Formaldehyde, reagents

Naphthoquinone-4-sulfonic Acid- Perchloric Acid - Formaldehyde Reagent... 

Naphthoquinone-4-sulfonic Acid-Perchloric Acid-Formaldehyde Reagent 353... 

Fluorophors 57 Fluphenazine 104 Fluram 294 Folic acid 223,225 Formaldehyde reagent 299, 351 -, vapor reagent 86 Formazan 220... 

Urea—formaldehyde and melamine—formaldehyde reagents are resin formers, which not only cross-link cotton but also copolymerize with themselves. These have been used both as simple cross-linkers or prepolymer systems. If too much of the polymerization is concentrated on the fiber surface, the fabric may be sufficiendy stiffer that it takes on a boardy character. As such, the finisher must control the action of agent to give the desired crisp hand but prevent the development of boardiness. Melamines have been recommended for applications when complete shrink resistance is required. However, both finishes were rejected for the white-shirt market because of loss of strength when hypochlorite bleach is used on account of vulnerable NH groups and the ensuing discoloration (37). 

Fluoromethyl ethers may additionally be attacked by a further alkene molecule under the reaction conditions, which then inserts between the C-F bond of the fluoromethyl group. Thus, 1,1-dihaloethene and the hydrogen fluoride/formaldehyde reagent react to form the symmetrical ether 6. 

Sample Preparation. The three primary resoles selected for inclusion in this study were synthesized in laboratory glassware in 4000 gram batches, using 99+% commercial phenol, ion-exchanged (low formic acid content) 50% aqueous formaldehyde, reagent grade 50% aqueous sodium hydroxide, and tap water. The three resins, coded A, B, and C, were allowed to react to the same apparent bulk viscosity as measured by the Gardner-Holdt bubble tube method. In addition to the same final viscosities, the resins also were synthesized from identical mole ratios F/P = 2.0, Na/P = 0.71. 

To each test tube, add 5 mL of the formaldehyde reagent. Mix by swirling and let it stand at room temperature for 30 min. 

The preparation of the o,p-phenol-formaldehyde reagent is described by Hirai [ 1 ]. In this preparation oxalic acid was used as the catalyst to ensure high ortho-para methylene content. 

Method. To 50 li1 of the sample add 1 ml of the Magenta Solution and 3 ml of Formaldehyde Reagent, and allow to stand for 5 minutes. At die same time, prepare a blank solution by adding 1 ml of Magenta Solution and 3 ml of water to 50 li1 of the sample. Record the absorbance of the first solution at 570 nm, using die second solution in die reference cell. 

Good regioselectivity is shown by the Mannich reaction on acetonyl theobromine, which exclusively gives the product 459, deriving from attack of the aminc/formaldehyde reagent on the methyl group of the acetonyl moiety.- ... 

Raymond and Smith 1988) from the same precursors used for the synthesis of the dibridged analog, but using a larger excess of the formaldehyde reagent and longer reflux time. The isolation and purification of the product were laborious and the yields quite low (3-5%). The structure of this compound was established primarily on the basis of fast-atom-bombardment (FAB) mass spectrometry. 

Tosylmethyl isocyanide provides a new masked formaldehyde reagent, which allows the alkylation of formaldehyde with an electrophilic reagent (Scheme 21). ... 

The above substitutes for the iodometric determination with one or two exceptions have not been tested for specificity for free SO2. Mathers (1949) on the basis of the fact that free sulfur dioxide is removed early in the distillation of wine proposed that 10 ml. of the distillate from the alcohol determination be mixed with 0.5 ml. of 5% neutral lead acetate and the turbidity of the suspension formed be used to correct volatile acidity for sulfur dioxide. La Rosa (1950) assumed that the color formed on mixing the fuchsin-sulfuric acid-formaldehyde reagent with white wine was a measure of free SO2 but did not give any data to confirm this. The fuchsin procedure and the lead sulfite procedures are very sensitive, the former more so, and can be applied only to very small aliquots or to dilute solutions. 

Foerster transfer rate, columnar discotics 790 formaldehyde, reagents 716 formulations, chiral nematics 305 fourth rank tensor, ferroelectrics 614 frame rate control. Gray levels 207 frame time, TN displays 205 Frank constants... 

ToUen s ammoniacal sih er nitrate, although not specific, is a sensith e formaldehyde reagent possessing a sensitiAuty of about 2 ppm under optimum conditions. 

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