Effect of support hydrophobicity of halloysite‐based catalysts on the polyalphaolefin hydrofinishing performance

Abstract

Hydrogenation of polyalphaolefins (PAOs) is an industrial process catalyzed by supported precious metals. In this regard, halloysite (Hal) clay has been proven as an efficient support for the immobilization of Pd nanoparticles and development of high-performance catalysts under mild reaction condition. In this research, the effect of Hal hydrophobicity on the PAO hydrofinishing efficiency is studied. In this line, cetrimonium bromide (CTAB) was used for adjusting the hydrophobicity of halloysite surface. Three catalysts, Hal/Pd, Hal/Pd/CTAB, and Hal/CTAB/Pd, were fabricated by palladation of Hal, treating palladated Hal with CTAB and palladation of CTAB-treated Hal, respectively. The catalysts were characterized, and their activity for the hydrogenation of PAO was appraised. Moreover, a molecular simulation approach was employed to survey the effect of surface hydrophobicity of Hal on the alkene hydrogenation energy diagram and the steric maps of the main catalytic stages. Both experimental and computational studies approved that the presence of CTAB detracts the activity of the catalyst. Moreover, the order of introduction of Pd and CTAB affects the content of incorporated CTAB and Pd and Pd particle size, and the order of catalysts activity was as follows:

%VBur index and steric maps: from predictive catalysis to machine learning

“…With respect to COSMO radii, for Bondi radii no requirement exists for input manipulation to designate the hybridization states of atoms; thus, structures derived from theoretical or experimental methods can be directly employed without modification. Emphasize that ligand is used here because it is the easiest example, and also the pioneer, of using the V concept, but it is really extrapolable to any structure one can imagine, from metallic organic frameworks 147,148 to silicates, 31,149 clusters, 150,151 amino acids or enzymes, 14,152 to give some diametrically opposed examples. And take for instance, the %V Bur index of the ligand can lead to explain how pesticides trap free metals from the soil, 153 or unveil the complexation of trichlorosalicylic acid with metals to enhance the resulting complexes as antibacterial agents.…”

“…The scope of %V Bur parameter covers the whole range of reactions, including hydrogenation, 31,32 oxidation, [33][34][35] crosscoupling reactions, 36 polymerization, 29,37,38 among others.…”

“…As the method continues to advance, it has the potential to revolutionize the fields of chemistry and materials science, leading to new discoveries and advances in various areas. Despite the clear qualitative character of steric maps, 220,221 still currently to quantify, the %V Bur index must be used to quantify, 174,[222][223][224] or in combination, 31,219,225,226 preferentially because it covers both quantitative and qualitative aspects.…”

Free-Radical Photopolymerization for Curing Products for Refinish Coatings Market

“…This technique has already been implemented in many applications, such as wood finishing [ 21 ], biomedical engineering [ 22 ], dental materials [ 23 , 24 ] or adhesives [ 19 , 25 , 26 , 27 ], and more recently in the automotive refinish coatings market [ 20 , 28 , 29 ]. The applications of the coating are so extensive as to include even the keratin treatment of human hair, i.e., photoprotective coating of human hair [ 30 ], using its aqueous mixtures on a natural halloysite clay nanotube [ 31 , 32 , 33 ] that can be easily decorated [ 34 , 35 , 36 ].…”

Lubricant hydrogenation over a functionalized clay‐based Pd catalyst: A combined computational and experimental study

“…[41][42][43] However, in homology to chitosan, [44] the participation of a ligand covalently bonded to the HNT was not considered in some works, either by acid treatment to change the diameter of HNT lumen, [45] or changing the HNT hydrophobicity through non-covalent interactions of a surfactant. [40] Knowing the broad scope of reactions, where HNTs are involved, specifically into the synthesis of organic products, [46] ranging from oxidation reactions [47] to basically hydrogenations, [48] thanks to the high power of molecular hydrogen storage, [49] here we have characterized by experiments and density functional theory (DFT) calculations a HNT-based system, with a diamino ligand capable to trap Pd nanoparticles, in particular, the 1,3-diaminopropane (DAP). The catalytic centers have the catalytic power to hydrogenate polyalphaolefins (PAOs), which is one of the key steps in oil industry, [50,51] if not the most relevant.…”