Adip solutions

The transition voltage depends on the formation current density. At formation current densities above 2.5 mA/cm, the transition voltage was greater than 60 V. Chang et al. [11] reported that the transition voltage was 150 V when the films were formed at 25 mA/cm in 0.83 M ammonium adipate solution. 

Standards in use for quantitation are essentially employed in three ways. With the internal standard technique, known quantities of a carefully selected (usually high purity) substance, the internal standard, are added to both samples and standards. The internal standard (preferably a non-commercial product) should have similar chemical and physical properties to the analyte, in particular, volatility and functional groups, in order to react in the same way to changes in the chemical environment (e.g. dinonyl adipate may serve as an internal standard for the determination of di(2-ethylhexyl) adipate). Solutions of pure additives used as standards may be unsatisfactory due to the difference in the evaporation profile between pure additives and those blended in the polymer samples. For example, a pure Permanax WSP sample evaporates in the ion source from about 30 to 150°C, whereas Permanax WSP blended in PE evaporates from about 120 C (m.p. of PE) to 350°C [17]. If one opts for polymer-based calibration standards the homogeneity of the samples is of crucial importance. Using internal standards in quantitative analysis is advantageous, for instance, in cases where the sample thickness cannot be determined exactly, or in gaseous samples with unknown total pressure. 

Place 100 g. of adipic acid in a 750 ml. round-bottomed flask and add successively 100 g. (127 ml.) of absolute ethyl alcohol, 250 ml. of sodium-dried benzene and 40 g. (22 ml.) of concentrated sulphuric acid (the last-named cautiously and with gentle swirling of the contents of the flask). Attach a reflux condenser and reflux the mixture gently for 5-6 hours. Pour the reaction mixture into excess of water (2-3 volumes), separate the benzene layer (1), wash it with saturated sodium bicarbonate solution until eflfervescence ceases, then with water, and dry with anhydrous magnesium or calcium sulphate. Remove most of the benzene by distillation under normal pressure until the temperature rises to 100° using the apparatus of Fig. II, 13, 4 but substituting a 250 ml. Claisen flask for the distilling flask then distil under reduced pressure and collect the ethyl adipate at 134-135°/17 mm. The yield is 130 g. 

Dissolve 7 g. of pure oleic acid in 30 ml. of dry ethyl chloride (chloroform may be used but is less satisfactory), and ozonise at about —30°. Remove the solvent under reduced pressure, dissolve the residue in 50 ml. of dry methyl alcohol and hydrogenate as for adipic dialdehyde in the presence of 0 5 g. of palladium - calcium carbonate. Warm the resulting solution for 30 minutes with a slight excess of semicarbazide acetate and pour into water. Collect the precipitated semicarbazones and dry the... 

Sebacic acid. Dissolve 40 g. of methyl hydrogen adipate in 100 ml. of absolute methanol to which 01 g. of sodium has been added. Pass a current of about 2 0 amps, until the pH of the solution is about 8 (ca. 5 hours) test with B.D.H. narrow-range indicator paper. Transfer the contents of the electrolysis cell to a 500 ml. round-bottomed flask, render neutral with a little acetic acid, and distil off the methanol on a water... 

Myristic acid from hexanoic acid and methyl hydrogen sebacate). Dissolve 23 -2 g. of redistilled hexanoic acid (re caproic acid), b.p. 204-6-205-5°/760 mm., and 21-6 g. of methyl hydrogen sebacate in 200 ml. of absolute methanol to which 0 13 g. of sodium has been added. Electrolyse at 2 0 amps., whilst maintaining the temperature between 30° and 40°, until the pH is about 8 0 (ca. 6 hours). Neutralise the contents of the electrolysis cell with a little acetic acid and distil off the methyl alcohol on a water bath. Dissolve the residue in 200 ml. of ether, wash with three 50 ml. portions of saturated sodium bicarbonate solution, once with water, dry with anhydrous magnesium sulphate, and distil with the aid of a fractionating column (see under Methyl hydrogen adipate). Collect the re-decane at 60°/10 mm. (3 0 g.), the methyl myristate at 158-160°/ 10 mm. (12 5g.) and dimethyl hexadecane-1 16-dicarboxylate at 215-230°/ 7 mm. (1 -5 g.)... 

Add 40 ml. of ethyl alcohol to 21 -5 g. of 70 per cent, ethylenediamine solution (0 -25 mol) dissolve 36 -5 g. of adipic acid (0 -25 mol) in 50 ml. of a 6 1 mixture of ethyl alcohol and water. Mix the two solutions, stir and cool. Filter off the resulting salt and recrystalliae it from 60 ml. of a 6 1 ethyl alcohol - water mixture, and dry the salt in the air. Heat the salt in an atmosphere of oxygen-free nitrogen or of carbon dioxide in an oil bath until it melts (ca. 160°) the product will sohdify after a short time. Reduce the pressure to 15 mm. of mercury or less and raise the temperature of the oil bath until the product remelts (about 290°) and continue the heating for 4r-5 hours. Upon coohng, a nylon type polymer is obtained. 

Add 10 ml. of concentrated sulphuric acid cautiously to 45 ml. of water contained in a 200 ml. round-bottomed flask, introduce 3 g. of Nylon 66 polymer into the hot solution, and heat under reflux for 6 hours. Allow to stand for 1 hour and cool in ice for a further hour. Filter off the solid and keep the filtrate. Recrystalhse the sohd (adipic acid) from water m.p. 152°. 

Amidation. Heating of the diammonium salt or reaction of the dimethyl ester with concentrated ammonium hydroxide gives adipamide [628-94-4] mp 228°C, which is relatively insoluble in cold water. Substituted amides are readily formed when amines are used. The most industrially significant reaction of adipic acid is its reaction with diamines, specifically 1,6-hexanediamine. A water-soluble polymeric salt is formed initially upon mixing solutions of the two materials then hea ting with removal of water produces the polyamide, nylon-6,6. This reaction has been studied extensively, and the hterature contains hundreds of references to it and to polyamide product properties (31). 

Analytical Procedures. Standard methods for analysis of food-grade adipic acid are described ia the Food Chemicals Codex (see Refs, ia Table 8). Classical methods are used for assay (titration), trace metals (As, heavy metals as Pb), and total ash. Water is determined by Kad-Fisher titration of a methanol solution of the acid. Determination of color ia methanol solution (APHA, Hazen equivalent, max. 10), as well as iron and other metals, are also described elsewhere (175). Other analyses frequendy are required for resia-grade acid. For example, hydrolyzable nitrogen (NH, amides, nitriles, etc) is determined by distillation of ammonia from an alkaline solution. Reducible nitrogen (nitrates and nitroorganics) may then be determined by adding DeVarda s alloy and continuing the distillation. Hydrocarbon oil contaminants may be determined by ir analysis of halocarbon extracts of alkaline solutions of the acid. 

Environmental Aspects. Airborne particulate matter (187) and aerosol (188) samples from around the world have been found to contain a variety of organic monocarboxyhc and dicarboxyhc acids, including adipic acid. Traces of the acid found ia southern California air were related both to automobile exhaust emission (189) and, iadirecfly, to cyclohexene as a secondary aerosol precursor (via ozonolysis) (190). Dibasic acids (eg, succinic acid) have been found even ia such unlikely sources as the Murchison meteorite (191). PubHc health standards for adipic acid contamination of reservoir waters were evaluated with respect to toxicity, odor, taste, transparency, foam, and other criteria (192). BiodegradabiUty of adipic acid solutions was also evaluated with respect to BOD/theoretical oxygen demand ratio, rate, lag time, and other factors (193). 

The molecular weight and its distribution have been determined by laser light scattering, employing a new apparatus for ETFE dissolution and solution clarification at high temperature diisobutyl adipate is the solvent at 240°C. The molecular weight of molten ETEE is determined by high temperature rheometry (21). 

The second difficulty, degradation, required the development of a two-step polyamidation process following salt formation (157). During salt formation, tetramethylenediammonium adipate salt is formed in water solution at approximately 50% concentration or at a higher concentration in a suspension. As in nylon-6,6 manufacture, this salt solution, when diluted, permits easy adjustment of the stoichiometry of the reactants by means of pH measurement. 

Poly(methyl methacrylate) and poly(vinyl acetate) precipitate from the resin solution as it cures. This mechanism offsets the contraction in volume as the polyester resin cross-links, resulting in a nonshrinking thermoset. Other polymer additives such as poly(butylene adipate) provide similar shrinkage... 

Succinic anhydride [108-30-5] (3,4-dihydro-2,5-furandione butanedioic anhydride tetrahydro-2,5-dioxofuran 2,5-diketotetrahydrofuran succinyl oxide), C H O, was first obtained by dehydration of succinic acid. In the 1990s anhydride is produced by hydrogenation of maleic anhydride and the acid by hydration of the anhydride, by hydrogenation of aqueous solutions of maleic acid, or as a by-product in the manufacture of adipic acid (qv) (see Maleic ANHYDRIDE, MALEIC ACID, AND FUMARIC ACID). 

Succinic acid reacts with urea in aqeous solution to give a 2 1 compound having mp 141°C (116,117), which has low solubiUty in water. A method for the recovery of succinic acid from the wastes from adipic acid manufacture is based on this reaction (118,119). The monoamide succinamic acid [638-32-4] NH2COCH2CH2COOH, is obtained from ammonia and the anhydride or by partial hydrolysis of succinknide. The diamide succinamide [110-14-3], (CH2C0NH2)2, nip 268—270°C, is obtained from succinyl chloride and ammonia or by partial hydrolysis of succinonitrile. Heating succinknide with a primary amine gives A/-alkylsucckiknides (eq. 9). 

Dicarboxyhc acids, eg, succinic or adipic, do not dissolve titanic acid. A phthalate has been prepared by adding acidic titanium sulfate solution to sodium phthalate solution. 

Of the removal processes that have attained commercial status, the current favorite employs a shiny of lime or limestone. The activity of the reagent is promoted by the addition of small amounts of carboxylic acids such as adipic acid. The gas and the shiny are contacted in a spray tower. The calcium salt is discarded. A process that employs aqueous sodium citrate, however, is suited for the recoveiy of elemental sulfur. The citrate solution is regenerated and recycled. (Kohl and Riesenfeld, Gas Purification, Gulf, 1985, p. 356.)... 

To a solution of 33 g. (O.S mole) of potassium hydroxide (Note 1) in 1.5 1. of distilled water in a 5-1. flask or other appropriate container fitted with a mechanical stirrer is added 80 g. (0.5 mole) of methyl hydrogen adipate (Note 2). With continuous stirring a solution of 85 g. (0.5 mole) of silver nitrate in 1 1. of distilled water is added rapidly (about IS minutes). The precipitated methyl silver adipate is collected on a Buchner funnel, washed with methanol, and dried in an oven at 50-60°. For the next step the dried silver salt is finely powdered and sieved through a 40-mesh screen. The combined yield from two such runs is, 213 g. (80%). 

A. Diethyl a,h-dibromoadipate. In a 3-1. three-necked flask (Note 1) fitted with a reflux condenser, a dropping funnel, and a mechanical stirrer are placed 1 kg. (6.85 moles) of adipic acid and 2 kg. (1220 ml., 16.8 moles) of thionyl chloride (Notes 2 and 3). The mixture is stirred and heated gently on the steam bath until solution is effected, and the evolution of hydrogen chloride (Note 4) ceases after about 3 hours. The excess thionyl chloride... 

According to the literature, the product obtained in this manner may contain ethyl adipate. To remove this, the product is cooled to 0° and run slowly into 600 cc. of 10 per cent potassium hydroxide solution maintained at 0° with ice-salt. Water is added until the salt which separates has dissolved, and the cold alkaline solution is extracted twice with 200-cc. portions of ether. The alkaline solution, kept at 0°, is run slowly into 900 cc. of 10 per cent acetic acid solution with stirring, the temperature remaining below 1° (ice-salt). The oil which separates is taken up in 400 cc. of ether, and the aqueous solution is extracted with four 250-cc. portions of ether. The ether extract is washed twice with cold 7 per cent sodium carbonate solution and dried over sodium sulfate. After removal of the ether the residue is distilled, b.p. 7g-8i°/3 mm. The recovery is only 80-85 per cent, and in a well-conducted preparation the ethyl adipate eliminated amounts to less than one per cent of the total product. Unless the preparation has proceeded poorly the tedious purification ordinarily is best omitted. 

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