903. A study of the borate–carbohydrate complex

Malcolm, Earl W.; Green, John W.; Swenson, Harold A.

doi:10.1039/jr9640004669

Cited by 14 publications

(7 citation statements)

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“…Complex formation of borate salts and boric acid with carbohydrate polymers has been known for years (77). Monoand dicomplex formations were shown with galactosides and mannosides (7). Carbohydrate-borate complexes usually manifest a gel-stiffening effect similar to that shown above, but an essential feature of these complexes is that the carbohydrate material contains adjacent cff-hydroxyl groups (7).…”

Section: Discussionmentioning

confidence: 68%

Colloidal Oxycellulose by Nitrogen Dioxide Treatment of Level-Off Degree of Polymerization Cellulose

Belfort¹,

Wortz²

1966

I&EC Product Research and Development

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Section: Discussionmentioning

confidence: 68%

Colloidal Oxycellulose by Nitrogen Dioxide Treatment of Level-Off Degree of Polymerization Cellulose

Belfort¹,

Wortz²

1966

I&EC Product Research and Development

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“…However the linewidth of the 23Na signal for a solution of boric acid (0.1 rnol dm-3), D-glucaric acid (0.1 rnol dm-'), and NaCl (3.0 rnol dm-3) at pH 10.0 was ca. 30 Hz, which suggests that the average state of the Na' ions differs from the free hydrated form (8 Hz). Sodium co-ordination does not interfere with the Ca" co-ordination as the linewidth did not change upon Ca" addition.…”

Section: Resultsmentioning

confidence: 99%

Studies on borate, esters. Part 8. Interactions of cations with oxyacid anion-bridged esters of D-glucarate in alkaline media

Duin¹,

Peters²,

Kieboom³

et al. 1987

J. Chem. Soc., Dalton Trans.

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Cation co-ordination has been studied in aqueous cation-borate-D-glucarate systems using "B n.m.r. spectroscopy. The univalent cations K1, Nal, and Agl do not show preferential co-ordination by the borate esters of D-glucarate. The divalent cations Mg", Call, Coil, Nil1, Sr", C d Y and Ball are co-ordinated by the borate diesters. The cations that ionize the a-hydroxyl functions of Dglucarate, Cull, Zn", Prlll, and Pb", and/or compete with borate for the diol functions, and Fell1, are more strongly co-ordinated by free o-glucarate than by its borate diester. The different behaviour of the cations is discussed in terms of differences in charge/radius density and polarizing ability. In the CaI I-oxyacid anion-o-glucarate system, Call ion-selective electrode measurements and CaI I sequestering capacity determinations have been performed. Apart from borate, synergic Call co-ordination is observed at high p H for the oxyacid anion esters of D-glucarate of antimonite, stannate, aluminate, and germanate.Aqueous alkaline solutions of borate and polyhydroxycarboxylates possess good cation sequestering abilities and are applied in the galvanic, glass, and cement industries, and in pharmaceutical^.^ In addition, these systems have potential as triphosphate substitutes in detergent^.^,^ We have determined the stability and structure of borate mono-and di-esters of a series of polyhydroxycarboxylates (Figure 1) using multinuclear n.m.r. ~p e c t r o s c o p y . ~* ~The synergic Ca" co-ordination in these systems finds its origin in the high Ca" co-ordinating strength of the borate diesters of the polyhydroxycarboxylates.2-8 This effect is most pronounced for D-glucarate (Figure 2) as the polyhydroxy~arboxylate.~~~~~ Formation of the threo-3,4borate diesters of D-glucarate results in the creation of new multidentate Ca" co-ordinating sites.' Each of these sites is composed of two carboxylate oxygens, two borate ester ring oxygens, and, depending on the configuration, up to two hydroxyl oxygens (Figure 3).2*8 Borate (B"') is not unique in forming oxyacid anion esters (or complexes) with diol functions. Other oxyacid anions (X -) such as aluminate (Al"'), silicate (Si"), germanate (Gel'), arsenite (As"'), selenite (SeIV), stannate (Sn"), antimonate (Sb'), tellurate (Te"), and periodiate (Iv") are also capable of doing

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“…Später wurde vorgeschlagen, dass ein Borsäureester nebeneinanderliegende Moleküle oder Stränge, von z. B. Galactomannan-Polysacchariden, verbrücken kann [7] (Abb. 2).…”

Section: Polysaccharid-metallkomplexeunclassified

New Slime

Brink¹,

Hubricht²

2014

Chemkon

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Zusammenfassung: Infolge der Richtlinie 2008/58/EG der europäischen Kommission wurden Dinatriumtetraborate, welche für das beliebte "Slime-Experiment" verwendet werden, hinsichtlich ihres Gefahrenpotenzials neu eingestuft. Als Folge der Neueinstufung entstand eine Unsicherheit bei den Lehrkräften gegenüber dem Einsatz dieses Versuchs. Teilweise wurden zudem offiziell Empfehlungen ausgesprochen, das "Slime-Experiment" mit Dinatriumtetraboraten nicht mehr durchzuführen. In "New Slime" gelingt die Vernetzung der Galactomannan-Polysaccharidketten mithilfe eines unbedenklichen Aluminiumsalzes. Im geeigneten pH-Wertbereich entsteht durch die Zugabe von Aluminium-Ionen aus einer weißen viskosen Flüssigkeit ein hellgelber "Slime", der sich ähnlich wie der bekannte Borax-Schleim verhält. Die Fachliteraturrecherche liefert Indizien dafür, dass in Abhängigkeit von dem pH-Wert Aluminium-Ionen von sterisch geeigneten, deprotonierten Hydroxylgruppen des Galactomannan-Polysaccharids komplexiert werden kçnnen. Experimentell untermauert wird diese Hypothese in unseren Untersuchungen durch die Reaktion von "New Slime" mit Citrat-Ionen.Stichworte: Alternative Schulversuche · Komplexchemie · New Slime "New Slime": polysaccharide-metal-complexes instead of boron-linked guar gum Abstract: The reclassification of disodiumtetraborates in the current version of the European guidelines (2008/ 58/EG) had changed the consideration of the "Slime Experiment". There is uncertainty at schools and partially the recommendation to avoid that experiment in chemistry education and at primary schools. With "New Slime" the crosslink of galactomannan polymers succeeds by means of aluminium salt. According to literature research, the dependency of pH value and the observed behaviour to complexing citric acid it is assumed, that aluminium ions are coordinated by steric suited, deprotonated hydroxyl groups of the galactomannan building blocks. Thus, a clear white viscous liquid changes into a yellow viscoelastic "Slime", which moves similar to the well-known boron-slime.

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903. A study of the borate–carbohydrate complex

Cited by 14 publications

References 0 publications

Colloidal Oxycellulose by Nitrogen Dioxide Treatment of Level-Off Degree of Polymerization Cellulose

Colloidal Oxycellulose by Nitrogen Dioxide Treatment of Level-Off Degree of Polymerization Cellulose

Studies on borate, esters. Part 8. Interactions of cations with oxyacid anion-bridged esters of D-glucarate in alkaline media

New Slime

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