scholarly journals SYNTHESIS AND CONFORMATION OF p-(AMINO)BUTOXYCALIX[4]ARENE

2010 ◽  
Vol 7 (1) ◽  
pp. 49-57
Author(s):  
Firdaus Firdaus ◽  
Jumina Jumina ◽  
Hardjono Sastrohamidjojo
Keyword(s):  
Acetic Acid ◽  
Solvent Mixture ◽  
Reduction Reaction ◽  
Nitrogen Atmosphere ◽  
Reduction Reactions ◽  
Partial Cone ◽  
Acetic Acid Glacial

Derivatization of 5,11,17,23-tetra-t-butyl-25,26,27,28-tetrahydroxycalix[4]-arene to 5,11,17,23-tetra-amino-25,26,27,28-tetrabutoxycalix[4]arene compound via etherification, ipso nitration, and reduction reactions, respectively has been conducted. The etherification reaction was carried out by refluxed the mixture of 5,11,17,23-tetra-t-butyl-25,26,27,28-tetrahydroxy-calix[4]arene, 1-bromobutane, NaI, and NaH in solvent mixture of THF-DMF (10:1 v/v) and nitrogen atmosphere for 4 hours to resulted 5,11,17,23-tetra-t-butyl-25,26,27,28-tetrabutoxycalix[4]-arene 84% in yield; ipso nitration reaction was carried out by stirred the mixture of 5,11,17,23-tetra-t-butyl-25,26,27,28-tetrabutoxycalix[4]arene and HNO3 100% in solvent mixture of dichloromethane-acetic acid glacial (1:1 v/v) for 2 hours and than refluxed for 1 hour to resulted 5,11,17,23-tetra-nitro-25,26,27,28-tetra-butoxycalix[4]arene 50% in yield; and reduction reaction was carried out by refluxed the mixture of 5,11,17,23-tetra-nitro-25,26,27,28-tetrabutoxycalix[4]arene and SnCl2/HCl reductor in ethanol solvent for 6 hours to resulted 5,11,17,23-tetra-amino-25,26,27,28-tetrabutoxycalix[4]arene 67% in yield. In the etherification reaction, the conformation of calix[4]arene compound was converted from cone to partial cone; but in the followed reactions, i.e. nitration and reduction reactions, the conformation of calix[4]arene compounds were remain in partial cone.   Keywords: aminobutoxycalixarene, conformation, etherification, ipso nitration, reduction

scholarly journals One-pot synthesis of hollow hydrangea Au nanoparticles as a dual catalyst with SERS activity for in situ monitoring of a reduction reaction

RSC Advances ◽  
2019 ◽  
Vol 9 (18) ◽  
pp. 10314-10319 ◽  
Author(s):  
Yazhou Qin ◽  
Yuxiang Lu ◽  
Wufan Pan ◽  
Dongdong Yu ◽  
Jianguang Zhou
Keyword(s):  
Au Nanoparticles ◽  
Reduction Reaction ◽  
In Situ Monitoring ◽  
One Pot ◽  
Reduction Reactions ◽  
One Pot Synthesis

We prepared hollow flower-shaped Au nanoparticles as a bifunctional material by a one-pot method for in situ monitoring of reduction reactions.

Heteroatom-Doped Nanomaterials/Core–Shell Nanostructures Based Electrocatalysts for Oxygen Reduction Reaction

2021 ◽  
Author(s):  
Saravanan Nagappan ◽  
Malarkodi Duraivel ◽  
Shamim Ahmed Hira ◽  
Kandasamy Prabakar ◽  
Chang-Sik Ha ◽  
...  
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Environmental Conditions ◽  
Reduction Reaction ◽  
Core Shell ◽  
Reduction Reactions ◽  
Oxygen Reduction Reactions ◽  
Shell Nanostructures ◽  
Doped Nanomaterials

Recently, heteroatom doped core–shell nanostructures (HCSNs) have been widely used as superior electrocatalysts for oxygen reduction reactions (ORRs) owing to their enhanced ORR performance and stability under harsh environmental conditions....

Determination of the Iodine Value of Oils and Fats: Summary of Collaborative Study

1994 ◽  
Vol 77 (3) ◽  
pp. 674-676 ◽  
Author(s):  
David Firestone
Keyword(s):  
Acetic Acid ◽  
Iodine Value ◽  
Collaborative Study ◽  
Solvent Mixture ◽  
Acid Mixture ◽  
Collaborative Studies ◽  
Wide Range ◽  
Aoac Method ◽  
Iodine Values

Abstract Two collaborative studies were conducted using the Wijs method for determining the iodine value in a wide range of vegetable and animal oils and fats. The results obtained when using carbon tetrachlo-ride were compared to those obtained when using a substitute solvent mixture of cyclohexane and glacial acetic acid. The values reported for the iodine values indicate that the cyclohexane and acetic acid mixture can be used in place of carbon tetrachloride without loss of precision. The method has been adopted first action by AOAC INTERNATIONAL as an IUPAC/AOCS/AOAC method.

Bathochromic shift of the Q-bands of octakis(p-t-butylbenzyloxy)phthalocyanines with magnesium(II), nickel(II) and copper(II) in a solvent mixture of chloroform and acetic acid

2005 ◽  
Vol 09 (09) ◽  
pp. 646-650 ◽  
Author(s):  
Kuninobu Kasuga ◽  
Katsuyori Yashiki ◽  
Tamotsu Sugimori ◽  
Makoto Handa
Keyword(s):  
Acetic Acid ◽  
Trifluoroacetic Acid ◽  
Bathochromic Shift ◽  
Solvent Mixture ◽  
Red Shift ◽  
Weak Band ◽  
Propanol Solution ◽  
Phthalocyanine Ring

1,4,8,11,15,18,22,25-octakis(p-t-butylbenzyloxy)phthalocyanine complexes of magnesium(II), nickel(II) and copper(II) were prepared by refluxing the propanol solution of 3,6-di(p-t-butylbenzyloxy)phthalonitrile in the presence of magnesium turnings. The complexes showed intense Q-bands between 740 and 750 nm in chloroform. The magnesium(II) complex showed an additional weak band at 807 nm in chloroform, while the nickel(II) and copper(II) did not. The Q-band of the magnesium(II) species was red-shifted with increase of acetic acid in the solvent mixture of chloroform and acetic acid; 745, (765, 807) and (810, 868 nm) in chloroform, 0.1% (v/v) acetic acid and 60% (v/v) acetic acid, respectively. The magnesium(II) complex has bands at 900 and 999 nm in trifluoroacetic acid. In the solvent mixture of 1% (v/v) acetic acid, the red-shift of the Q-band was larger for the magnesium(II) derivative, a little for the nickel(II) and scarcely for the copper(II), respectively. The shift was explained by protonation of the external nitrogen atoms of the phthalocyanine ring.

Electrospun Gelatin Fiber Bundles by Self-Bundling Electrospinning

2015 ◽  
Vol 1105 ◽  
pp. 190-194 ◽  
Author(s):  
Patcharaporn Thitiwongsawet ◽  
Boonchuay Wisesanupong ◽  
Supatcharee Pukkanasut
Keyword(s):  
Electrical Conductivity ◽  
Acetic Acid ◽  
Solvent Mixture ◽  
Electrospinning Process ◽  
Single Fiber ◽  
Fiber Bundles ◽  
Electrospun Gelatin

Electrospun gelatin fiber bundles were successfully prepared by self-bundling electrospinning process. A solvent mixture of 80:20 v/v acetic acid: N,N-dimethylacetamide was used as solvent for gelatin. Self-bundling was achieved by using of a grounded needle tip at the beginning of electrospinning process. Gelatin fiber bundles were fabricated from 30% w/v gelatin solutions with addition of pyridinium formate (PF) at concentrations of 3 and 5% w/v. The averaged diameters of single fiber were 452 and 410 nm, respectively; whereas, the averaged diameter of bundles were 17.2 and 22.3 μm, respectively. Viscosity and electrical conductivity of solutions were important parameters for achieving self-bundling electrospinning. Gelatin solutions with optimum electrical conductivity and viscosity could yield bundles by self-bundling electrospinning.

The bromination and chlorination of 2,3-dialkylindoles. Isolation of 3-bromo- and 3-chloro-2,3-dialkylindolenines and acid catalyzed conversion to 3-methoxyindolenines

1980 ◽  
Vol 58 (8) ◽  
pp. 808-814 ◽  
Author(s):  
Gary I. Dmitrienko ◽  
Edward A. Gross ◽  
Susan F. Vice
Keyword(s):  
Acetic Acid ◽  
Good Yield ◽  
Room Temperature ◽  
Chemical Properties ◽  
Nitrogen Atmosphere ◽  
Crystalline Solid ◽  
Tert Butyl ◽  
Acidic Conditions ◽  
Acid Catalyzed

The bromination of 2,3-dimethylindole in acetic acid followed by hydrolysis has been shown to yield the known dimer 16 of 3-hydroxy-2,3-dimethylindolenine 15 and not 3-hydroxymethyl-2-methylindole 12 as reported previously by others. Bromination of 2,3-dimethylindole in the presence of triethylamine has yielded 3-bromo-2,3-dimethylindolenine 17 as a crystalline solid which is stable at room temperature in a nitrogen atmosphere in the presence of triethylamine but decomposes vigorously in the absence of base. Under mildly acidic conditions 17 reacts rapidly with methanol to yield 3-methoxy-2,3-dimethylindolenine 3 in good yield. With tert-butyl hypochlorite in the presence of triethylamine, 2,3-dimethylindole gives 3-chloro-2,3-dimethylindolenine 2 which has chemical properties similar to 17 reacting readily with methanol to give 3. Similarly tetrahydrocarbazole was converted to the analogous chloroindolenine 5 and bromoindolenine 18 both of which readily underwent methanolysis to give 6 in good yield. A mechanism for the acid catalyzed methanolysis of 3-chloro- and 3-bromoindolenines is proposed.

scholarly journals Improvement of Dissolution Properties Through Acyclovir - Succinic Acid Cocrystal Using Solvent Evaporation Technique

2017 ◽  
Vol 7 (04) ◽  
Author(s):  
Hilya Nur Imtihani ◽  
Agnes Nuniek W ◽  
Dwi Setyawan ◽  
Esti Hendradi
Keyword(s):  
Acetic Acid ◽  
Melting Point ◽  
Succinic Acid ◽  
Dissolution Rate ◽  
Sem Analysis ◽  
Solvent Evaporation ◽  
Dissolution Properties ◽  
Ethanol Acetic Acid ◽  
Evaporation Technique ◽  
Acetic Acid Glacial

The objective of this research was to prepared acyclovir cocrystals with succinic acid as coformer using three different solvents (ethanol, acetic acid glacial, and 0.1N HCl) to influence the characters and improve the dissolution rate of acyclovir. Cocrystallization of acyclovir with succinic acid as coformer was successfully prepared by solvent evaporation technique using three different solvents (ethanol, acetic acid glacial, and 0.1N HCl). The screening indicated that acyclovir formed novel cocrystals with succinic acid in the three different solvents. PXRD profile show that there is three peaks in ethanol cocrystal in angle 2θ 5.9134o ; 9.1645o and 13.4044o . For acetic acid glacial and 0.1N HCl cocrystal there is one peak in angle 2θ 5.9263o and 2θ 9.6011o . In analysis diffractogram DSC formed ethanol cocrystal with melting point 175.84oC. The melting point of acetic acid glacial cocrystal is 178.41oC and 0.1N HCl cocrystal is 156.75oC. The dissolution rate of the cocrystals measured by the effisiency disolution (ED45) that considerable faster than that pure acyclovir and the physical mixtures. On the result of FTIR analysis there is changes of the wavenumber that indicated that there is cocrystal formed. And for SEM analysis, morphology of cocrystals was different than the original materials. In dissolution test, ethanol and acetic acid glacial cocrystals have better efficiency dissolution (ED45) (92.96 %) than the acyclovir ED45 (84.48 %). But 0.1N HCl cocrystal has lower ED45 than acyclovir that is 48.19 %. The results obtained in this research indicated the acyclovir cocrystals have formed with succinic acid as coformer using three different solvents. The physical properties was different from the three cocrystals. Dissolution rate of acyclovir cocrystals using ethanol and acetic acid glacial solvents was increase, whereas using 0.1N HCl was decrease rather than pure acyclovir

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