A simultaneous derivatization of 3-monochloropropanediol and 1,3-dichloropropane with hexamethyldisilazane–trimethylsilyl trifluoromethanesulfonate at room temperature for efficient analysis of food sample analysis

An efficient route to acylated acyclic nucleosides containing a branched hemiaminal ether moiety is reported via three-component alkylation of N-heterocycle (purine nucleobase) with acetal (cyclic or acyclic, variously branched) and anhydride (preferentially acetic anhydride). The procedure employs cheap and easily available acetals, acetic anhydride, and trimethylsilyl trifluoromethanesulfonate (TMSOTf). The multi-component reaction is carried out in acetonitrile at room temperature for 15 min and provides moderate to high yields (up to 88%) of diverse acyclonucleosides branched at the aliphatic side chain. The procedure exhibits a broad substrate scope of N-heterocycles and acetals, and, in the case of purine derivatives, also excellent regioselectivity, giving almost exclusively N-9 isomers.

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Experimental Study of Dredged Sediment Sample Analysis and Solidification in Waterway Regulation Engineering

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.638-640.1252 ◽

2014 ◽

Vol 638-640 ◽

pp. 1252-1256 ◽

Cited By ~ 1

Author(s):

Gui Lan Tao ◽

Xiao Lin Shi ◽

Chao Hua Jiang ◽

Xing Guo Feng ◽

Liang Shu

Keyword(s):

Experimental Study ◽

Unconfined Compressive Strength ◽

Room Temperature ◽

Construction Material ◽

Standard Condition ◽

Environment Protection ◽

Dredged Sediment ◽

Sample Analysis ◽

Alternative Materials ◽

Recycling Technique

How to treat dredged sediment is one of the main environmental problems and the recycling technique is the best way to deal with this problem. This paper deals with the feasibility of beach protection project alternative materials-dredged sand, applies cement and addition to solidify it. The components of dredged sediment and the physical properties were analyzed. Specimens with a designed mix ratio of the cement and dredged sediment were made by means of instant formation. The specimens were cured under standard condition and room temperature. The unconfined compressive strength of specimens were measured after curing for 7, 14 and 28 days. Using solidified dredged sediment as construction material has advantages of technology, economy and environment protection.

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THE REACTION OF DIOXANE WITH HYDROGEN BROMIDE

Canadian Journal of Chemistry ◽

10.1139/v51-090 ◽

1951 ◽

Vol 29 (9) ◽

pp. 785-789 ◽

Cited By ~ 2

Author(s):

A. B. Van Cleave ◽

R. I. Blake

Keyword(s):

Molecular Weight ◽

Hydrobromic Acid ◽

Room Temperature ◽

Hydrogen Bromide ◽

Intermediate Compound ◽

Molecular Weight Determination ◽

Sample Analysis ◽

Ethylene Dibromide ◽

Free Hydrogen ◽

Oxonium Salt

Dioxane reacted slowly at room temperature with anhydrous, bromine free hydrogen bromide to form 2, 2′-dibromodiethyl ether as a principal product. The 2, 2′-dibromodiethyl ether was characterized by comparison with a known sample, analysis, molecular weight determination, and by conversion to divinyl ether which was subsequently brominated to yield 1, 1′, 2, 2′-tetrabromodiethyl ether. When refluxed with constant boiling hydrobromic acid 2, 2′-dibromodiethyl ether was partially converted to ethylene dibromide. An intermediate compound in the formation of 2, 2′-dibromodiethyl ether from dioxane and hydrogen bromide was isolated by solvent extraction using petroleum ether. Its properties indicated that it was probably an oxonium salt.

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Aktivitas Antioksidan Bubuk Sargassum hystrix Selama Penyimpanan pada Suhu Berbeda

Jurnal Agritech ◽

10.22146/agritech.18134 ◽

2020 ◽

Vol 40 (3) ◽

pp. 175

Author(s):

Pingkan Mayestika Afgatiani ◽

Amir Husni ◽

Siti Ari Budhiyanti

Keyword(s):

Antioxidant Activity ◽

Water Content ◽

Room Temperature ◽

Storage Time ◽

Storage Temperature ◽

Total Phenol ◽

Gas Chromatography Mass Spectrometry ◽

Sample Analysis ◽

Ic50 Value ◽

Before And After

The aim of this study was to determine the effect of storage temperature on the antioxidant activity of Sargassum hystrix. Samples were collected from Sepanjang Beach Gunung Kidul, Yogyakarta, and dried, pulverized, and then stored for two months at room temperature (17-33 °C), refrigerator (4 °C) and freezer (-18°C). Furthermore, the samples were tested every two weeks to determine their water content, total phenol, DPPH, and FIC. Also, Gas Chromatography-Mass Spectrometry (GC-MS) analysis was performed for two months before and after storage. The results showed that the water content increased after treatments, along with storage time which ranges from 8.55 to 14.27 %. Total phenol before storage was 175.73 mg GAE/g extract, and freezing has the highest total phenol levels after storage which was 22.07 mg GAE/g extract. Also, DPPH testing showed S. hystrix has anIC50 value of 0.45 mg/mL, and refrigeration has the lowest IC50 value of 3.18 mg/mL. FIC test showed IC50 value of 1.44 mg/mL, and freezing has the lowest FIC IC50 value of 15.36 mg/mL. In addition, GC-MS sample analysis before storage detected 8 compounds with antioxidant activity of 86.96 %. After two months, they were detected at room temperature, refrigerator, and freezing which are 4, 3, and 8 compounds respectively.

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