Orange yields

On evaporation oti a watcr-batb, sweel orange oil yields from J-.O lo 4 per cent, ot fixed ru.sidue, which has an acid value of H to 30 and an ester value of li-o lo 170. Spanish orange oil, however, which is expressed From a dark-skinned orange, yields from 7 to 0 pur cent. o[ fixed... 

After standing for 1 week at 40-45 °C, the mixture is cooled to ice temperature, and the red crystals are collected on a coarse, sintered glass frit. Air drying causes the crystals to lose much of their crystallinity the material isolated is red-orange. Yield 15.0g (75%). 

When the distillation is complete, filter olT the crude orange solid (9 g.) at the pump, wash it wdth water and drain well. Recrystallise from methanol or from methylated spirits. The p-bromobiphenyl is obtained as colourless lustrous plates, m.p. 89-91 " yield, 7 g. 

To obtain the free acid, dissolve the potassium salt in 50 ml. of cold water, filter the solution if a small undissolved residue remains, and then boil the clear solution gently whilst dilute sulphuric acid is added until the separation of the acid is complete. Cool the solution and filter off the pale orange-coloured crystals of the benzilic acid wash the crystals on the filter with some hot distilled water, drain well, and then dry in a desiccator. Yield of crude acid, 4 g. Recrystallise from benzene (about 50 ml.) to which a small quantity of animal charcoal has been added, filtering the boiling solution through a preheated funnel fitted w ith a fluted filter-paper, as the benzilic acid readily crystallises as the solution cools alternatively, recrystallise from much hot water. The benzilic acid is obtained as colourless crystals, m.p. 150°. 

Dissolve 10 g. of chloro- 2,4-dinitrobenzenet in 50 ml. of dioxan in a 250 ml. conical flask. Dilute 8 ml. of hydrazine hydrate with an equal volume of water and add this slowly with shaking to the dioxan solution, keeping the temperature between zo " and 25°. Heat under reflux for 10 minutes to complete the reaction and then add 5 ml. of ethanol and heat again for 5 minutes. Cool and filter oflF the orange 2,4-dinitrophenylhydra-zine. Recrystallise the dry product from ethyl acetate m.p. 200° (decomp.). Yield, 7 g. 

Whilst the solution is still hot, add dilute hydrochloric acid until the stirred solution is just acid to litmus, and then distil off as much ethanol as possible, using the water-bath. Now add more dilute hydrochloric acid to the residual hot solution until it is just acid to methyl-orange. The 5,5-dimethyl-cyclohexan-1,3-dione separates as an oil which solidifies on cooling. Filter the product at the pump, wash it with ice-cold water, and dry it in a desiccator. Yield of the pale cream-coloured crystals, 12 g. m.p. 136-145 (preliminary softening). 

Make a thin paste of 21 5 g. of finely-powdered o-tolidine (a commercial product) with 300 ml. of water in a 1-litre beaker, add 25 g. (21 ml.) of concentrated hydrochloric acid, and warm until dissolved. Cool the solution to 10° with ice, stir mechanically, and add a further 25 g. (21 ml.) of concentrated hydrochloric acid (1) partial separation of o tolidine dihydrochloride will occur. Add a solution of 15 g, of sodium nitrite in 30 ml. of water as rapidly as possible, but keep the temperature below 15° a slight excess of nitrous acid is not harmful in this preparation. Add the clear, orange tetrazonium solution to 175 ml. of 30 per cent, hypophosphorous acid (2), and allow the mixture to stand, loosely stoppered, at room temperature for 16-18 hours. Transfer to a separatory funnel, and remove the upper red oily layer. Extract the aqueous layer with 50 ml, of benzene. Dry the combined upper layer and benzene extract with anhydrous magnesium sulphate, and remove the benzene by distillation (compare Fig. II, 13, 4) from a Widmer or similar flask (Figs. II, 24, 3-5) heat in an oil bath to 150° to ensure the removal of the last traces of benzene. Distil the residue at ca. 3 mm. pressure and a temperature of 155°. Collect the 3 3 -dimethyldiphenyl as a pale yellow liquid at 114-115°/3 mm. raise the bath temperature to about 170° when the temperature of the thermometer in the flask commences to fall. The yield is 14 g. 

Method 2 (from hydrazobenzene). Prepare a solution of sodium hypobromite by adding 10 g. (3-2 ml.) of bromine dropwise to a cold solution of 6-0 g. of sodium hydroxide in 75 ml. of water immersed in an ice bath. Dissolve 9-5 g. of hydrazobenzene (Section IV,87) in 60 ml. of ether contained in a separatory funnel, and add the cold sodimn hypobromite solution in small portions. Shake for 10 minutes, preferably mechanically. Separate the ether layer, pour it into a 100 ml. distilling flask, and distil off the ether by warming gently on a water bath. Dissolve the warm liquid residue in about 30 ml. of alcohol, transfer to a small beaker, heat to boiling on a water bath, add water dropwise to the hot solution until the azobenzene just commences to separate, render the solution clear again with a few drops of alcohol, and cool in ice water. Filter the orange crystals at the pump, and wash with a little 50 per cent, alcohol. Dry in the air. The yield is 8 g. 

Compounds containing two primary amino groups attached to a benzene ring can be prepared by the reduction of dinitro compounds and of nitroanilines, usually with tin or stannous chloride and hydrochloric acid or with iron and very dilute hydrochloric acid. / ara-diamines may also be obtained by the reduction of aromatic amino-azo compounds (e.g., p-aminodimethylanihne from methyl orange, see Section IV,78). p-Phenylenediamine may also be prepared from p-nitroacetanilide reduction with iron and acid yields p-amino-acetaniUde,.which may be hydrolysed to the diamine. 

Place 20 g. of Orange II (Section IV,79) in a 600 ml. beaker and dissolve it in 250 ml. of water at 40-50°. Add, with stirring, 24-25 g. of sodium hyposulphite (Na SjO ) this discharges the colour and yields a pink or cream-coloured, finely-divided precipitate of a-amino-p-naphthol (compare Section IV,76). Heat the mixture nearly to boiling until it commences to froth considerably, then cool to 25° in ice, filter on a... 

Free cydohexene from peroxides by treating it with a saturated solution of sodium bisulphite, separate, dry and distil collect the fraction, b.p. 81-83°. Mix 8 -2 g. of cycZohexene with 55 ml. of the reagent, add a solution of 15 mg. of osmium tetroxide in anhydrous butyl alcohol and cool the mixture to 0°. Allow to stand overnight, by which time the initial orange colouration will have disappeared. Remove the solvent and unused cydohexene by distillation at atmospheric pressure and fractionate the residue under reduced pressure. Collect the fraction of b.p. 120-140°/15 mm. this solidifies almost immediately. Recrystallise from ethyl acetate The yield of pure cis-l 2 cydohexanediol, m.p. 96°, is 5 0 g. 

Eosin (Tetrabromofluorescein). Place 16 5 g. of powdered fluorescein and 80 ml. of rectified (or methylated) spirit in a 250 ml. flask. Support a small dropping funnel, containing 36 g. (12 ml.) of bromine, above the flask make sure that the stopcock of the funnel is well lubricated before charging the latter with bromine. Add the bromine diopwise during about 20 minutes. When half the bromine has been introduced, and the fluorescein has been converted into dibromofluor-escein, all the solid material disappears temporarily since the dibromo derivative is soluble in alcohol with further addition of bromine the tetrabromofluorescein (sparingly soluble in alcohol) separates out. Allow the reaction mixture to stand for 2 hours, filter ofiF the eosin at the pump, wash it with alcohol, and dry at 100°. The yield of eosin (orange-coloured powder) is 25 g. 

The extracts were kept below 0°C (note 5). The combined extracts were washed with 5i acetic acid and subsequently dried over magnesium sulfate (note 6). The extract was concentrated in a water-pump vacuum to about 60 ml by means of the rotary evaporator, care being taken that the bath temperature remained below 25°C. The remaining pale yellow solution was warmed to about 35°C (internal temperature). The temperature rose gradually but was kept at about 45°C by occasional cooling. When after about 45 min the exothermic reaction had subsided, the flask was placed in a water-bath at 55°C. After 30 min the remaining pentane was removed in a water--pump vacuum. The orange residue, n 1.5878, yield aa. 92% was almost pure allenic dithioester. 

In the extraction of citms juices it is desirable to have as gende an extraction pressure as possible. There should be minimal contact time between juice and pulp to reduce the amount of bitter substances expressed from the peel into the juice. The amount of suspended soHds in citms juice is controlled in a subsequent separation in a finisher. A screw action is used to force the juice through a perforated screen and separate the larger pulp particles from the juice. The oil level in the juice is adjusted by vaporizing under a vacuum (10). The separated pulp is washed and finished several times to produce a solution which is then either added back to the juice to increase juice yield, or concentrated to produce pulp wash soHds, also called water extract of orange soHds, which can be used as a cloudy beverage base. 

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