P-Phenylenediamine developer

Developer 13, see p-Phenylenediamine Developer P, see 4-Nitroaniline Developer PF, see p-Phenylenediamine Devicarb, see Carbaryl Devikol, see Dichlorvos Devol orange B, see 2-Nitroaniline Devol orange R, see 3-Nitroaniline Devol orange salt B, see 2-Nitroaniline Devol red GG, see 4-Nitroaniline Devoran, see Lindane Devoton, see Methyl acetate Diacetone, see Diacetone alcohol Diacetonyl alcohol, see Diacetone alcohol Diakon, see Methyl methacrylate Dialene 6, see 1-Hexene 1,4-Diaminobenzene, see p-Phenylenediamine p-Diaminobenzene, see p-Phenylenediamine 4-Diaminodiphenyl, see Benzidine p-Diaminodiphenyl, see Benzidine 4,4 Diaminobiphenyl, see Benzidine p,p -Diaminobiphenyl, see Benzidine 4,4 -Diamino-l,l -biphenyl, see Benzidine 4,4 -Diamino-3,3 -dichlorobiphenyl, see 3,3 -Dichloro-benzidine... 

Silver catalysis of the reduction of silver ions appears to be a necessary condition for normal development. The reaction of developing agents including several types of chemical compounds, e.g., hydroquinone, p-aminophenol, hydroxylamine, catechol, and p-phenylenediamine, are known to exhibit this catalysis to a high degree. 

A transition step between the reaction system just considered (silver ions, p-phenylenediamine, silver sol) and actual physical development of a fixed photographic plate or film is supplied by the investigations of Arens (27, 28). He used a series of silver, gold, and silver sulfide sols which had been coated on glass plates, using gelatin as the binding material. In this way he obtained plates in which colloidal particles... 

Quantofix Peroxid Peroxidase-catalyzed oxidation of iV,iV,iV, iV -tetramethyl-p-phenylenediamine (89) best at pH 5-7. The reagents are pasted at the tip of a stick that is dipped into the test sample and after 15 s the developed color is compared with a printed scale. c... 

A proposal made about 70 years ago (13MI11400) to use p-phenylenediamines and p-aminophenols as developers which give dyes with a variety of couplers is the basis of present day practice. Since the original idea was formulated numerous developers and couplers have been synthesized. Many subtle effects within the photographic systems can be achieved as a result of the specific structure of the developers and couplers. 

Specific substituents with the p -phenylenediamine structure can influence the performance of the developing agent in several important ways. Thus, fine control of the solubility of the agent in the alkaline medium, rate of development of silver, rate of dye formation and the hue of the ultimate image dye can be achieved. 

The julolidine (43) is an active developer and gives dyes which are deeper than those from simpler p-phenylenediamines (55USP2707681). The pyrimidine (44) is a developer of low activity (56JCS3232). 

In color photography diethyl-p-phenylenediamine is an important developer because its oxidation product readily couples with a large number of phenol and reactive methylene compounds to form indoplieiiol and indoaniline dyes, which are the basis of most of the current color processes. 

If photographic materials are processed by developing solutions containing heavy metal ions, in particular iron(III) or copper ions, stains often occur. The addition of an inositolpolyphosphoric add to a color-developing solution complexes iron(III) ion, thereby preventing stain.86 In addition, aerial fog caused by heavy-metal ion catalyzed oxidation of the p-phenylenediamine color devel-... 

In another interesting amplification system, an image in silver or other noble metal nuclei is used for catalysis, and a cobalt(III) complex is used as an oxidant in place of a peroxy compound. The amplification permits less silver to be used. An imagewise distribution of silver nuclei is associated with a non-diffusible dye-forming coupler, and the image is amplified by (1) imbibing the system with a solution containing a color developer such as a p-phenylenediamine and (2)... 

In all of the examples considered, Ei/2 of the acceptor was much more negative than that of the donor. However, in liquid phase one-electron transfer from a donor to an acceptor can proceed even with an unfavorable difference in the potentials if the system contains a third component, the so-called mediator. The mediator is a substance capable of accepting an electron from a donor and sending it instantly to an acceptor. Julliard and Chanon (1983), Chanon, Rajzmann, and Chanon (1990), and Saveant (1980, 1993) developed redox catalysis largely for use in electrochemistry. As an example, the reaction of ter-achloromethane with /V,/V,/V ,Af-tetramethyl-p-phenylenediamine (TMPDA) can be discussed. The presence of p-benzoquinone (Q) in the system provokes electron transfer (Sosonkin et al. 1983). Because benzoquinone itself and tetrametyl-p-phenylenediamine interact faintly, the effect is evidently a result of redox catalysis. The following schemes reflect this kind of catalysis ... 

Dissolve 5 mg in 5 ml of 0.1 M hydrochloric acid and add 3 mg of p-phenylenediamine dihydrochloride shake to dissolve and add 0.1 g zinc powder. After mixing, allow to stand for 2 min and add 10 ml of ferric ammonium sulfate solution. A blue or violet-blue color develops [7],... 

Uses As a fine-grain silver solvent a substitute for p-phenylenediamine or very weak developing agent. Usually used in combination with metol. 

Notes p-Phenylenediamine is the classic superfine-grain developer. Besides the cautions that follow, it requires strong overexposure of the film and a very long developing time, often twenty minutes or more, and even then the contrast of the resulting negatives is rather low. 

As a result, there have been efforts to replace p-phenylenediamine with other agents. One of the more successful is the Windisch Superfine-Grain Developer that uses o-phenylenediamine. This agent also has weak developing properties, but it works as a good solvent for silver halide. 

This fine grain developer has unusually high speed and extremely fine grain due to the combination of p-phenylenediamine and pyrocatechin. 

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