Construction and Chemometric Analysis of Acidity Function in Perchloric Acid

1999 ◽  
Vol 64 (8) ◽  
pp. 1253-1261 ◽  
Author(s):  
Eva Jirásková ◽  
Jiří Kulhánek ◽  
Taťjana Nevěčná ◽  
Oldřich Pytela
Keyword(s):  
Perchloric Acid ◽  
Regression Coefficient ◽  
Principal Component ◽  
Acidity Function ◽  
First Principle ◽  
Protonated Forms ◽  
Aqueous Perchloric Acid ◽  
High Degree ◽  
Degree Of Similarity ◽  
Indicator Type

Four 2,6-disubstituted anilines with CH3, Cl, and NO2 substituents have been synthesized and, together with four commercial substances of the same type, subjected to spectrophotometry to find the concentration ratios of the protonated and non-protonated forms in aqueous perchloric acid of 0.02-10.55 mol dm-3 concentration. By a procedure devised earlier, the acidity function has been constructed and the pKa values calculated. The Principal Component Analysis was applied to the acidity function obtained and on other eight acidity functions of perchloric acid were taken from literature. It was found that the first principal component explained 99.78% of variability, which indicated high degree of similarity of the said functions irrespective of the indicator type and solvent used. The regression dependences acidity function values on the first principle component are very close, the regression coefficient expressing the measure of sensitivity of the indicator to the acidifying medium. The pKa values obtained agree well with the literature data.

An acidity scale, [H+]hv, for proton quenching of excited states in aqueous perchloric acid

1989 ◽  
Vol 67 (4) ◽  
pp. 710-719 ◽  
Author(s):  
J. A. Pincock ◽  
P. R. Redden
Keyword(s):  
Excited State ◽  
Activity Coefficient ◽  
Excited States ◽  
Perchloric Acid ◽  
Acidity Function ◽  
Quenching Rate ◽  
Benzyl Alcohols ◽  
Fluorescent Indicator ◽  
Aqueous Perchloric Acid ◽  
Acidity Scale

An acidity scale for excited state protonation kinetics in aqueous perchloric acid has been developed using 1-cyanonaph-thalene as a fluorescent indicator. A comparison of the quenching rate constants obtained using this scale is made with both the more general excess acidity function, X, and the transition state activity coefficient approach. A variety of chromophores were studied including 1- and 2-cyanonaphthalenes, 1- and 2-methoxynaphthalenes, benzyl alcohols, toluenes, benzonitriles, and 2-vinylnaphthalene. Keywords: acidity scale, proton fluorescence quenching.

The ketonization of acetophenone enol in concentrated aqueous sulphuric and perchloric acid solutions. Implication on X acidity function correlations of the enolization reaction and determination of the keto–enol equilibrium constant as a function of acidity

1990 ◽  
Vol 68 (10) ◽  
pp. 1653-1656 ◽  
Author(s):  
Y. Chiang ◽  
A. J. Kresge ◽  
R. A. More O'ferrall ◽  
B. A. Murray ◽  
N. P. Schepp ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Key Words ◽  
Equilibrium Constant ◽  
Perchloric Acid ◽  
Acidity Function ◽  
Acid Solutions ◽  
Function Correlation ◽  
Aqueous Perchloric Acid ◽  
Sulfuric Acid Solutions

Rates of ketonization of the enol of acetophenone, generated by flash photolytic photohydration of phenylacetylene, were measured in aqueous sulfuric and perchloric acid solutions over the concentration range 1–50 wt.% acid; rates of enolization of acetophenone, monitored by bromine scavenging, were also measured in aqueous perchloric acid solutions over the same concentration range. The results suggest that the curvature observed in a previous X acidity function correlation of the rate of enolization in sulfuric acid solutions was an artifact produced by insufficiently efficient scavenging, and that introduction of the activity of water in the correlating expression, used previously to eliminate the curvature and believed to reflect covalent involvement of water in the enolization reaction, is unnecessary. The present results also show that the keto–enol equilibrium constant for acetophenone decreases with increasing acidity in these concentrated sulfuric and perchloric acid solutions. Key words: acetophenone, enolization, ketonization, keto–enol equilibrium, concentrated acid solutions.

scholarly journals Identification of Shorea species based on leaf morphological character with multivariate analysis

2021 ◽  
Vol 912 (1) ◽  
pp. 012084
Author(s):  
A B Rangkuti ◽  
A Susilowati ◽  
H Arinah ◽  
L Irmayanti ◽  
I Z Siregar ◽  
...  
Keyword(s):  
Multivariate Analysis ◽  
Principal Component ◽  
Strong Relationship ◽  
Statistical Technique ◽  
Shorea Species ◽  
The Tropics ◽  
Manova Analysis ◽  
High Degree ◽  
Shorea Leprosula ◽  
Degree Of Similarity

Abstract Shorea is one of the largest genera of the Dipterocarpaceae family that dominates Indonesian forests. This genus has an essential role in meeting the supply of wood, both at home and abroad. There are 194 species of shorea in the tropics. However, there is a high degree of similarity between one species and another, making it difficult to identify it. This study aims to estimate the variation of leaf morphology among 6 species of shorea at PT. Reki using multivariate analysis. Multivariate analysis is a statistical technique for analyzing data with a large number of variables. PCA (Principal component analysis), Biplot, and Manova were the three species of multivariate analysis used in this study. The results of PCA analysis showed that the variables of leaf elongation (PR), lamina length (PL) and leaf width to the base of the leaf (LP) had a strong relationship so that they could be used as a differentiator for the 6 shorea species. Biplot analysis showed that Shorea parvifolia, Shorea acuminata and Shorea leprosula had high similarities. It is also indicated by the leaves of the three species, which are more round in shape. The results of the Manova analysis showed a significant value <0.005, which means that all the variables tested have differences from one another. Shorea acuminata and Shorea leprosula have high similarity, and it is also indicated by the leaves of the three species, which are more round in shape.

Carbon protonation of some phenylynamines in concentrated aqueous perchloric acid solution. Lowering of the upper limit for the pKa of phenylynammonium ions

1996 ◽  
Vol 74 (7) ◽  
pp. 1373-1376 ◽  
Author(s):  
A.J. Kresge ◽  
S.W. Paine
Keyword(s):  
Acid Solution ◽  
Perchloric Acid ◽  
Rate Theory ◽  
Acidity Function ◽  
Perchloric Acid Solution ◽  
Hydronium Ion ◽  
Dilute Acid Solution ◽  
Saturated Compound ◽  
Initial States ◽  
Aqueous Perchloric Acid

Rates of carbon protonation of five phenylynamines (PhC≡CNH2, PhC≡CNHiPr, PhC=CNHC6F5, PhC≡CN(CH2CH2CN)2, and PhC≡CNMeC6F5) were determined in concentrated aqueous perchloric acid solution and the data were analyzed by the Cox–Yates method using the X0 acidity function. The extrapolated hydronium-ion catalytic coefficients so obtained are consistent with values measured directly in dilute acid solution, and the slopes of the Cox-Yates plots are similar to predictions made with the aid of Marcus rate theory for reactions originating from free ynamine initial states but unlike those predicted for reactions starting from nitrogen-protonated ynammonium ion initial states. This shows that none of these phenylynamines are protonated in even the most acidic solutions used (4 M) and sets new upper limits as low as pKa ≤ −3.1 for the conjugate acids of these ynamines. Comparison of the pKa limit for PhC≡CNH3+ with a literature value for the corresponding saturated compound, PhCH2CH2NH3+, gives a base-weakening effect for the phenylethynyl group of at least 12.5 pK units. Key words: acetylenic amines, concentrated acids, X0 excess acidity scale, Cox-Yates method, Marcus rate theory.

Participation of 19-substituents in electrophilic additions to 6,7-unsaturated 5α-cholestane and B-homo 5α-cholestane derivatives; A case of competition between the participation of an ambident neighboring group and external nucleophile attack

1980 ◽  
Vol 45 (2) ◽  
pp. 559-583 ◽  
Author(s):  
Pavel Kočovský ◽  
Ladislav Kohout ◽  
Václav Černý
Keyword(s):  
Perchloric Acid ◽  
Hydrobromic Acid ◽  
Cyclic Ether ◽  
Cyclic Ethers ◽  
Neighboring Group ◽  
Acid Cleavage ◽  
Neighbouring Group Participation ◽  
Aqueous Perchloric Acid ◽  
The Difference ◽  
Electrophilic Additions

Hypobromous acid action upon the 6,7-unsaturated 19-substituted 5α-cholestans Va-Vc results in the formation of two types of products, the cyclic ethers IX as products of 5(O)n participation of the 19-substituent, and the bromohydrins X. All these compounds are formed from the 6α,7α-bromonium ions Va'-Vc'. Under the same conditions the B-homo-5α-cholestane derivatives VIIa-VIIc afforded solely the cyclic ethers XIV as products of 5(O)n participation of the 19-substituent in the cleavage of the bromonium ions VIIa'-VIIc'. Acid cleavage of the 6α,7α-epoxides VIb and VIc with aqueous perchloric acid or hydrobromic acid gave two types of products, i.e. the cyclic ethers XI and the diols XII or bromohydrines XIII. The cyclic ethers XI arise by 5(O)n participation of the 19-substituent. The B-homo-6α, 7α-epoxide VIIIc on cleavage with aqueous perchloric acid have solely the cyclic ether XVc and by treatment with hydrobromic acid VIIIc afforded the mixture of XVc, as the main product, and of the bromohydrin XVIc. Discussed is the similarity of the bromonium ion cleavage with the fission of the corresponding epoxides, the mechanism of these reactions and the difference in the behaviour of the isomeric olefins Ia-c, IIIa-c, Va-c and VIIa-c and epoxides IIb,c, IVb,c, VIb,c and VIIIb,c. The competition between ambident neighbouring group participation and external nucleophile attack is discussed as well as the dependence of the products ratio on the nucleophilicity of the attacking species.

A psychologically-inspired fuzzy-based approach for user personality prediction in rumor propagation across social networks

2021 ◽  
pp. 1-15
Author(s):  
V. Indu ◽  
Sabu M. Thampi
Keyword(s):  
Social Networks ◽  
Factor Model ◽  
Five Factor Model ◽  
Principal Component ◽  
Common People ◽  
Rumor Propagation ◽  
Usage Patterns ◽  
User Personality ◽  
Personality Prediction ◽  
High Degree

Social networks have emerged as a fertile ground for the spread of rumors and misinformation in recent times. The increased rate of social networking owes to the popularity of social networks among the common people and user personality has been considered as a principal component in predicting individuals’ social media usage patterns. Several studies have been conducted to study the psychological factors influencing the social network usage of people but only a few works have explored the relationship between the user’s personality and their orientation to spread rumors. This research aims to investigate the effect of personality on rumor spread on social networks. In this work, we propose a psychologically-inspired fuzzy-based approach grounded on the Five-Factor Model of behavioral theory to analyze the behavior of people who are highly involved in rumor diffusion and categorize users into the susceptible and resistant group, based on their inclination towards rumor sharing. We conducted our experiments in almost 825 individuals who shared rumor tweets on Twitter related to five different events. Our study ratifies the truth that the personality traits of individuals play a significant role in rumor dissemination and the experimental results prove that users exhibiting a high degree of agreeableness trait are more engaged in rumor sharing activities and the users high in extraversion and openness trait restrain themselves from rumor propagation.

Using Cluster Analysis to Improve Marketing Experiments

1971 ◽  
Vol 8 (3) ◽  
pp. 340-347 ◽  
Author(s):  
George S. Day ◽  
Roger M. Heeler
Keyword(s):  
Cluster Analysis ◽  
Space Representation ◽  
Reduced Space ◽  
High Degree ◽  
Degree Of Similarity ◽  
Sensitive Experiment ◽  
Selection Of

When the selection of a sample of stores or cities requires a high degree of similarity among the test units in order to ensure a sensitive experiment, the sample may no longer represent the market. These conflicting requirements can be satisfied by choosing the sample from clusters displayed in a reduced space representation of the market.

15N N.M.R. Study of Some Palladium(II) Ammine Complexes

1988 ◽  
Vol 41 (9) ◽  
pp. 1425 ◽  
Author(s):  
TG Appleton ◽  
JR Hall ◽  
SF Ralph ◽  
CSM Thompson
Keyword(s):  
Perchloric Acid ◽  
Chemical Shifts ◽  
Free Ammonia ◽  
Silver Ion ◽  
Single Peak ◽  
Donor Atom ◽  
Ammine Complexes ◽  
Initial Product ◽  
Aqueous Perchloric Acid ◽  
Dimethylformamide Solution

Palladium(II) ammine complexes enriched in 15N give sharp singlets in their 15N n.m.r . spectra. The 15N chemical shifts depend primarily on the trans donor atom, in a qualitatively similar way to those for platinum(II) ammine complexes. A dimethylformamide solution of Pd(NH3)2Cl2 prepared in the usual way gave a single peak, consistent with the presence of only one isomer (trans). Reactions of increasing amounts of aqueous perchloric acid with Pd(NH3)42+ allowed peaks to be identified for Pd(NH3)3(H2O)2+, cis -Pd(NH3)2(H2O)22+ and Pd(NH3)(H2O)32+. The initial product of the reaction of trans-Pd(NH3)2Cl2 with silver ion is trans-Pd(NH3)2(H2O)22+, which rapidly disproportionates to Pd(NH3)3(H2O)2+ and Pd(NH3)(H2O)32+. With standing, subsequent reactions ultimately produce a solution containing predominantly cis -Pd(NH3)2(H2O)22+ in equilibrium with small amounts of the tri- and mono-ammine complexes, and free ammonia.

Are Tetranychus macfarlanei Baker & Pritchard and Tetranychus malaysiensis Ehara (Acari: Tetranychidae) one species? Morphological and molecular evidences for synonymy between these two spider mite species and a note on invasiveness of T. macfarlanei on okra and eggplant in India

2017 ◽  
Vol 22 (4) ◽  
pp. 467
Author(s):  
Mahran Zeity ◽  
Nagappa Srinivas ◽  
Chinnamade Channegowde Gowda
Keyword(s):  
Spider Mite ◽  
Morphological Characters ◽  
Molecular Data ◽  
Mite Species ◽  
Coi Gene ◽  
High Similarity ◽  
Mitochondrial Coi ◽  
Mitochondrial Coi Gene ◽  
High Degree ◽  
Degree Of Similarity

Study of morphological characters of Tetranychus macfarlanei Baker & Pritchard and Tetranychus malaysiensis Ehara revealed high similarity by comparing all the important characters in addition to the characters pointed out by Ehara to separate those two species. Molecular phylogeny of seven Indian populations of T. macfarlanei and one population of T. malaysiensis from Philippines along with few distantly related species of Tetranychus was attempted. High degree of similarity between these two species at mitochondrial COI gene (96%) as well as ITS2 (rDNA) (96–99%) region was evident. Based on both morphological features and molecular data, T. malaysiensis is proposed as a junior synonym of T. macfarlanei based on ICZN’s law of priority. Also more female characters are prompted in this study to distinctly discriminate T. macfarlanei from its most resembling species, Tetranychus ludeni Zacher. Tetranychus macfarlanei has emerged as a pest of several cultivated crop plants in India. 

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