Use of Phased Array Ultrasonic Testing For Sizing of Hydrogen Blisters In LPG Wash Water Vessel In INDMAX Unit

Equipments operating in sour environment containing H2S are prone to deterioration by wet H2S damage mechanism. INDMAX unit (patented FCCU) produces LPG which contains H2S, cyanide as impurities. To remove these impurities LPG is treated with caustic wash and subsequently water wash in series operation. Due to presence of wet H2S environment in the water wash vessel, nascent hydrogen is produced which diffuses in to the wall of the vessel. Due to presence of laminations in the CS shell these hydrogen atoms combined to form hydrogen molecule which exerts severe internal pressure greater than the yield strength of the CS wall inside the laminations resulting in formation of hydrogen blister. This paper describes the use of phased array UT (PAUT) technique for detection of lamination and sizing of hydrogen blisters in the LPG wash water vessel. Fitness for purpose study was carried out for safe operation of this vessel

Multimorbidity and its social determinants among older people in southern provinces, Vietnam

Background: Developing countries are poorly equipped for health issues related to ageing populations making multimorbidity challenging. As in Vietnam the focus tends to be on single conditions. Hence little is known about burden of multimorbidity. This study aimed to examine the prevalence and the determinants of multimorbidity among older people in Southern Vietnam. Methods: A cross-sectional study was conducted in two provinces of Southern Vietnam with a sample of 2400 people aged 60 years and older. The presence of chronic disease was ascertained by medical examination done by physicians at commune health stations. Information on social and demographic factors was collected using structured questionnaire. Univariate and multivariable logistic regression analyses were used to examine the factors associated with multimorbidity. Results: Nearly 40 % of older people had multimorbidity. Currently not working, and healthcare utilisation were associated with higher prevalence of multimorbidity. Living in urban areas and being literate were associated with lower prevalence of multimorbidity. Conclusion: The study found a high burden of multimorbidity among illiterate, especially those living in rural areas. This highlights the need for targeted community based programs aimed at reducing the burden of chronic disease

Rhodium Catalyzed Stereoselective Mono-alkenylation of Aryl sp2 C-H Bond via C-N Bond Cleavage: N-allylbenzimidazole as Strategic Alkenylating Agent

A Rh-catalyzed C(sp2)-H alkenylation has been achieved by taking N-allylbenzimidazole as an allylamine congener. This distinctive transformation has been observed for the first time which is attributed to the rigid benzimidazole unit. Lewis acid assisted cleavage of C(sp3)-N bond by coordinating to the N3 of N-allylbenzimidazole has been established. Thus, herein we have demonstrated an unprecedented protocol of domino C-N bond cleavage followed by aryl C(sp2)-H alkenylation. Further, detailed mechanistic studies, control experiments have been conducted to understand the mechanism. The rhodacycle-intermediates involved in the reaction have been isolated and characterized through NMR, HRMS, and single crystal X-ray

Overcoming the Challenges towards Selective C(6)-H Alkylation of 2-Pyridone with Maleimide through Mn(I)-Catalyst: Migration of directing group through cleavage of C-N bond for the formation of all-carbon quaternary carbon center

An earth-abundant and inexpensive Mn(I)-catalyzed alkylation of 2-pyridone with maleimide has been reported for the first time, in contrast to previously reported Diels-alder product. The directing group was easily removed after functionalization. Notably, unexpected migration of pyridine ring has been discovered in presence of acetic acid, which also provides unique class of compounds with three different N-heterocycles with an all-carbon quaternary carbon center. Furthermore, single crystal X-ray and HRMS revealed a five-membered manganacycle intermediate. This methodology tolerates a wide variety of functional groups delivering the alkylated products in moderate to excellent yields

Transition Metal-catalyzed C-H /C-C Activation and Coupling with 1, 3-diyne

This review focuses on providing a broad overview of the recent developments in the field of transition metal-catalyzed C-H bond activation and coupling with 1,3-diyne for assembling alkynylated heterocycles and bis-heterocycles. In recent years the use of 2π-unsaturated units as coupling partners for the synthesis of heterocycles through C-H bond activation and an-nulation sequence has received immense attention. Among the unsaturated units employed for assembling heterocycles, the use of 1,3-diynes has garnered significant attention due to its ability in rendering the straightforward bis-heterocycles. Earlier methods employed to assemble bis-heterocycle include the use of preformed and pre-functionalized heterocycles via transi-tion metal-catalyzed coupling reactions. The expensive pre-functionalized halo-heterocycles and sensitive & expensive heterocyclic metal reagents limit its use. However, the transition metal-catalyzed C-H activation obviates the need for expensive heterocyclic metal reagents and pre-functionalized halo-heterocycles. The C-H bond activation strategy makes use of C-H bonds as functional groups for effecting the transformation. This renders the overall synthetic sequence both step and costs economic. Hence, this strategy of C-H activation and subsequent reaction with 1,3-diyne is useful for the larger-scale synthesis of chemicals in the pharmaceutical industry. Despite these advances, there is still the possibility of exploration of earth-abundant, and cost-effective first-row transition metals (Ni, Cu, Mn. Fe, etc.) for the synthesis of bis-heterocycles. Moreover, the Cp* ligand free, simple metal salt mediated synthesis of bis-heterocycles is also less explored. Thus, more exploration of reaction conditions for the Cp* free synthesis of bis-heterocycles is called for. We hope this review will inspire scientists to explore the unexplored domains

Rhodium-Catalyzed Selective C(sp2)-H Activation/Annulation of tert- butyl benzoyloxycarbamates with 1,3-Diynes: A one Step Access to Alkynylated Isocoumarins and Bis-Isocoumarins

We report here a Rh(III) catalysed regio- and stereo-selective synthesis of alkynylated and bis-iso- coumarin from 1,3-dialkyne. Exclusive one-pot formation of 3,3-bis-isocoumarin isomer has been achieved by elim- inating several other possibilities. This is the first example of transition metal catalyzed synthesis of alkynylated and bis-isocoumarin scaffold. The protocol is compatible with a wide range of functional groups affording good to excel- lent yields. Several mechanistic investigations including deuterium labeling experiment and kinetic isotope effect study have been carried out

Palladium-Catalyzed C-C Bond Activation and Regioselective Alkenyla-tion between Cyclopropanol and 1,3-Diyne: One-Step Synthesis of Di-verse Conjugated Enynes

We report here the first example of the use of 1,3-dialkynes in C-C bond activation with any metal. The regio- and stereo-selective synthesis of 1,3-enynes from 1,3-diynes is demonstrated by the palladium-catalyzed C-C bond activation of cyclo-propanol. Exclusive formation of mono-alkenylated adduct was achieved by eliminating the possibility of di-functionalization with high regio- and stereo-selectivity. Indeed, this protocol worked very well with electronically and sterically diverse substrates. Several studies, including deuterium labeling experiments and intermolecular competitive experiments, were carried out to understand the mechanistic details. The atomic-level mechanism followed in the catalytic process was also validated using DFT calculations, and the rate-controlling states in the catalytic cycle were identified. Further, preliminary mechanistic investigations with radical scavengers revealed non-involvement of the radical pathway for this transformation

Cobalt catalyzed decarbonylative ipso-C-C bond functionalization: Synthesis of Indole C-3 functionalized acyloins using 1,2-diketone

Selective functionalization of indole C3-C bond with aromatic/heteroaromatic 1,2-diketones has been uncovered for the first time. Earth crust abundant first-row transition metal cobalt catalyst has been demonstrated as an effective catalyst for this unusual transformation. Furthermore, the use of easily available weakly coordinating groups such as ketone and ester was found to be effective. The key feature of this methodology is the in-situ generation of water from hexafluoro-2-propanol and the removal of the pivaloyl/ester group in a decarbonylative manner at a lower temperature. In addition, photophysical studies show the potential utility of indole (C3)-acyloin and indolo-fused carbazole, in photovoltaic and optoelectronic application