TBAF/DMSO

Fischer titration may not be reliable for water concentration determination in the presence of highly hygroscopic electrolytes, e.g., LiCl/DMAc [119]. This conclusion has been also verified for TBAF/DMSO, by adding known amounts of water to the solvent system, followed by determination of the water content by Karl-Fischer titration. Whereas the added water ranged from 0.23 to 1.19 mol H, that determined by titration ranged from 0.21 to... 

Scheme 34. Reagents and conditions (a) Et2NH, EtsN, 10mol% tetrabutyl ammonium fluoride (TBAF), DMSO, 70°C (b) PhLi, THF, -78°C (c) 10% HCI aq rt.

Advances of the past three decades, however, have produced alternatives to the heavy metal-based cellulose solvents. Prominent among them are dimethylacetamide/LiCl (DMAc/LiCl) N,MMN-0 hydrate (NMMO) tetrabutylammonium fluoride/DMSO (TBAF/DMSO) and potassium thiocyanate/DMSO [48]. While many of these solvents have gained significant popularity among laboratory chemists, only the amine oxide solvent, N,MMNO, has achieved industrial practicality. This will be discussed in the section on regenerated cellulose fibers. Several other important physical properties of cellulose are given in O Table 4. 

Reaction of dioxetane la and 2 initiated by addition of TBAF/DMSO In a representative case, 0.3 mg of la was dissolved in ca. 10 xL of DMSO and the reaction initiated by addition of 10 pL of 1 M TBAF/DMSO solution at room temperature. 

In the case of the reaction of dioxetanes la and 2 initiated by addition of TBAF/DMSO, significant differences in heat evolution were observed in the comparison between reactions in a coated quartz cell and in a transparent cell. The quantum yield of chemiluminescence measured by Schaap et al., for la is 0.25 which is high enough to measure difference in reaction heat between reactions in a coated quartz cell (Q5, Q6) and a transparent cell (Q7, Q8). The reaction heat differences measured for the coated and transparent cells by DSC method, AEl = Q5 - Q6 = 6.6 kcal/mol and AE2 = Q6 - Q7 = 5.5 kcal/mol represented the amount of reaction heat... 

Ostlund A, Lundberg D, Nordstiema L, Holmberg K, Nyden M (2009) Dissolution and gelation of cellulose in TBAF/DMSO solutions the roles of fluoride ions and water. Biomacromolecules 10 2401-2407... 

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