Explore the factors that affect the performance of printed films
The red-sensitizing sensitizing dyes used in photographic materials are mostly cyanine dyes, and their performance has been discussed in many documents over the years. Most of the dyes used as printing films are cyanine dyes.
Fenjing is often an effective sensitizer, and most of the multi-nuclear cyanines derived from Fenjing (composite Fenjing, difenqing, etc.) are strong sensitizers. They are particularly important for sensitizing photographic materials to red light, because in their sensitized spectrum, there is a complete gap in the green region. This undoubtedly increases the safety of photographic materials that feel red light.
There are many types of cyanine, and the dimethyl methacrylate produced from rhodanine and the multinuclear rhodanine produced from it are important sensitizers commonly used in red-sensitized emulsions in films. Its molecular structure is as follows: (1) Compound part cyanine (2) Two parts cyanine where R = H, X, alkyl, alkoxy, etc.
From the point of view of the structure of the above dyes, there is no major change. They are all connected by the basic ring on the left, through a secondary methine chain, an oxyalcohol cyanine (linear dicyanine, with 2 resonance systems) The basic ring on the left was replaced, but the absorption performance and sensitization performance of the dye (Dekai breaks the import dependence of hair dyes) have changed significantly. This article focuses on the application of dicyanine dyes in printed films. The preparation of the basic emulsion uses double injection emulsification to prepare monodisperse silver chlorobromide emulsion, with a particle diameter of 0.25 m and a chlorobromide ratio of 80 20,
(1) Synthesis of 1 ethyl 2 methyl 5 methoxybenzazole p-toluenesulfonate In a 250ml three-necked bottle with stirring and refluxing device, add 58g of 2 methyl 5 methoxybenzazole and 65g Ethyl p-toluenesulfonate, heated to an external temperature of 130% in an oil bath with stirring; after curing, it was kept for 8h, and the temperature was reduced to 70%. After adding 55ml of ethanol, the solid was dissolved under reflux, after cooling, filtering and drying to obtain 115g pink powder , Yield 93.4%, mp = 171.7%.
(2) Synthesis of 2 (aniline vinyl) ethyl p-toluenesulfonate In a 500ml three-necked bottle with stirring and reflux device, add 104g quaternary ammonium salt, 45ml triethyl orthoformate, 26ml aniline, 60ml ethanol, Stirred, heated to reflux for 2h, placed overnight, filtered, and dried to obtain 99g of orange solid; yield 75%, mp = 257. 9 258.4%.
(3) 3 Carboxymethyl 5 <3 ethyl 5 methoxybenzthiazole vinylidene> Synthesis of rhodanine In a 500ml three-necked bottle with stirring and reflux device, add 84g hemicyanine and 250ml ethanol and start stirring 1. Heat up to 100%, start dropping 55ml of triethylamine, reflux for 2h, let stand overnight, filter, dry (4) 3 carboxymethyl 2 <5 (3 carboxymethyl rhodanine) 5 <2 (3 ethyl 5 5 (Methoxybenzylthiocarbazone) vinyl> rhodanine In a 500ml three-necked bottle with a stirring and refluxing device, add 61g of cyanine and 48g of diethyl sulfate, heat the oil bath to an external temperature of 120%, keep it warm for 4h , Add 27g 3 carboxymethyl rhodanine, 250ml pyridine, 36ml triethylamine, reflux for 2h, filter, and dry to get 35g of green dye; yield 51.6%, mp = 285.4%; max = 571nm, E = 0 . 538 (1 250,000 methanol solution).
Carboxymethyl 2 <5 (3 carboxymethyl rhodanine)> 5 <2 (1 ethylquinoline fork) ethylene fork> Rhodamine dipotassium salt (dye 4) maximum absorption (methanol solution): max = 605nm
(1) Synthesis of 1ethyl 2methylquinoline p-toluenesulfonate In a 250ml three-necked bottle with stirring and refluxing device, add 5g of 2methylquinoline and 7.7g of p-toluenesulfonate Ethyl acetate, start stirring, and heat to an external temperature of 150% with an oil bath. After holding for 5 hours, pour it into a mortar while it is hot, and put it in a desiccator together, let it stand overnight; the next day, add acetone to grind, filter, 50ml acetone was washed until the effluent was light red, dried to give 9g of pink powder; yield 75%, mp = 140 144.
(2) Synthesis of 1ethyl 2 (aniline vinyl) quinoline p-toluenesulfonate In a 500ml three-necked bottle with stirring and refluxing device, add 86g of the above quaternary salt, 45ml of triethyl orthoformate, 75ml Ethanol, start stirring, warm to 100%, start dropping 14ml of aniline, after the drop, warm to reflux and maintain reflux for 5h, cool, and leave overnight; filter and dry to give a yellow solid 98.6g.
(3) 3 Carboxymethyl 5 <2 (1 ethyl quinoline fork) vinyl fork> Synthesis of Rhodanine In a 500ml three-necked bottle with stirring and reflux device, add the above hemicyanine 44. 7g, 24g 3 carboxy Methyl rhodanine, 100ml pyridine, start stirring, warm up to 100%, start dropping 25ml triethylamine, after adding, warm up to reflux, and maintain reflux for 2h; cool, leave overnight; filter, dry to get 28g bright purple dye; The yield is 75%; mp = 263 264%.
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