, x + y = 3, 4) with the M as central atom enables the formation of metal-carbonyl hybrid optionally modified by the ligand L (Cornils, 2018). Thus, replacing some of the CO ligands with other substituent such as phosphine ligands gives the so-called “modified” catalysts.
Porous Polymer for Heterogeneous Catalysis
Published in Inamuddin, Mohd Imran Ahamed, Rajender Boddula, Porous Polymer Science and Applications, 2022
Vivek Mishra, Simran Aggarwal, Shubham Pandey
Hydroformylation is a process for the synthesis of aldehydes and was developed in the 1930s by Roelen.70 In industries, hydroformylation was done by using homogeneous ligand-modified rhodium catalyst. However, heterogeneous catalysts have many advantages over a homogeneous catalyst such as easy recyclability, separation, etc. Therefore, Jia et al.71 synthesized a porous organic ligand (POL) loaded with Rh for the hydroformylation of internal and terminal olefins. They took divinyl-functionalized bisphosphoramidite (vBPa) and tris(4-vinylphenyl)phosphine (3vPPh3) as the comonomers for the synthesis of the POL-BPa&PPh3. vBPa was prepared in five steps. Initially, 2,2′-biphenol was reacted with bromine to give a brominated product which was reacted with acetyl chloride to give a diacetylated product. Then, the diacetylated product was reacted with potassium ethenyltrifluoroborate via a Pd-catalyzed Suzuki–Miyaura coupling reaction to give a product which was further hydrolyzed in a basic medium to give divinyl-functionalized biphenol. The resulting biphenol reacted with chlorodipyrolyphosphine in Et3N to give the comonomer vBPa. The other comonomer 3vPPh3 was synthesized by the reaction of (4-vinylphenyl)-magnesium bromide with PCl3. Copolymerization of vBPa and 3vPPh3 initiated by AIBN in THF resulted in the formation of POL-BPa&PPh3 which was reacted with Rh(acac)(CO)2 in THF to produce the desired Rh-loaded porous organic ligand (Rh/POL-BPa&PPh3) (Scheme 6.25).
Carbon capture and utilization technologies: a literature review and recent advances
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2019
Francisco M. Baena-Moreno, Mónica Rodríguez-Galán, Fernando Vega, Bernabé Alonso-Fariñas, Luis F. Vilches Arenas, Benito Navarrete
Hydroformylation is an industrial process of great importance in the manufacturing of aldehydes, obtained from olefins and syngas. This process involves the addition of CO and H2 to a carbon-carbon double bond, forming the aldehyde that contains a number of carbons greater than the starting olefin. Hydroformylation can be carried out by both homogeneous and heterogeneous catalysis, the latter being easy to recycle (Bektesevic et al. 2006). Most investigations on the hydroformylation of olefins or alkenes in scCO2 have been carried out in homogeneous catalytic systems, where the solvent is used to recover the catalyst after the reaction, what involves a great effort and a significant expense when traditional solvents are used. The results obtained with high molecular weight olefins have been quite satisfactory (85% yield) since these cannot be hydroformylated in aqueous bases with rhodium catalyst due to their low solubility in water (Aresta 2010; Bektesevic et al. 2006; Marriott, Jessop, and Barnes 2014).
Understanding oxidative addition in organometallics: a closer look
Published in Journal of Coordination Chemistry, 2022
Nabakrushna Behera, Sipun Sethi
Kinetically controlled carbonylation of alkenes in the presence of hydrogen and an organometallic catalyst is known as the hydroformylation reaction. It is one of the largest homogeneous catalytic processes which produce aldehyde as the major product. This process, generally, entails the net addition of a formyl group (CHO) as well as an H-atom to a carbon-carbon double bond (Scheme 20). Since its discovery by Otto Roelen in 1938 [52], it has come across different developmental processes with an aim to maximize the product yield.