Infrared Study of Acetic Acid Solutions in CCl4

1995 ◽  
Vol 60 (7) ◽  
pp. 1094-1100 ◽  
Author(s):  
Ivona Malijevská ◽  
Martin Polášek
Keyword(s):  
Acetic Acid ◽  
Regression Analysis ◽  
Carbon Tetrachloride ◽  
Room Temperature ◽  
Equilibrium Constants ◽  
Acid Solutions ◽  
Standard State ◽  
Infrared Study ◽  
Mean Values ◽  
Linear Dimer

Spectra of acetic acid solutions in carbon tetrachloride were taken at room temperature over the concentration range 0.025-0.00125 mol dm-3. Solutions of acetic acid were modelled as an ideal mixture of monomers, and cyclic and linear dimers. Regression analysis effected separation of the experimental envelope into its component bands. Band shapes were approximated by a Lorenzian function with the resolved band peak frequencies 1 712 cm-1 for the cyclic dimer, 1 724 cm-1 for the linear dimer and 1 765 cm-1 for the acetic acid monomer. Mean values of equilibrium constants for the standard state of unit concentration are 2 700 for the cyclic and 393 for the linear dimer, respectively.

Hydrogen bonding of alcohols with AOT in carbon tetrachloride: an infrared study

1985 ◽  
Vol 63 (12) ◽  
pp. 3367-3370 ◽  
Author(s):  
Pierre Ménassa ◽  
Camille Sandorfy
Keyword(s):  
Hydrogen Bonding ◽  
Infrared Spectroscopy ◽  
Carbon Tetrachloride ◽  
Equilibrium Constants ◽  
Short Chain ◽  
Infrared Study ◽  
Free Band ◽  
Long Chain ◽  
Cyclic Alcohols ◽  
Aliphatic Chains

The interaction of the inverted micelles of AOT (sodium di(2-ethylhexyl)sulfosuccinate) with different alcohols due to hydrogen bonding has been studied by means of infrared spectroscopy. Spectra of solutions of the alcohols with increasing concentrations of AOT showed a decrease in the intensity of the free OH stretching band. At the same time a new OH band due to a H-bonded alcohol-inverted micelle complex appears and its intensity increases as the intensity of the free band decreases. Calculated values of the equilibrium constants for the formation of the complexes n-alcohol–AOT, showed a decrease in alcohol–AOT association with the increase of the length of the aliphatic chains in the n-alcohols. Surprisingly, cholesterol behaved like a short chain while other cyclic alcohols like long chain alcohols.

scholarly journals Concentrations of Formic Acid, Acetic Acid, and Ammonia in Newly Constructed Houses

2020 ◽  
Vol 17 (6) ◽  
pp. 1940
Author(s):  
Norimichi Suzuki ◽  
Hiroko Nakaoka ◽  
Akifumi Eguchi ◽  
Masamichi Hanazato ◽  
Yoshitake Nakayama ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Formic Acid ◽  
Indoor Air ◽  
Room Temperature ◽  
Steel Structures ◽  
Living Room ◽  
Outdoor Air ◽  
Mean Values ◽  
Air Samples ◽  
The Mean

Herein, the concentrations of formic acid, acetic acid, and ammonia in samples of indoor air for 47 new houses were measured two weeks after completion. The houses were fabricated with light-gauge steel structures. The measurements were performed in living rooms and bedrooms without furniture and outdoors. Air samples were analyzed using ion chromatography. The mean values were 28 (living room), 30 (bedroom), and 20 μg m−3 (outdoor air) for formic acid; 166 (living room), 151 (bedroom), and 51 μg m−3 (outdoor air) for acetic acid; and 73 (living room), 76 (bedroom), and 21 μg m−3 (outdoor air) for ammonia. The total values of the three substances accounted for 39.4–40.7% of the sum of chemical compound values. The analyzed compounds were indicated by two principal components (PC), PC1 (30.1%) and PC2 (9%), with 39.1% total variance. Formic acid, acetic acid, and ammonia were positively aligned with PC1 and negatively aligned with PC2. Factors such as room temperature, aldehydes, and phthalates were positively aligned with PC1 and negatively aligned with PC2. Furthermore, concentrations of formic acid, acetic acid, and ammonia were significantly and positively correlated with room temperature (p < 0.05).

EQUILIBRIUM CONSTANTS OF ZINC(II) AND COPPER(II) WITH HEMATOPORPHYRIN IX

1966 ◽  
Vol 44 (18) ◽  
pp. 2157-2164 ◽  
Author(s):  
D. A. Brisbin ◽  
R. J. Balahura
Keyword(s):  
Acetic Acid ◽  
Glacial Acetic Acid ◽  
Equilibrium Constants ◽  
Acid Solutions ◽  
Displacement Reactions ◽  
Hematoporphyrin Ix

Equilibrium constants have been measured for the following displacement reactions between copper(II) and zinc(II) with hematoporphyrin IX.[Formula: see text]Preliminary measurements have also been made for the reactions of Mn(II) and Co(II) with hematoporphyrin IX in glacial acetic acid solutions.

Determination of Urine Dopamine

1962 ◽  
Vol 8 (4) ◽  
pp. 370-377 ◽  
Author(s):  
Fritz Bischoff ◽  
Adolfo Torres
Keyword(s):  
Acetic Acid ◽  
Room Temperature ◽  
Cirrhosis Of The Liver ◽  
Internal Standards ◽  
Mean Values ◽  
Normal Individuals ◽  
Reaction Proceeds ◽  
Urinary Dopamine ◽  
The Mean

Abstract The Duliere and Raper conversion of dopamine to 5,6-hydroxyindole is applied to urinary dopamine, which is concentrated and recovered by adsorption (pH 8.5-9.0) on and elution with dilute acetic acid from alumina. The spectrofluorometric readings are made at pH 5.3, with activation and fluorescence at 320 and 375 mµ, respectively. Proportionality between high and low internal standards is achieved when the 5,6-hydroxyindole reaction proceeds for 20 hours at room temperature. The increase of fluorescence with time adds specificity to the test. The recovery of standards added before adsorption on alumina compared with standards added after elution was 98 per cent. Urinary dopamine was determined in normal individuals asleep and awake and in those with a number of pathologic conditions. The mean values were decreased in groups with Parkinsonism, diabetes, and cirrhosis of the liver. The study included 2 patients with pheochromocytoma.

Circular dichroism and infrared study of β-turn formation in repeat peptides of elastin

1987 ◽  
Vol 52 (5) ◽  
pp. 1356-1361
Author(s):  
S. Abdel Rahman ◽  
M. Elsafty ◽  
A. Hattaba
Keyword(s):  
Circular Dichroism ◽  
Solid State ◽  
Ir Spectra ◽  
Chain Length ◽  
Room Temperature ◽  
Infrared Study ◽  
Feature Characteristic ◽  
C 50 ◽  
The Stability ◽  
Circular Dichroïsm

The conformation of elastin-like peptides Boc-Ala-Pro-Gly-Val-APEGM, Boc-Ala-Pro-Gly-Val-Gly-Val-APEGM, Boc-Ala-Pro-Gly-Val-Ala-Pro-Gly-Val-Gly-Val-APEGM, Boc-Ala-Pro-Gly-Val-Gly-Val-Ala-Pro-Gly-Val-Gly-Val-APEGM were examined in solution using circular dichroism at 30 °C, 50 °C, and 70 °C and in solid state by IR at room temperature. The studies show that the β-turn is a significant conformational feature for peptides under investigation in solution at 30 °C and 50 °C, but at 70 °C the tetra, hexa, and decapeptides show the CD feature characteristic of the β-structure while the dodecapeptide spectra show the presence of β-turn which indicates the stability of the β-turn at this chain length. The IR spectra show that in the solid state at room temperature all investigated peptides assume essentially a β-turn except the tetrapeptide which present evidence of antiparallel β-structure. The β-turn contribution in the IR spectra increases with the increase of the chain length of the peptide.

scholarly journals Factors associated with the use of fashion braces of the Saudi Arabian Youth: application of the Health Belief Model

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Anwar S. Alhazmi ◽  
Dania E. Al Agili ◽  
Mohammed S. Aldossary ◽  
Shaker M. Hakami ◽  
Bashaer Y. Almalki ◽  
...  
Keyword(s):  
Regression Analysis ◽  
Family Income ◽  
Health Belief ◽  
Intention To Use ◽  
Perceived Susceptibility ◽  
Mean Values ◽  
Factors Associated ◽  
The Mean ◽  
Belief Model ◽  
The Health Belief Model

Abstract Background In spite of the fact that fashion braces (FBs) have been in the spotlight in recent years among both orthodontists and the general public in several countries, there is still limited evidence regarding FBs. The aim was to identify health-related behaviors in using FBs by considering the Health Belief Model (HBM). Methods A cross-sectional study with a random sampling technique was conducted in Jazan, Saudi Arabia. The data was obtained from different middle and high schools students, and first-year students at Jazan University. The questionnaire collected data on demographic characteristics and 27 items to examine the constructs of the HBM. Chi Square test was carried out to establish the factors associated with using, the intention to use, and previous knowledge on the use of fashion braces. Logistic regression analysis was utilized to determine the factors associated with the use of fashion braces. Results 406 study participants completed the questionnaire with a response rate of 88.3%. Majority of respondents were males (52.2%) and > 19 years old (44.3%). Only 9.9% students had used the FBs. However, 25.7% of students had the intention to use them. The perceived susceptibility, perceived benefits and cues to action constructs scores were fair with the mean values of 15.38 (SD = 9.4), 28.17 (SD = 10.8) and 6.65 (SD = 2.50), respectively. However, the perceived barrier score was high with the mean values of 22.14 (SD = 7.50), and lower score of self-efficacy with mean of 8.73 (SD = 3.30). Gender, age, monthly income (family), and education level were significantly (p < 0.05) associated with the use of fashion braces among the study’s participants. Based on the results of logistic regression analysis family income, perceived susceptibility, and risk severity constructs predict the use of fashion braces in the study's sample. Conclusions The current study suggests that the family income, perceived susceptibility, and risk severity of students significantly influence the use of fashion braces. Hence, it is recommended that researchers should investigate effective educational strategies and programs for improving young people’s knowledge about fashion braces and focus more on low family income students so that their using of fashion brace will be decreased.

Durability of Red Mud Based Geopolymer Paste in Acid Solutions

2016 ◽  
Vol 866 ◽  
pp. 99-105 ◽  
Author(s):  
Smita Singh ◽  
M.U. Aswath ◽  
R.V. Ranganath
Keyword(s):  
Mechanical Properties ◽  
Acetic Acid ◽  
Fly Ash ◽  
Red Mud ◽  
Acetic Acid Solution ◽  
Strength Loss ◽  
Acid Solutions ◽  
Test Results ◽  
Acid Attack ◽  
Geopolymer Paste

The present investigation is on the effect of red mud on the mechanical properties and durability of the geopolymer paste in sulphuric and acetic acid solution. Red mud and fly ash were used to form the geopolymer paste along with the alkalies. The variation of red mud in the paste composition was from 0% to 90%. Cylindrical shaped specimens of 1 inch diameter and 1 inch height were prepared. The specimens were immersed in 5% sulphuric acid and 5% acetic acid for 1, 7, 14, 28, 56 and 84 days and tested for weight loss, visual deformation, strength loss and colour of the solvent, based on the procedure specified by ASTM C 267 – 01. SEM/EDX Tests were performed on the geopolymer specimens. Test results show that initially, the strength of the geopolymer increased upon the addition of red mud. The strength was maximum when the percentage of red mud was 30%. The maximum strength obtained was 38 MPa for the paste containing 30% red mud using 10M alkali solution as against 31.69 MPa, when only fly ash was used. Geopolymer paste containing 30% and 50% red mud showed better resistance to acid attack. The strength loss was minimum for the samples containing 30% red mud in both inorganic and organic acid i.e. sulphuric and acetic acid.

Color and Antioxidant Changes in Various Natural Rubber Processes

2015 ◽  
Vol 754-755 ◽  
pp. 230-234 ◽  
Author(s):  
Suwimon Siriwong ◽  
Adisai Rungvichaniwat ◽  
Pairote Klinpituksa ◽  
Khalid Hamid Musa ◽  
Aminah Abdullah
Keyword(s):  
Acetic Acid ◽  
Natural Rubber ◽  
Retention Index ◽  
Total Phenolic Content ◽  
Room Temperature ◽  
Phenolic Content ◽  
Total Phenolic ◽  
Lovibond Colorimeter

Fresh field natural rubber was coagulated by acetic acid, soaked in water at room temperature (WRT) or 70°C (W70) for 1 hr, and then dried in an oven at 40°C. Non-soaked natural rubber samples (NoW) served as a control. Two grades of natural rubber, namely air-dry sheet (ADS) and ribbed smoked sheet No.3 (RSS3) derived from the same latex, were also investigated. All dry rubber samples were characterized with Lovibond colorimeter according to ASTM D3157, as well as with a HunterLab spectrophotometer. Furthermore, all the dry rubber samples were dissolved in a chloroform:methanol mixture (4:1 v:v). The rubber was then precipitated out of the solution with methanol, and the remaining solution was quantitatively analyzed for total phenolic content (TPC). The plasticity retention index (PRI) was determined for all the dried rubber samples according to ASTM D3194. It was found that WRT, W70 and ADS were similar in lightness L*, while RSS3 had the lowest L*. W70 had the lowest redness a*, which increased in the order WRT, NoW, RSS3 and ADS. W70 also had the lowest yellowness b*, which increased in the order RSS3, NoW and WRT and ADS. Moreover, TPC was the lowest for the W70 sample, increasing in the order ADS, WRT, NoW and RSS3. The PRI was highest for W70, and decreased in the order WRT, RSS3, NoW and ADS. All of the PRI values observed were comparatively high relative to blocked standard Thai rubber 20 (STR20).

scholarly journals Synthesis of spiro[dihydropyridine-oxindoles] via three-component reaction of arylamine, isatin and cyclopentane-1,3-dione

2013 ◽  
Vol 9 ◽  
pp. 8-14 ◽  
Author(s):  
Yan Sun ◽  
Jing Sun ◽  
Chao-Guo Yan
Keyword(s):  
Acetic Acid ◽  
Reaction Mechanism ◽  
Room Temperature ◽  
The Other ◽  
Other Hand ◽  
Three Component Reaction ◽  
High Yields

A fast and convenient protocol for the synthesis of novel spiro[dihydropyridine-oxindole] derivatives in satisfactory yields was developed by the three-component reactions of arylamine, isatin and cyclopentane-1,3-dione in acetic acid at room temperature. On the other hand the condensation of isatin with two equivalents of cyclopentane-1,3-dione gave 3,3-bis(2-hydroxy-5-oxo-cyclopent-1-enyl)oxindole in high yields. The reaction mechanism and substrate scope of this novel reaction is briefly discussed.

scholarly journals REGULATORY MECHANISMS OF CELLULAR RESPIRATION

1950 ◽  
Vol 34 (2) ◽  
pp. 211-224 ◽  
Author(s):  
E. S. Guzman Barron ◽  
Maria Isabel Ardao ◽  
Marion Hearon
Keyword(s):  
Acetic Acid ◽  
Pyruvic Acid ◽  
No Oxidation ◽  
Yeast Cells ◽  
Acid Formation ◽  
Cellular Respiration ◽  
Acid Oxidase ◽  
Acid Solutions ◽  
Fluoroacetic Acid ◽  
A Cell

The rate of the aerobic metabolism of pyruvic acid by bakers' yeast cells is determined mainly by the amount of undissociated acid present. As a consequence, the greatest rate of oxidation was observed at pH 2.8. Oxidation, at a slow rate, started at pH 1.08; at pH 9.4 there was no oxidation at all. The anaerobic metabolism, only a fraction of the aerobic, was observed only in acid solutions. There was none at pH values higher than 3. Pyruvic acid in the presence of oxygen was oxidized directly to acetic acid; in the absence of oxygen it was metabolized mainly by dismutation to lactic and acetic acids, and CO2. Acetic acid formation was demonstrated on oxidation of pyruvic acid at pH 1.91, and on addition of fluoroacetic acid. Succinic acid formation was shown by addition of malonic acid. These metabolic pathways in a cell so rich in carboxylase may be explained by the arrangement of enzymes within the cell, so that carboxylase is at the center, while pyruvic acid oxidase is located at the periphery. Succinic and citric acids were oxidized only in acid solutions up to pH 4. Malic and α-ketoglutaric acids were not oxidized, undoubtedly because of lack of penetration.

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