We survey existing data for refrigerant blends containing halogenated olefins (hydrofluoroolefins (HFO), hydrochlorofluoroolefins (HCFO) and hydrochloroolefins (HCO)) in the open literature. The data are primarily taken from the NIST SOURCE database and are presented in graphical form to demonstrate the relative coverage of the data. The primary conclusion is that blends containing halogenated olefins remain only sparsely measured in experiments, and some classes of data (e.g., speed-of-sound data) are particularly sparse for blends containing halogenated olefins. The second part of this study compares the thermodynamic models in NIST REFPROP against the experimental datasets and identifies systems (of which there are many) where refitting of the thermodynamic model is required.
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http://dx.doi.org/10.1021/acs.jced.1c00192 | DOI Listing |
Chemistry
January 2025
Southwest University, Key Laboratory of Applied Chemistry of Chongqing Municipality, School of Chemistry and Chemical Engineering, 400715, Chongqing, CHINA.
A visible-light-mediated strategy is reported for the direct synthesis of polychlorinated vicinal diaryl alkanes from aryl alkenes and chloroform. In this approach, two haloalkyl radicals generated from chloroform via halogen atom transfer (XAT) and direct single electron transfer (SET) within the same photoredox catalysis cycle enable the 1,4-dichloromethyldimerization of alkenes. Besides chloroform, this strategy is applicable to carbon tetrachloride, bromotrichloromethane, and α-bromo carboxylic esters, yielding corresponding 1,4-disubstituted vicinal diaryl alkanes.
View Article and Find Full Text PDFJ Am Acad Orthop Surg
January 2025
From the UC Davis Department of Orthopaedic Surgery, Sacramento, CA.
Dilute povidone-iodine (polyvinylpyrrolidone iodine [PVP-I]) irrigation in spine surgery and total joint arthroplasty has seen a rapid and substantial increase in its use during the past decade. Yet, most surgeons do not know the chemistry and biochemistry that explain its efficacy in preventing infections. PVP-I forms a complex with molecular iodine (I2), facilitating the delivery of I2 to the membrane of the infectious organism.
View Article and Find Full Text PDFBeilstein J Org Chem
December 2024
Department of Chemical and Geological Sciences, University of Cagliari, S.S. 554, bivio per Sestu, 09042 Monserrato (CA), Italy.
The rising popularity of bioconjugate therapeutics has led to growing interest in late-stage functionalization (LSF) of peptide scaffolds. α,β-Unsaturated amino acids like dehydroalanine (Dha) derivatives have emerged as particularly useful structures, as the electron-deficient olefin moiety can engage in late-stage functionalization reactions, like a Giese-type reaction. Cheap and widely available building blocks like organohalides can be converted into alkyl radicals by means of photoinduced silane-mediated halogen-atom transfer (XAT) to offer a mild and straightforward methodology of alkylation.
View Article and Find Full Text PDFOrg Lett
December 2024
Key Laboratory of Bio-Based Material Science and Technology, Ministry of Education, College of Material Science and Engineering, Northeast Forestry University, Harbin 150040, People's Republic of China.
A visible-light-induced method for the hydrodichloromethylation of unactivated alkenes using chloroform (CHCl) was developed, employing pyridine·BH as the halogen atom transfer (XAT) reagent. The strategy showed a broad functional group tolerance, and 29 examples of unactivated alkenes, including complex natural products or drug derivatives, have been established with good yields. Mechanistic studies indicated that CHCl serves as both the source of a dichloromethyl radical and a hydrogen atom transfer (HAT) reagent, and the borane short-chain reaction process was involved in this system.
View Article and Find Full Text PDFOrg Lett
December 2024
College of Chemistry, Zhengzhou University, Zhengzhou 450001, P. R. China.
NHC boryl radical mediated halogen atom transfer (XAT) is useful in organic synthesis. Yet, most of the reaction ends only with reducing the halogen to hydrogen, that is, the C-X to C-H. This is especially dominant for electron-deficient alkyl halides, where the formed electrophilic radical reacts rapidly with NHC boranes.
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