Resin Yellow

Gelb-guss, m. yellow brass, -harz, n. yellow resin yellow rosin, -heit, /. yellowness, -holz, n. fustic, specif, old fustic 3 dlowwood. 

Another process for silicon carbide fibers, developed by Verbeek and Winter of Bayer AG [45], also is based on polymeric precursors which contain [SiCH2] units, although linear polysilmethylenes are not involved. The pyrolysis of tetramethylsilane at 700°C, with provision for recycling of unconverted (CHg Si and lower boiling products, gave a polycarbosilane resin, yellow to red-brown in color, which was soluble in aromatic and in chlorinated hydrocarbons. Such resins could be melt-spun but required a cure-step to render them infusible before they were pyrolyzed to ceramic... 

Amber Organic Origin Fossil resin Yellow//brown/red... 

Phenol-formaldehyde resin Yellow, smoky Phenol, formaldehyde Very difficult to ignite, vapor reaction neutral... 

Exposed to prolonged radiation, resin yellows faster than other t3 es of polyamide. 

White glues, based on polyvinyl acetate, are of course quite common, but there is a trend toward the aliphatic resin yellow wood glues for this finish work. Not all yellow-colored glues are based on aliphatic resin. One advantage of the aliphatic resins is their built-in heat resistance, which allows them to be sanded where the white glues would gum up the sand paper. Also, they diy quite rapidly, faster than most white glues. The true aliphatic resin can be detected by the fact that it has a tacky characteristic normally not found in white glues. 

CH2=CHC = CCH = CH2. a colourless liquid which turns yellow on exposure to the air it has a distinct garlic-like odour b.p. 83-5°C. Manufactured by the controlled, low-temperature polymerization of acetylene in the presence of an aqueous solution of copper(I) and ammonium chlorides. It is very dangerous to handle, as it absorbs oxygen from the air to give an explosive peroxide. When heated in an inert atmosphere, it polymerizes to form first a drying oil and finally a hard, brittle insoluble resin. Reacts with chlorine to give a mixture of chlorinated products used as drying oils and plastics. 

On heating gives a yellow resin having a characteristic colour. 

Action of sodium hydroxide, (a) Warm 1 ml. of acetaldehyde with a few ml. of cone, (c.g., 30%) NaOH solution. A yellow resin, having a characteristic odour of bad apples, is formed. Paraldehyde slowly gives a yellow resin. 

Gives some of the tests for acetaldehyde, but more feebly e.g., it restores the colour to SchifF s reagent, gives a yellow resin with NaOH, and responds to the nitroprusside test. With ammoniacal AgN03, it gives a silver minor only after 2 -3 minutes warming. It does not give the iodoform reaction. 

NaOH Cannizzaro s reaction < yellow resin > chloroform on heating Cannizzaro s reaction yellow coloration... 

Now warm 2-3 drops of acetaldehyde with 3-4 ml. of 10-20 per cent, sodium hydroxide solution, i.e., with excess of concentrated alkali solution. Observe the formation of a yellow aldehyde resin and the attendant peculiar odour. 

To isolate the p-hydroxybenzaldehyde, filter the residue from the steam distillation while hot through a fluted filter paper in order to remove resinous matter, and extract the cold filtrate with ether. Distil off the ether, and recrystallise the yellow solid from hot water to which some aqueous sulphurous acid is added. The yield of p-hydroxybenzaldehyde (colourless crystals), m.p. 116°, is 2-3 g. 

The amino add analysis of all peptide chains on the resins indicated a ratio of Pro Val 6.6 6.0 (calcd. 6 6). The peptides were then cleaved from the resin with 30% HBr in acetic acid and chromatogra phed on sephadex LH-20 in 0.001 M HCl. 335 mg dodecapeptide was isolated. Hydrolysis followed by quantitative amino acid analysis gave a ratio of Pro Val - 6.0 5.6 (calcd. 6 6). Cycll2ation in DMF with Woodward s reagent K (see scheme below) yielded after purification 138 mg of needles of the desired cyc-lododecapeptide with one equiv of acetic add. The compound yielded a yellow adduct with potassium picrate, and here an analytically more acceptable ratio Pro Val of 1.03 1.00 (calcd. 1 1) was found. The mass spectrum contained a molecular ion peak. No other spectral measurements (lack of ORD, NMR) have been reported. For a thirty-six step synthesis in which each step may cause side-reaaions the characterization of the final product should, of course, be more elaborate. 

Benzil. Ben il [134-81-6] (diphenylethanedione) is a yellow soHd that crystallines from alcohol in hexagonal prisms. Ben nil can be prepared by the oxidation of bennoin [579-44-2] (2-hydroxy-2-phenylacetophenone) (298,299), which is itself prepared by the self-condensation of bennaldehyde (300). Ben nil is commercially produced in Japan and is used as a uv resin curing sensitizer (301). It has also been suggested as a chigger repeUant (302). 

Brown coals yield, on solvent extraction, 10—15% of a material that contains 60—90% light yellow or brown waxy substances. The remainder is a mixture of deep brown resinous and asphaltic substances. The yield may be increased by increasing the pressure during extraction, but this also adds dark colored dispersion products, and the resultant brown coal caimot be briquetted. 

Post-curing and chemical modification improves chemical and solvent resistance (20). Paraformaldehyde and acetylene diurea are added to a hot borax solution. Toluenesulfonamide (p and o), a few drops of phosphorous acid. Brilliant Yellow 6G [2429-76-7] Rhodamine E3B, and Rhodamine 6GDN [989-38-8] are added. After heating, the mass is cured in an oven at 150°C. The resulting cured resin is thermoset but can be ground to fine particle sizes. 

Methyl methacrylate is often used in combination with styrene to improve light transmission and uv stabiUty in fiame-retardant glazing appHcations. Phosphate ester (triethyl phosphate) additives are also included to supplement fiame-retardant efficiency benzophenone uv stabilizers are required to prevent yellowing of these uv-sensitive resins. 

Reactions. Saligenin [90-01-7] undergoes the typical reactions of phenols and benzyl alcohol. When heated above 100°C, it transforms into a pale yellow resinous material. Amorphous condensation products are obtained when saligenin reacts with acetic anhydride, phosphoms pentachloride, or mineral acids. Upon boiling with dilute acids, saligenin is converted into a resinous body, saliretin, a condensed form of saligenin. Condensation reactions of saligenin with itself in the absence of any catalysts and in the presence of bases have also been studied. 

Titanate Pigments. When a nickel salt and antimony oxide are calcined with mtile titanium dioxide at just below 1000°C, some of the added metals diffuse into the titanium dioxide crystal lattice and a yellow color results. In a similar manner, a buff may be produced with chromium and antimony a green, with cobalt and nickel and a blue, with cobalt and aluminum. These pigments are relatively weak but have extreme heat resistance and outdoor weatherabihty, eg, the yellow is used where a light cadmium could not be considered. They are compatible with most resins. 

In general, the azo colors are useful for coloring polystyrene, phenoHcs, and rigid poly(vinyl chloride). Many are compatible with poly(methyl methacrylate), but in this case the weatherabiUty of the resin far exceeds the life of the dyes. Among the more widely used azo dyes (qv) are Solvent Yellows 14 and 72 Orange 7 and Reds 1, 24, and 26. 

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