Color Reactions of Rubber and Gutta-Percha

1930 ◽  
Vol 3 (1) ◽  
pp. 22-23
Author(s):  
F. Kirchhof
Keyword(s):  
Carbon Tetrachloride ◽  
Absorption Spectra ◽  
Aluminum Chloride ◽  
Point Of View ◽  
Previous Article ◽  
Reaction Products ◽  
Characteristic Absorption ◽  
Iron Aluminum ◽  
Gutta Percha ◽  
Color Reactions

Abstract A previous article of mine entitled “Observations on Color Reactions of Rubber and Gutta-Percha” has led to the question whether intensely colored reaction products which are obtained by fusion of phenols with bromides of hydrocarbons give characteristic absorption spectra. I have carried out a few preliminary experiments on this subject, which appear to confirm my earlier point of view that the cause of the different colorations is to be found in dispersion color reactions. It is well known that when rubber bromide or gutta-percha bromide is suspended in carbon tetrachloride and is heated with phenol until the carbon tetrachloride is eliminated, a red-violet to blue fusion mixture is obtained, which gives colors of various stabilities depending upon the solvent into which the fusion mixture is dropped. Thus the blue and violet colorations in chloroform are stable for some time, but they change gradually to green and then to brown, with separation of a flocculent precipitate. Yellow-brown reaction products (hydroxyphenylhydrorubber and gutta-percha) are however obtained in the presence of catalysts (iron, aluminum chloride) or by the action of alkalies (NH3, KOH) or by pouring the blue-violet fusion mixtures into ether.

ULTRAVIOLET ABSORPTION SPECTRA AND ACIDITIES OF ISOMERIC THIATRIAZOLE AND TETRAZOLE DERIVATIVES

1959 ◽  
Vol 37 (3) ◽  
pp. 563-574 ◽  
Author(s):  
Eugene Lieber ◽  
J. Ramachandran ◽  
C. N. R. Rao ◽  
C. N. Pillai
Keyword(s):  
Absorption Spectra ◽  
Absorption Maximum ◽  
Dipole Moments ◽  
Ring System ◽  
Ultraviolet Absorption ◽  
Characteristic Absorption ◽  
Tetrazole Derivatives

The ultraviolet absorption spectra of 5-(substituted)amino-1,2,3,4-thiatriazoles and the corresponding isomeric 1-substituted-tetrazoline-5-thiones have been studied. The spectra and the dipole moments of the 5-(substituted)amino-1,2,3,4-thiatriazoles eliminate the possibility of meso-ionic structures for these compounds. The dipole moments of 5-amino-, 5-methylamino-, and 5-dimethylamino-1,2,3,4-thiatriazole were all high but approximately of the same value (5.77 to 5.84 D). This suggests that the amino thiatriazoles are best represented by conventional covalent structures with significant ionic resonance contributions. The thiatriazole ring system exhibits a characteristic absorption maximum at 250–255 mμ and an electron-withdrawing effect approximately equal to the tetrazolyl ring system. The tetrazolinethionolyl ring system is similarly electron-withdrawing. The relative acidities of the 1-substituted-tetrazoline-5-thiones and the 5-alkylmercaptotetrazoles have also been studied and the results support the observations made on the basis of their ultraviolet absorption spectra.

Sulfur Linkage in Vulcanized Rubber. Reaction of Methyl Iodide with Sulfur Compounds

1949 ◽  
Vol 22 (1) ◽  
pp. 1-7
Author(s):  
M. L. Selker
Keyword(s):  
Methyl Iodide ◽  
Room Temperature ◽  
Sulfur Compounds ◽  
Point Of View ◽  
Secondary Reaction ◽  
Reaction Products ◽  
Sulfide Sulfur ◽  
Vulcanized Rubber ◽  
Allyl Sulfide

Abstract The work described here is an extension of the study of the reaction of methyl iodide with sulfur compounds originally begun with the purpose of using such data in determining the sulfur linkage in vulcanized rubber. A previous paper dealt with the reactions of methyl iodide with propanethiol, propyl sulfide, propyl disulfide, allyl sulfide, and thiophene. This article adds to the list, n-butyl methallyl sulfide, allyl disulfide, allyl tetrasulfide, n-propyl tetrasulfide, and trithiane. The removal of combined sulfur from vulcanized rubber as trimethylsulfonium iodide on treatment with methyl iodide at room temperature was persuasive evidence of the presence of sulfide sulfur linked to allylic type residues. The evidence offered, however, did not constitute exclusive proof because it was not known whether still other types of sulfur linkage would also yield trimethylsulfonium iodide. To shed more light on this question, the sulfur linkages most likely to occur in vulcanizates—the allyl-alkyl monosulfide, diallyl and dialkyl di- and polysulfide—were investigated. The trithiane reaction is of interest mostly from the point of view of the reaction of overcured stocks or secondary reaction products stemming from the original polysulfides. The reactions were carried out using the method described in a previous paper.

scholarly journals Occurrence of Furosine and Hydroxymethylfurfural in Breakfast Cereals. Evolution of the Spanish Market from 2006 to 2018

Foods ◽  
2019 ◽  
Vol 8 (5) ◽  
pp. 158 ◽  
Author(s):  
Marta Mesías ◽  
Laura Sáez-Escudero ◽  
Francisco J. Morales ◽  
Cristina Delgado-Andrade
Keyword(s):  
Manufacturing Process ◽  
Protein Quality ◽  
Sugar Content ◽  
Point Of View ◽  
Maillard Reaction Products ◽  
Reaction Products ◽  
Breakfast Cereal ◽  
Breakfast Cereals ◽  
Damage Indices ◽  
Amadori Compounds

The demand for healthier products has led the breakfast cereal sector to develop new formulations to improve the nutritional profile of breakfast cereals; however, the increase in chemical risks should also be evaluated. Amadori compounds and 5-hydroxymethylfurfural (HMF) are Maillard reaction products applied as heat damage indices in breakfast cereals. Furosine (a synthetic amino acid formed by acid hydrolysis of Amadori compounds) is linked to the loss of protein quality, while HMF has exhibited toxicological effects in cells and animals. Furosine and HMF content was evaluated in Spanish breakfast cereals whereas the effect of protein, fibre, and sugar content, the type of grain, the presence of honey, and the manufacturing process were discussed, as well as compared with a previous prospective study. The average furosine and HMF contents were 182 mg/kg and 21.7 mg/kg, respectively. Protein and fibre content were directly related to the furosine content, whereas sugar level, honey addition, and the manufacturing process affected the content of HMF. Occurrence of furosine and HMF decreased nearly 40% in a decade (2006–2018). These findings are relevant in terms of nutritional score, since lysine availability is preserved, but also from a toxicological point of view, due to the decreased daily exposure to both compounds, which dropped 30%.

scholarly journals The absorption spectra of halogens and inter-halogen compounds in solution in carbon tetrachloride

1929 ◽  
Vol 124 (795) ◽  
pp. 604-616 ◽  
Keyword(s):  
Absorption Spectrum ◽  
Carbon Tetrachloride ◽  
Absorption Spectra ◽  
Spectroscopic Data ◽  
Chemical Interaction ◽  
Chemical Compounds ◽  
Absorption Bands ◽  
Halogen Compounds ◽  
Inert Solvent ◽  
The Mean

When two solutions are mixed the absorption spectrum of the new solution will be the mean of those of the separate solutions provided that no chemical interaction occures. The mere fact of a departure from additivity does not, however, necessarily denote the formation of true chemical compounds. The solute or solutes may undergo solvation, loosely bound aggregates may occur, and even when marked deviations from the simple law of mixtures are observed it is rarely possible to prove the quantitative formation of a given chemical compound from spectroscopic data alone. The above considerations apply with some force to the problem of the absorption spectra of halogens and inter-halogen compounds in an inert solvent. The three elements show perfectly characteristic absorption bands, they are known to interact with the formation of some quite stable compounds, some relatively stable compounds, and some apparently very unstable compounds.

The Quality of Brazed Ceramic and Cemented Carbide Joints - A Mechanical and Metallurgical Assessment

2010 ◽  
Vol 64 ◽  
pp. 108-114 ◽  
Author(s):  
Wolfgang Tillmann ◽  
Lukas Wojarski ◽  
Benjamin Lehmert
Keyword(s):  
Thermal Stresses ◽  
Mechanical Performance ◽  
Ceramic Materials ◽  
Mechanical Tests ◽  
Point Of View ◽  
Cemented Carbides ◽  
Full Potential ◽  
Ceramic Surface ◽  
Reaction Products

The availability of adequate joining technologies is of major importance in order to exploit the full potential of ceramic materials. The same is true for joints between cemented carbides and their counterparts. Such joints are not easy to manufacture due to wetting and bonding problems as well as induced thermal stresses. Currently, active brazing is a potential approach for fabricating such joints. The filler alloy contains reactive agents such as Titanium or Hafnium etc. that interact by forming wettable reaction layers on the ceramic surface. It is self-evident that they function very well on cemented carbides as well. The paper describes potential wetting and bonding reactions from a metallurgical point of view. Ceramics, superabrasive and cemented carbides are investigated with respect to interfacial reactions. The quality of the reaction products is of crucial importance regarding the mechanical performance of the joints, as their immanent brittleness can lead to a significant weakening. Apart from metallurgical assessments, mechanical tests are conducted in order to deliver data for their integration in hybrid structures. FE methods can be applied to assess the stress situation in the final joint. Thus it is possible to adjust the design accordingly.

scholarly journals Unification Theories: New Results and Examples

Axioms ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 60 ◽  
Author(s):  
Florin F. Nichita
Keyword(s):  
Type Equation ◽  
Point Of View ◽  
Previous Article ◽  
Associative Algebras ◽  
Hyperbolic Functions ◽  
Euler’S Formula

This paper is a continuation of a previous article that appeared in AXIOMS in 2018. A Euler’s formula for hyperbolic functions is considered a consequence of a unifying point of view. Then, the unification of Jordan, Lie, and associative algebras is revisited. We also explain that derivations and co-derivations can be unified. Finally, we consider a “modified” Yang–Baxter type equation, which unifies several problems in mathematics.

Rapid Infrared Method for Toxaphene in Animal Dips and Sprays

1964 ◽  
Vol 47 (3) ◽  
pp. 591-594
Author(s):  
Fred P Czech
Keyword(s):  
Sodium Chloride ◽  
Carbon Tetrachloride ◽  
Infrared Spectrum ◽  
Spectrophotometric Method ◽  
Active Ingredient ◽  
Baseline Method ◽  
Characteristic Absorption ◽  
Characteristic Absorption Peak ◽  
Infrared Method

Abstract An infrared spectrophotometric method has been developed for the determination of toxaphene in aqueous emulsions used for the eradication of ectoparasites in livestock. The active ingredient is "salted-out" of emulsion with sodium chloride and extracted with carbon tetrachloride, and an infrared spectrum is taken of the latter extract. Toxaphene concentration is obtained from its characteristic absorption peak at 1303 cm-1 by the baseline method. The infrared method has the advantages of speed, simplicity, and, especially, specificity over chemical procedures.

scholarly journals Beroep op die skrif in die vorm van etiese standpunte, Deel 2: ’n Etiese verstaan van die vrou in die Bybel

2012 ◽  
Vol 46 (2) ◽  
Author(s):  
Adriaan L. Rheeder
Keyword(s):  
Point Of View ◽  
Previous Article ◽  
Empirical Knowledge ◽  
Theological Interpretation ◽  
Historical Method ◽  
Women In The Bible ◽  
The Bible ◽  
Ethical Point ◽  
Point Of Departure ◽  
The Church

In ’n vorige artikel is beredeneer dat die grammaties-historiese metode van Skrifuitleg as kreatuurlike geskrif nie meer voldoende is vir alleengebruik in Skrifvertolking nie en dat dit met ander uitgangspunte aangevul moet word. In aansluiting by twee hermeneutiese uitgangspunte wat in ’n vorige artikel behandel is (Rheeder), word in hierdie artikel ’n verdere drie hermeneutiese vertrekpunte bespreek, naamlik teenkultuur, nie-wetenskaplike skopus en moreel-etiese vertolking. Die teenkulturele vertrekpunt gaan uit van die oortuiging dat outentieke getuienis in die Skrif gevind word in dit wat verskil (afwyk) van die omliggende antieke kultuur, terwyl die nie-wetenskaplike skopus vertrekpunt uit gaan van die standpunt dat wetenskaplike (of empiriese) kennis in die Bybel buite die skopus of bedoeling van die Skrif staan. Die moreel-teologiese vertolking as vertrekpunt van die standpunt uitgaan dat ’n moreel-teologiese beoordeling van liefde die keuse tussen twee konflikterende, maar beide aanvaarbare, interpretasies moet begelei. Daar word tot die gevolgtrekking gekom dat ’n etiese verstaan van die posisie van die vrou beteken dat die vrou as gelykwaardig aan die man beskou en so behandel moet word, wat beteken dat die vrou, net soos die man, tot enige amp in die kerk toegelaat mag word.Appeal to Scriptures in the formation of an ethical point of view: An ethical understanding of women in the Bible. In a previous article it was argued that the grammatical-historical method  of  Bible  exposition  was  no  longer  sufficient  as  sole  method  and  should  be supplemented with other hermeneutical points of departure. Following the discussion of two hermeneutical points in a previous article (Rheeder), this article will discuss three other hermeneutical points of departure, namely counterculture, non-scientific scope and moral-ethical interpretation. The counter-cultural point of departure is based on the belief that authentic witness in Scripture is found in that which is different (that which deviates) from the surrounding ancient culture, while a non-scientific scope starts from the view that scientific (or empirical) knowledge in the Bible is outside the scope or intent of Scripture. The point of departure of the moral-theological interpretation is the view that a moral-theological evaluation of love should inform the choice between two conflicting but mutually acceptable interpretations. It is concluded that an ethical understanding of women in the Bible means that women should be regarded and treated as equal to men, which leads to the further conclusion that all offices in the church should be open to women.

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