More Like this

1. Brown Grease as a Precursor to Polyol Monomer for Polyurethane Synthesis

   https://doi.org/10.1002/slct.202503006  

   Ksor, Ykok B; Tennyson, Andrew G; Smith, Ashlyn D; Smith, Rhett C (September 2025, ChemistrySelect)

   Abstract The valorization of waste‐derived feedstocks for polymer synthesis represents a sustainable alternative to petroleum‐based materials. In this study, brown grease, a low‐value waste lipid source, is utilized as a precursor for polyol monomer synthesis via a two‐step functionalization process. Transesterification of brown grease with allyl alcohol generates allyl esters, which are subsequently modified via thiol‐ene click chemistry with 2‐mercaptoethanol to yield hydroxyl‐functionalized polyols (BG‐diol). The thiol‐ene reaction proceeds under mild UV‐initiated conditions, achieving high conversion efficiency (>90%) while preserving the structural integrity of the derived polyol.BG‐diolis further polymerized with 4,4′‐methylene diphenyl diisocyanate (MDI) through step‐growth polymerization to form brown grease‐derived polyurethane (BG‐PU). Comparative analysis ofBG‐PUwith polyurethane (PU) synthesized from purified oleic acid (OLA‐PU) demonstrates comparable molecular weight distributions (M_n = 14.4 kDa,M_w = 20.4 kDa forBG‐PU) and thermal properties (T_g = 24 °C,T_d,5%= 270 °C forBG‐PU). These results underscore the feasibility of brown grease as a cost‐effective and renewable alternative to plant oil‐based polyols, offering a pathway toward sustainable PU production while mitigating food security concerns. This approach exemplifies the potential of waste lipids in circular economy strategies for high‐performance polymer synthesis. 

   more » « less
2. As predicted and more: modulated channel occupation in YZn5+x

   https://doi.org/10.1107/S2052520623005292  

   Fredrickson, Rie T; Fredrickson, Daniel C (August 2023, Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials)

   Like many complex intermetallic phases, the crystal structures of REZn_5+xcompounds (RE = lanthanide or Group 3 element) based on the EuMg₅type have gradually unfolded. The original reports described a complex hexagonal structure with an unusual combination of tetrahedrally close-packed regions and open spaces, as well as observations of superstructure reflections. More recently, we reinvestigated the structure of YZn₅, reclassifying it as the EuMg_5+x-type compound YZn_5+x(x ≃ 0.2), in which disordered channels run alongcthrough the spaces formerly considered open. In addition, DFT-chemical pressure (DFT-CP) analysis of ordered models of YZn_5+xhighlighted paths for communication between neighboring channels setting the stage for superstructure formation. Herein, the experimental elucidation of this effect is presented with the synthesis and structure determination of a modulated form of YZn_5+x. By slow-cooling samples of YZn_5+xfrom the annealing temperature, crystals were obtained that exhibit satellite reflections with the modulation wavevectorq= {1\over 3}a*+ {1\over 3}b*+ 0.3041c*. Structure solution and refinement using a (3+1)D model in superspace groupP31c({1\over 3}\,\!{1\over 3}σ₃)00sreveals incommensurate order in the structure's channels. Here, two Zn sites associated with the channels are present, each with discontinuous atomic domains that are slanted in thex₃x₄plane. Their slanting corresponds to adjustments along thecaxis for the presence or absence of close neighbors along that axis, while the occupation patterns of neighboring channels are shifted by {1\over 3} of the modulation period. These features follow earlier predictions from CP analysis, highlighting how this approach can be used predictively in search of new phenomena. 

   more » « less
3. New Isoxazole‐Substituted Aryl Iodides: Metal‐Free Synthesis, Characterization and Catalytic Activity

   https://doi.org/10.1002/ejoc.202301191  

   Rimi; Uttam, Bhawna; Zhdankin, Viktor V.; Kumar, Ravi (February 2024, European Journal of Organic Chemistry)

   Abstract A series of new isoxazole‐substituted aryl iodides1 a–1 dhave been synthesized by DIB‐mediated [3+2] cycloaddition reaction of 2‐iodo‐1,3‐bis(prop‐2‐yn‐1‐yloxy) benzene (4) with corresponding benzaldehyde oximes5 a–5 d. Structure of the synthesized aryl iodides1were characterized by IR,¹H NMR,¹³C NMR and HRMS. The structure of1 awas also confirmed by single‐crystal X‐ray crystallography. Further, catalytic activity of iodoarenes1 a–1 dwas screened for the oxidation of hydroquinones and sulfides. On oxidation using aryl iodides1withm‐CPBA as terminal oxidant, hydroquinones afforded benzoquinones while sulfides gave corresponding sulfoxides in good to excellent yields. Iodoarene1 bshowed the best catalytic activity for the oxidation of sulfides and hydroquinones. Moreover, iodoarene1 b, was also utilized for α‐oxytosylation of acetophenones. 

   more » « less
4. Reactions of Unsymmetric Chiral Dialdehydes with Lysine: Regio‐ and Enantioselective Macrocyclization and Fluorescent Sensing

   https://doi.org/10.1002/ejoc.202401250  

   Mao, Yifan; Li, Yichen; Davis, Stephanie; Pu, Lin (February 2025, European Journal of Organic Chemistry)

   Abstract Three BINOL‐based unsymmetric chiral dialdehydes, (S)‐4, (S)‐5, and (S)‐6, each containing a salicylaldehyde moiety and anortho‐,meta‐ orpara‐substituted benzaldehyde unit, are synthesized and used to react with the enantiomers of an unsymmetric chiral diamine, lysine. These reactions represent the first examples of regioselective as well as enantioselective reactions of an unsymmetric chiral dialdehyde with an unsymmetric chiral diamine to generate unsymmetric chiral macrocycles. The addition of Zn²⁺can further enhance the selectivity for the macrocycle formation. Compounds (S)‐4and (S)‐5are found to exhibit chemoselective and enantioselective fluorescent recognition of lysine in the presence of Zn²⁺. 

   more » « less
5. Solid Decolorization: Dismantling of an Orange‐Red Zwitterionic Cocrystal by Multicomponent Milling

   https://doi.org/10.1002/adom.202400889  

   Ezekiel, Charles Izuchukwu; Ortiz‐de_León, Celymar; Reinheimer, Eric; MacGillivray, Leonard R (May 2024, Advanced Optical Materials)

   Abstract An application of multi‐component milling is described to achieve a decolorization by dismantling the orange‐red zwitterionic cocrystal (PDA)∙(APAP) (wherePDA= 2,4‐pyridinedicarboxylic acid,APAP= acetaminophen) usingn,n′‐BPE(BPE=trans‐1,2‐bis(n‐pyridylethylene and forn=n′ = 3 or 4). Each ofn,n′‐BPEforms a colorless hydrogen‐bonded cocrystal withPDA. 

   more » « less