scholarly journals The improved photostability of naproxen in the inclusion complex with 2-hydroxypropyl-β-cyclodextrin

2015 ◽  
Vol 69 (4) ◽  
pp. 361-370 ◽  
Author(s):  
Snezana Ilic-Stojanovic ◽  
Vesna Nikolic ◽  
Ljubisa Nikolic ◽  
Aleksandar Zdravkovic ◽  
Agnes Kapor ◽  
...  
Keyword(s):  
Inclusion Complex ◽  
Chemical Properties ◽  
Precipitation Method ◽  
Molar Ratio ◽  
Physical And Chemical Properties ◽  
Ftir Analysis ◽  
Molecular Inclusion ◽  
Co Precipitation ◽  
Physical And Chemical ◽  
And Chemical Properties

The aim of this work was the preparation of the inclusion complex of naproxen with 2-hydroxypropyl-?-cyclodextrin (HP-?-CD) in order to improve the physical and chemical properties of naproxen. The molecular inclusion complexes of naproxen with HP-?-CD were prepared by using the co-precipitation method in the solid state with the molar ratio of 1:1. The structure of the obtained complex was characterized by using FTIR, 1H NMR, UV-Vis and XRD methods. The testing of naproxen photostability by the UV-Vis method indicated the degradation to aromatic ketone, 2-acetyl-6-methoxynaphthalene. FTIR analysis showed that the degradation started 15 days after the exposure of naproxen to daylight while the inclusion complex of naproxen: 2-hydroxypropyl-?-cyclodextrin was photostable for a period of 30 days.

Synthesis of Fe3O4 Magnetic Nanoparticles in a Helical Microreactor

2020 ◽  
Vol 842 ◽  
pp. 174-181
Author(s):  
Dan Wang ◽  
Mudassir Iqbal ◽  
Ming Qiao Zhu
Keyword(s):  
Magnetic Nanoparticles ◽  
Saturation Magnetization ◽  
Chemical Properties ◽  
Precipitation Method ◽  
Physical And Chemical Properties ◽  
Reaction Conditions ◽  
Ft Ir ◽  
Co Precipitation ◽  
Physical And Chemical ◽  
And Chemical Properties

Fe3O4 nanoparticles (NPs) have previously been employed in various fields owing to their unique physical and chemical properties. In this paper, Fe3O4 NPs are prepared by co-precipitation method in a helical microreactor under different reaction conditions which affect the size of Fe3O4 NPs. The product is characterized by FT-IR and XPS. Also, VSM characterization shows that Fe3O4 exhibits typical superparamagnetic behavior and the saturation magnetization of NPs is 53 emu/g.

scholarly journals Transesterification of linoleic and oleic sunflower oils to biodiesel using CaO as a solid base catalyst

2012 ◽  
Vol 77 (6) ◽  
pp. 815-832 ◽  
Author(s):  
Zlatica Predojevic ◽  
Biljana Skrbic ◽  
Natasa Djurisic-Mladenovic
Keyword(s):  
Iodine Value ◽  
Chemical Properties ◽  
Acid Methyl Ester ◽  
Acid Value ◽  
Molar Ratio ◽  
Physical And Chemical Properties ◽  
Reaction Parameters ◽  
Sunflower Oils ◽  
Physical And Chemical ◽  
And Chemical Properties

The purpose of this work is to characterize biodiesel (i.e. methyl esters, MEs) produced from linoleic and oleic sunflower oils (LSO and OSO, respectively) by alkali transesterification with methanol and CaO as a heterogeneous catalyst under different reaction parameters. The parameters investigated were the methanol/oil molar ratio (4.5:1, 6:1, 7.5:1, 9:1 and 12:1) and the mass ratio of CaO to oil (2% and 3%). The physical and chemical properties of the feedstocks and MEs, like density at 15oC, kinematic viscosity at 40oC, acid value, iodine value, saponification value, cetane index, fatty acid (methyl ester) composition, were determined in order to investigate the effects of LSO and OSO properties and reaction parameters on the product characteristics, yields and purity. The properties of feedstock had decisive effect on the physical and chemical properties of MEs as majority of them did not differ significantly under studied reaction conditions. The MEs produced generally met the criteria required for commercial biodiesel; in fact, the only exception was in the case of iodine value of ME produced from LSO. The product yields only slightly changed with the applied conditions; the highest yield (99.22%) was obtained for ME-LSO produced at 6 mol% methanol to oil ratio, while the lowest one (93.20%) was for ME-OSO produced under the lowest methanol/oil molar ratio (4.5:1). The applied catalyst amounts had similar influence on the oil conversion to biodiesel. The yields of ME-LSOs were in general somewhat higher than those obtained for ME-OSOs under the same conditions, which was attributed to the influence of the respective feedstocks' acid value and viscosity.

The physical properties of chromium oxide—aluminium oxide catalysts - I. Preparation and adsorption measurements

1954 ◽  
Vol 224 (1158) ◽  
pp. 412-419 ◽  
Keyword(s):  
Chromium Oxide ◽  
Chemical Properties ◽  
Prolonged Treatment ◽  
Physical And Chemical Properties ◽  
Surface Areas ◽  
Wide Range ◽  
Adsorption Of Nitrogen ◽  
Co Precipitation ◽  
Physical And Chemical ◽  
And Chemical Properties

This series of papers concerns relations between the physical and chemical properties of catalysts used for the formation of toluene from heptane. These have been prepared by the co-precipitation of chromium and aluminium oxides in a wide range of proportions. After prolonged treatment with hydrogen at 500°C the surface area was determined by measure­ment of the adsorption of nitrogen at –195∙8°C. The adsorption of hydrogen, heptane and benzene was measured from 0 to 500°C. Surface areas increased as the alumina content was raised. Chemisorption of hydrogen reached a maximum at about 70% Cr 2 O 3 . Results with heptane were obscured by decomposition of the hydrocarbon at temperatures above 200°C.

scholarly journals Alkali-catalyzed production of biodiesel from waste frying oils

2009 ◽  
Vol 74 (8-9) ◽  
pp. 993-1007 ◽  
Author(s):  
Zlatica Predojevic ◽  
Biljana Skrbic
Keyword(s):  
Methyl Esters ◽  
Chemical Properties ◽  
Weight Ratio ◽  
Molar Ratio ◽  
Physical And Chemical Properties ◽  
Reaction Parameters ◽  
Waste Frying Oil ◽  
The Mean ◽  
Physical And Chemical ◽  
And Chemical Properties

The effects of the transesterification parameters on the yield and quality of the methyl esters (MEs) produced from waste frying oil (WFO) were investigated. A two-step alkali transesterification reaction followed by silica gel purification step was applied. The investigated reaction parameters were the methanol/oil molar ratio (6:1 and 9:1), the catalyst/oil weight ratio (1.0 and 1.5 mass %) and the type of catalyst (NaOH and KOH). The physical and chemical properties of the employed feedstock and the obtained biodiesel were determined in order to investigate the effects of both the properties of the WFO and the reaction parameters on the characteristics and yields of the product. It was found that the properties of the feedstock had a determinant effect on the physical and chemical properties of the MEs, as the majority of them did not differ significantly under the studied reaction parameters. However, the reaction parameters influenced the yields of the product. Higher yields were obtained with a 1.0 than with a 1.5 mass % catalyst to oil ratio. The increasing yield with decreasing catalyst/oil ratio was more pronounced with NaOH (9.15-14.35 %) than with KOH (2.84-6.45 %). When KOH was used as the catalyst, the yields were always higher (the mean yield was 94.86 %) in comparison to those obtained with NaOH (the mean was 84.28 %). Furthermore, the efficiency of KOH in conversion of WFO to purified MEs in comparison to NaOH was even more pronounced in the case of the higher methanol/oil ratio, i.e., for the 9:1 methanol/ oil ratio, the yield increase with KOH was about 2 times higher than the yield with NaOH, regardless of the applied catalyst/oil ratio.

Statistical criteria of stellar population types

1966 ◽  
Vol 24 ◽  
pp. 101-110
Author(s):  
W. Iwanowska
Keyword(s):  
Stellar Population ◽  
Chemical Properties ◽  
Spectrophotometric Study ◽  
Physical And Chemical Properties ◽  
Population Type ◽  
The Galaxy ◽  
Distribution Parameters ◽  
Physical And Chemical ◽  
Statistical Criteria ◽  
And Chemical Properties

In connection with the spectrophotometric study of population-type characteristics of various kinds of stars, a statistical analysis of kinematical and distribution parameters of the same stars is performed at the Toruń Observatory. This has a twofold purpose: first, to provide a practical guide in selecting stars for observing programmes, second, to contribute to the understanding of relations existing between the physical and chemical properties of stars and their kinematics and distribution in the Galaxy.

Response of corn (Zea mays L.) to various organic-based fertilizers in marginal upland of Sta. Rita, Samar

2017 ◽  
pp. 31-43
Author(s):  
Berta Ratilla ◽  
Loreme Cagande ◽  
Othello Capuno
Keyword(s):  
Block Design ◽  
Management Strategies ◽  
Chemical Properties ◽  
Organic Fertilizers ◽  
Growth And Yield ◽  
Physical And Chemical Properties ◽  
Total N ◽  
Randomized Complete Block Design ◽  
Physical And Chemical ◽  
And Chemical Properties

Organic farming is one of the management strategies that improve productivity of marginal uplands. The study aimed to: (1) evaluate effects of various organic-based fertilizers on the growth and yield of corn; (2) determine the appropriate combination for optimum yield; and (3) assess changes on the soil physical and chemical properties. Experiment was laid out in Randomized Complete Block Design, with 3 replications and 7 treatments, namely; T0=(0-0-0); T1=1t ha-1 Evans + 45-30-30kg N, P2O5, K2O ha-1; T2=t ha-1 Wellgrow + 45-30-30kg N, P2O5, K2O ha-1; T3=15t ha-1 chicken dung; T4=10t ha-1 chicken dung + 45-30-30kg N, P2O5, K2O ha-1; T5=15t ha-1 Vermicast; and T6=10t ha-1 Vermicast + 45-30-30kg N, P2O5, K2O ha-1. Application of organic-based fertilizers with or without inorganic fertilizers promoted growth of corn than the control. But due to high infestation of corn silk beetle(Monolepta bifasciata Horns), its grain yield was greatly affected. In the second cropping, except for Evans, any of these fertilizers applied alone or combined with 45-30-30kg N, P2O5, K2O ha-1 appeared appropriate in increasing corn earyield. Soil physical and chemical properties changed with addition of organic fertilizers. While bulk density decreased irrespective of treatments, pH, total N, available P and exchangeable K generally increased more with chicken dung application.

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