Elucidation of the steps selected for the production of haemostatic, wound healing and absorbable... more Elucidation of the steps selected for the production of haemostatic, wound healing and absorbable polyglucuronic acid, as well as of the mechanism of its alkali solubility is the target of the present work. During the reaction of cellulose with NO 2 , the process arrives at equilibrium prior to the expected degree of oxidation, which is due to the competitive adsorption of N 2 O 3 on the cellulose surface, thus preventing the access of the oxidising agent (N 2 O 4 2NO 2 ) from the surrounding area. Raising the temperature of the system brings about desorption of N 2 O 3 and offers free access of the oxidising agent, resulting in further oxidation of cellulose. The generated accessible sites will be occupied by the N 2 O 4 2NO 2 molecules present in the systems, which enable further oxidation of cellulose. Resolution of the polyglucuronic acid in slightly alkaline blood and humour might be attributed not only to its high carboxyl content, but also to a secondary chemical reaction ind...
Homolog mixture of basic molecules of cucurbiturils has been synthesized and cucurbit[6]uril (CU[... more Homolog mixture of basic molecules of cucurbiturils has been synthesized and cucurbit[6]uril (CU[6]) and cucurbit[8]uril (CU[8]) have been isolated by means of solvent extraction. Inclusion complexes of different acid, reactive and disperse dyes have been produced by them. CU[8] was decidedly more efficient in complex formation with all the studied dyes than CU[6]. Competitive complex formation between randomly methylated ß-cyclodextrin and the respective cucurbiturils with disperse dyes has been studied and superiority of CU[8] could be demonstrated. The complex forming efficiency of the cucurbiturils with acid and reactive dyes was markedly increased in the presence of Ca, Mg, K and Na ions, respectively, in water solution.
Two heterobifunctional reactive azo dyes (A(MCT-VS), (B(MCT-VS)) as well as their partly and full... more Two heterobifunctional reactive azo dyes (A(MCT-VS), (B(MCT-VS)) as well as their partly and fully hydrolysed derivatives and their ''naked chromophores'' have been used in preparing cellulosic dyeings. Reactive (RC) and substantive (N) dyeing procedures have been used, respectively. Two sets of dyeings (5 pieces each) have been produced as members of the A group and those of the B group. All dyeings have been exposed to light of Xenotest 450 equipment for 96 h in open and in closed air as well as in closed oxygen and closed nitrogen atmospheres, respectively. Similar exposures have been performed also in the presence of artificial perspiration prepared according to Japanese standard (pH Z 3.5). The light stability of all dyeings of the A group exceeded that of the respective values of the members of the B group under exposure to light in open air atmosphere in the absence of perspiration. In the presence of perspiration, however, all members of the B group proved to be more stable to light than the respective members of the A group. It could be concluded that the members of the A group proved to be less sensitive to oxidative photofading than those of the B group whereas the sensitivity to reductive photofading was definitely higher in A dyeings. The observed rather contradictory behaviour between the A and B groups of similar chemical structure might be attributed to the Hammett effect of the electron donating methoxy substituent in the B structures.
The accuracy in the determination of the fixed proportion of two hetero bi-functional reactive az... more The accuracy in the determination of the fixed proportion of two hetero bi-functional reactive azo-dyes on cotton cellulose was studied in the present paper. One direct and two indirect (indirect I and indirect II) analytical methods were used in the experiments. ANOVA (Analysis of Variance) statistical method was used to evaluate the precision of the measurements. The most reliable results could be achieved by using the indirect I method, while the indirect II method was much inferior. The use of direct method, being definitely more complicated than any of the indirect ones, produced least accuracy. Keywords analytical methods ANOVA • evaluation dye content • reactive dyeing reliability Acknowledgement Authors are obliged to thank Sumitomo Chemical Co Ltd (Japan) for kind cooperation in offering the studied dyes.
Elucidation of the steps selected for the production of haemostatic, wound healing and absorbable... more Elucidation of the steps selected for the production of haemostatic, wound healing and absorbable polyglucuronic acid, as well as of the mechanism of its alkali solubility is the target of the present work. During the reaction of cellulose with NO 2 , the process arrives at equilibrium prior to the expected degree of oxidation, which is due to the competitive adsorption of N 2 O 3 on the cellulose surface, thus preventing the access of the oxidising agent (N 2 O 4 2NO 2 ) from the surrounding area. Raising the temperature of the system brings about desorption of N 2 O 3 and offers free access of the oxidising agent, resulting in further oxidation of cellulose. The generated accessible sites will be occupied by the N 2 O 4 2NO 2 molecules present in the systems, which enable further oxidation of cellulose. Resolution of the polyglucuronic acid in slightly alkaline blood and humour might be attributed not only to its high carboxyl content, but also to a secondary chemical reaction ind...
Homolog mixture of basic molecules of cucurbiturils has been synthesized and cucurbit[6]uril (CU[... more Homolog mixture of basic molecules of cucurbiturils has been synthesized and cucurbit[6]uril (CU[6]) and cucurbit[8]uril (CU[8]) have been isolated by means of solvent extraction. Inclusion complexes of different acid, reactive and disperse dyes have been produced by them. CU[8] was decidedly more efficient in complex formation with all the studied dyes than CU[6]. Competitive complex formation between randomly methylated ß-cyclodextrin and the respective cucurbiturils with disperse dyes has been studied and superiority of CU[8] could be demonstrated. The complex forming efficiency of the cucurbiturils with acid and reactive dyes was markedly increased in the presence of Ca, Mg, K and Na ions, respectively, in water solution.
Two heterobifunctional reactive azo dyes (A(MCT-VS), (B(MCT-VS)) as well as their partly and full... more Two heterobifunctional reactive azo dyes (A(MCT-VS), (B(MCT-VS)) as well as their partly and fully hydrolysed derivatives and their ''naked chromophores'' have been used in preparing cellulosic dyeings. Reactive (RC) and substantive (N) dyeing procedures have been used, respectively. Two sets of dyeings (5 pieces each) have been produced as members of the A group and those of the B group. All dyeings have been exposed to light of Xenotest 450 equipment for 96 h in open and in closed air as well as in closed oxygen and closed nitrogen atmospheres, respectively. Similar exposures have been performed also in the presence of artificial perspiration prepared according to Japanese standard (pH Z 3.5). The light stability of all dyeings of the A group exceeded that of the respective values of the members of the B group under exposure to light in open air atmosphere in the absence of perspiration. In the presence of perspiration, however, all members of the B group proved to be more stable to light than the respective members of the A group. It could be concluded that the members of the A group proved to be less sensitive to oxidative photofading than those of the B group whereas the sensitivity to reductive photofading was definitely higher in A dyeings. The observed rather contradictory behaviour between the A and B groups of similar chemical structure might be attributed to the Hammett effect of the electron donating methoxy substituent in the B structures.
The accuracy in the determination of the fixed proportion of two hetero bi-functional reactive az... more The accuracy in the determination of the fixed proportion of two hetero bi-functional reactive azo-dyes on cotton cellulose was studied in the present paper. One direct and two indirect (indirect I and indirect II) analytical methods were used in the experiments. ANOVA (Analysis of Variance) statistical method was used to evaluate the precision of the measurements. The most reliable results could be achieved by using the indirect I method, while the indirect II method was much inferior. The use of direct method, being definitely more complicated than any of the indirect ones, produced least accuracy. Keywords analytical methods ANOVA • evaluation dye content • reactive dyeing reliability Acknowledgement Authors are obliged to thank Sumitomo Chemical Co Ltd (Japan) for kind cooperation in offering the studied dyes.
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