Reduction clearing

Afterscouring of polyester generally includes a reduction clearing with sodium hydrosulfite and alkaH at 60—80°C to remove any dye remaining on... 

Nonetheless, the reduction clearly proceeds by initial addition of one electroi to the aj omatic ring and the resulting radical-anion must be protonated ii some way before the second electron addition can occur. 

Subsequently, Paquette and Johnson used LAH reductions to convert strained thietane or thiolane derivatives to their respective sulphides, generally in good yields. Whitney and Cram described the LAH reduction of a chiral derivative of benzothiophene sulphone, as outlined in equation (24). The authors also noted the formation of hydrogen gas and suggested that their results were consistent with those of Bordwell as outlined in equation (22), namely that reduction takes place by the formation of an aluminium oxide and hydrogen gas. In this case, the reduction clearly cannot involve the formation of an a-sulphonyl carbanion and it is unlikely that any C—S bond cleavage and reformation could have occurred. 

The change of the initial state energy of the silver core levels during size reduction clearly suggests that there should be size dependent changes in the valence band DOS of the Ag nanoparticles, which can be visualized by valence band XPS and UPS measurements. 

Table 12.10 Fastness of black polyester dyeings after various reduction clearing treatments [123]...

In fact thermomigration readily takes place in the absence of surfactant, albeit usually to a lesser extent. In this case only the second of the above processes takes place. The term surfactant in this model can be interpreted broadly to include any residual surfactant, reduction clearing assistant or applied finish, such as an antistat, lubricant or softener. 

For polyester, the washing-off process to remove unfixed dye and thickening agent is generally a reduction clear as described in section 12.6.6. A simple wash-off with nonionic surfactant must be used on cellulose acetate or triacetate, although a mild reduction clear may be preferable on triacetate. 

Known properties of the delta function were used in this reduction. Clearly, the impulse input is delayed at the outlet by the period of the residence time. 

For some models adsorption or storage is important. For example, oxygen storage is important in a 3-way catalysis, a catalyst may contain a hydrocarbon storage component for improved low-temperature performance, and ammonia storage is important for ammonia SCR (selective catalytic reduction). Clearly, this sort of behaviour needs to be included in the final model. The nature of the measurements depends on the exact system being studied and will be discussed in more detail later. Suffice to say, from measurements at steady state, the heats of adsorption and coefficients of... 

The resulting flood of data required more and more reduction, clear representation (in the sense of visualization), and extraction of the relevant information. This abundance of data also provided the possibility of more detailed and quantitative description of reaction mechanisms and structure-activity relationships. 

Subsequent research was directed toward reuse of both the dyebath and the sodium hydrosulfite/sodium hydroxide reduction clearing bath utilized by the participating plant. Both... 

Reactive dyes will not color polyester, and thus the conventional process for dyeing blends consists of four distinct and separate procedures dyeing of the polyester with disperse dyes, reduction/clearing of the polyester, impregnation of the cotton component with reactive dyes, and fixation of the reactive dye. 

The reduction of [Fe3 ( 3-S)2 (CO)g (tSCHCHli) ] in DMF is reversible at fast cyclic voltammetric sweep rates ( = -0.73 V). In the presence of P(OMe)3, three new reduction waves are observed, revealing the stepwise substitution of carbonyl ligands to give [Fe3(/X3-S)2(CO)8 P(OMe)3 (< SCHCHS)] n = 1-3). Under 1 atm carbon monoxide, the rate of substitution was less, leading thd authors to favor a mechanism involving CO displacement after the initial reduction step, rather than rupture of the M—M bond before ligand loss. In either case, reduction clearly activates the cluster toward carbonyl substitution 150). 

Anders S and Schindler W, Comparison of reducing agents in reduction clearing of polyester dyeings and prints , Melliand Textilberichte, 1997, 78, 85-87, E21-E22. 

Recommended for use in kier boiling, bleaching vat dyeing and reduction clearing. Relatively low foaming. 

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