Quantum chemical study on gas phase pyrolysis of p-isopropenylphenol

In the pyrolysis of Sphagnum moss species, p-isopropenylphenol (p-IPP) is a major product which has been considered in this density functional theory based computational study for its conversion to various products such as benzene, phenol, 4-propenylphenol, indan-5-ol, 4-propylcyclohexanone, 4-cyclopropylphenol, etc. In order to achieve these products, eight different reaction schemes are performed using B3LYP/6–311 + g (d,p) level of theory. Further, thermodynamic properties such as reaction free energies and reaction enthalpies associated with these eight reaction schemes are developed in the temperature range of 298–898 K. The reaction schemes that include partial hydrogenation of the aromatic carbon followed by elimination of functional groups are found to demand low activation energy. The production of benzene from p-IPP with isopropenylbenzene as an intermediate product requiring only 19.83 kcal/mol of activation energy is the rate limiting reaction step. Indan-5-ol produced from p-IPP is validated with the literature results and found excellent agreement between two results. Furthermore, the temperature is found to have phenomenal effect in each reaction scheme

Production of toluene by decomposition of 2-hydroxy-6-methylbenzaldehyde: a DFT study

The fast pyrolysis of lignocellulosic biomass produces raw bio-oil that comprises of several oxygenated organic compounds which are disadvantageous and lower the quality of bio-oil as a fuel. In this numerical study, 2-hydroxy-6-methylbenzaldehyde (HMB) component, one such oxygenated compound which represents aromatic aldehyde category of bio-oil, is considered as model compound for its decomposition within the framework of density functional theory. The bond dissociation analysis of HMB component suggests that the dehydrogenation of methyl group is the least energy demanding amongst all nine possible bond scissions. Further, eight reaction pathways are investigated for the conversion of HMB into toluene as end product along with the analyses of their corresponding potential energy surfaces. Briefly, results indicate that the optimum reaction progress for the production of toluene from HMB requires an activation energy of 12.26 kcal/mol. It is further observed that the production of toluene from HMB includes m-cresol as an intermediate instead of 2-formyltoulene; and, the production of 2-hydroxybenzaldehyde is not favourable. Furthermore, the thermochemistry analyses for the production of toluene using optimum reaction pathway and for the production of 2-hydroxybenzaldehyde using reaction pathway 9 are performed over a wide range of temperature, i. e., 473–873 K at an interval of 100 K. The thermochemistry also suggests higher favourability for the production of toluene compared to the production of 2-hydroxybenzaldehdye by decomposing HMB

Foot morphology and its relationship to arch height index in asymptomatic adults versus adults presenting with foot pain (nontraumatic)

Background: The uniqueness of the human foot, in performing various functions, is intricately associated with different morphological parameters, and arch height index (AHI) is an important parameter for the same. The measurement of AHI has putative clinical implications in correcting the underlying causative factors, which contribute to foot pain. This study was an attempt to investigate these parameters as a correlation among asymptomatic versus patients complaining of foot pain (due to nontraumatic causes). Methodology: One hundred asymptomatic and 50 symptomatic adults were engaged in the study after taking prior consent. Various measurements (such as foot length, truncated foot length, foot breadth, arch height – [AH], and AHI) were taken in a standing position. In this study values of foot length, truncated foot length, foot breadth, AH and AHI were compared amongst the two groups . Comparison was done with earlier studies. Results: The difference in AH and AHI (P < 0.05) among the asymptomatic versus the foot pain patients, was significant. There was a considerable difference in body weight and Body Mass Index (BMI) affecting AH and AHI. AHI in the case of the symptomatic foot pain adults was 0.18 in both feet, with a standard deviation (SD) of 0.07. Conclusion: The AHI has been considered an essential parameter in defining and identifying the potential structural factors that predispose an individual to injuries of the foot. Our results indicate that the mean AHI in the case of foot pain adults (nontraumatic) was 0.18 in both feet, with an SD of 0.07. This is lower as compared to other studies. This can be attributed to the fact that earlier studies have been done on asymptomatic patients only. The present study was done to correlate between normal asymptomatic versus foot pain patients. There was a significant difference in the AH and AHI between our two study groups

DESIGN, DEVELOPMENT AND FABRICATION OF MOUTH-DISSOLVING TABLETS CONTAINING EXTRACT OF TRIBULUS TERRESTRIS FOR THE TREATMENT OF HYPERTENSION

Objective: The present work is aim to design, development and fabrication of mouth dissolving tablets containing extract of Tribulus terrestris for the treatment of hypertension. Methods: The extract of fruits of Tribulus terrestris was formulated as mouth dissolving tablets (MDTs) by full factorial design at 32 levels and prepared by direct compression method using super integrants like sodium starch glycolate and cross povidone. Furthermore, the tablet was evaluated for thickness, hardness, weight variation, wetting time, disintegration time, and in vitro drug release study. Results: The tablets were analyzed for a variety of characteristics, such as hardness (2.4-2.9 kg/cm2), friability (0.33-1.7%), disintegration time (20-34 s), drug content (95.32-99.09%), water uptake ratio (26-48%), wetting time (29-69 s), and in vitro drug release illustrated in 5 min (99.04-68.21%). There was no interaction between both the drug and the polymer, according to FTIR and DSC studies. Conclusion: The research revealed that Tribulus terrestris fruits extract can be designed, developed and fabricated into mouth dissolving tablet for the treatment of hypertension with improved bioavailability and expected patient compliance

Quantum chemical study on gas phase decomposition of ferulic acid

<p>Ferulic acid, representing phenolic fraction of bio-oil, is considered to be a model compound in this study for its decomposition into various end products such as ethylbenzene, eugenol, <i>cis</i>-isoeugenol, vanillin, 4-ethylguaiacol, guaiacol, and acetovanillone using density functional theory approach. Results of bond dissociation energies indicate that cleavage of methyl group from ferulic acid is the lowest energy-demanding bond scission amongst all 14 bond cleavages. Primary end product by decomposition of ferulic acid is found to be ethylbenzene and its production occurs through the formation of intermediate products such as 4-hydroxycinnamic acid, cinnamic acid and styrene. Demethoxylation of ferulic acid gives rise to the production of 4-hydroxycinnamic acid which further undergoes the formation of cinnamic acid by dehydroxylation reaction route. The formation of cinnamic acid in this study is carried out using three reaction schemes 1–3 and its further reduction to ethylbenzene is performed using two reaction possibilities. Finally, favourable pathway is found to be decarboxylation of cinnamic acid to produce vinylbenzene followed by the production of ethylbenzene using hydrogenation of C=C chain double bond. Furthermore, thermochemistry of each reaction scheme is performed at atmospheric pressure and at a wide range of temperature of 598–898 K.</p