Solvent extracts, drying

The anionic is precipitated as its p-toluidine salt, solvent-extracted, dried and weighed. It is then titrated in alcoholic solution with sodium hydroxide, which displaces the weak base. 

Separate the oil, and extract the aqueous layer with three 100 ml. portiom of benzene. Combine the oil and benzene extracts, dry with anhydrous magnesium sulphate, remove the solvent, and distil the residue under diminished pressure. Collect the a-tetralone at 105-107°/2 mm, (or at 135-137715 mm,). The yield is 23 g. 

Several standard methods for the quantitative analysis of food samples are based on measuring the sample s mass following a selective solvent extraction. For example, the crude fat content in chocolate can be determined by extracting with ether for 16 h in a Soxhlet extractor. After the extraction is complete, the ether is allowed to evaporate, and the residue is weighed after drying at 100 °C. This analysis has also been accomplished indirectly by weighing a sample before and after extracting with supercritical GO2. 

Exceptions to the simple definition of an essential oil are, for example, gadic oil, onion oil, mustard oil, or sweet birch oils, each of which requires enzymatic release of the volatile components before steam distillation. In addition, the physical process of expression, appHed mostly to citms fmits such as orange, lemon, and lime, yields oils that contain from 2—15% nonvolatile material. Some flowers or resinoids obtained by solvent extraction often contain only a small portion of volatile oil, but nevertheless are called essential oils. Several oils are dry-distiUed and also contain a limited amount of volatiles nonetheless they also are labeled essential oils, eg, labdanum oil and balsam oil Pern. The yield of essential oils from plants varies widely. Eor example, nutmegs yield 10—12 wt % of oil, whereas onions yield less than 0.1% after enzymatic development. 

Turpentine Oil. The world s largest-volume essential oil, turpentine [8006-64-2] is produced ia many parts of the world. Various species of piaes and balsamiferous woods are used, and several different methods are appHed to obtain the oils. Types of turpentines include dry-distiUed wood turpentine from dry distillation of the chopped woods and roots of pines steam-distilled wood turpentine which is steam-distilled from pine wood or from solvent extracts of the wood and sulfate turpentine, which is a by-product of the production of sulfate ceUulose. From a perfumery standpoint, steam-distilled wood turpentine is the only important turpentine oil. It is rectified to yield pine oil, yellow or white as well as wood spirits of turpentine. Steam-distilled turpentine oil is a water-white mobile Hquid with a refreshing warm-balsamic odor. American turpentine oil contains 25—35% P-pinene (22) and about 50% a-pinene (44). European and East Indian turpentines are rich in a-pinene (44) withHtfle P-pinene (22), and thus are exceUent raw materials... 

Soybeans. Vktuady ad soybeans processed in the United States are solvent-extracted with hexane to recover the od. This traditional process is outlined in Figure 4. Beans arriving at the plant are cleaned and dried, if necessary, before storage. When the beans move from storage to processing, they are cleaned further and may be dried and adowed to equdibrate at 10—11% moisture to facditate loosening of the seed coat or hud. They are then cracked. 

Chemical Precipitation. The product of the extraction processes, whether derived from acid or carbonate leach, is a purified uranium solution that may or may not have been upgraded by ion exchange or solvent extraction. The uranium ia such a solution is concentrated by precipitation and must be dried before shipment. Solutions resulting from carbonate leaching are usually precipitated directly from clarified leach Hquors with caustic soda without a concentration step, as shown ia equation 9. 

For solvent extraction of pentavalent vanadium as a decavanadate anion, the leach solution is acidified to ca pH 3 by addition of sulfuric acid. Vanadium is extracted in about four countercurrent mixer—settler stages by a 3—5 wt % solution of a tertiary alkyl amine in kerosene. The organic solvent is stripped by a soda-ash or ammonium hydroxide solution, and addition of ammoniacal salts to the rich vanadium strip Hquor yields ammonium metavanadate. A small part of the metavanadate is marketed in that form and some is decomposed at a carefully controlled low temperature to make air-dried or fine granular pentoxide, but most is converted to fused pentoxide by thermal decomposition at ca 450°C, melting at 900°C, then chilling and flaking. 

For vanadium solvent extraction, Hon powder can be added to reduce pentavalent vanadium to quadrivalent and trivalent Hon to divalent at a redox potential of —150 mV. The pH is adjusted to 2 by addition of NH, and an oxyvanadium cation is extracted in four countercurrent stages of mixer—settlers by a diesel oil solution of EHPA. Vanadium is stripped from the organic solvent with a 15 wt % sulfuric acid solution in four countercurrent stages. Addition of NH, steam, and sodium chlorate to the strip Hquor results in the precipitation of vanadium oxides, which are filtered, dried, fused, and flaked (22). Vanadium can also be extracted from oxidized uranium raffinate by solvent extraction with a tertiary amine, and ammonium metavanadate is produced from the soda-ash strip Hquor. Fused and flaked pentoxide is made from the ammonium metavanadate (23). 

The standard chemical and biological methods of analysis are those accepted by the JnitedStates Pharmacopeia XXIII as well as the ones accepted by the AO AC in 1995 (81—84). The USP method involves saponification of the sample (dry concentrate, premix, powder, capsule, tablet, or aqueous suspension) with aqueous alcohoHc KOH solvent extraction solvent removal chromatographic separation of vitamin D from extraneous ingredients and colormetric deterrnination with antimony trichloride and comparison with a solution of USP cholecalciferol reference standard. 

To a stirred and refluxing solution of 40 parts of benzene and 35 parts of dimethylformamide (both solvents previously dried azeotropically) are added successively 1.6 parts of sodium hydride and 7.7 parts of Ct-(2,4-dichlorophenyl)imidazole-1-ethanol, (coolingon ice is necessary). After the addition is complete, stirring and refluxing is continued for 30 minutes. Then there are added 7.8 parts of 2,6-dichlorobenzyl chloride and the whole is stirred at reflux for another 3 hours. The reaction mixture is poured onto water and the product 1-[2,4-dichloro-/3 (2,6-dichlorobenzyloxy)phenethyl] imidazole, is extracted with benzene. The extract is washed twice with water, dried, filtered and evaporated in vacuo. The bese residue is dissolved in a mixture of acetone and diisopropyl ether and to this solution is added an excess of concentrated nitric acid solution. The precipitated nitrate salt is filtered off and recrystallized from a mixture of methanol and diisopropyl ether, yielding 1-[2,4-dichloro- (2,6-dichlorobenzyl-oxv)phenethyl] imidazole nitrate melting point 179°C. 

A solution containing 741 g (5.0 mols) of 1-phenyl-2-propylidenylhydrazine, 300 g (5.0 mols) of glacial acetic acid and 900 cc of absolute ethanol was subjected to hydrogenation at 1,875 psi of hydrogen in the presence of 10 gof platinum oxide catalyst and at a temperature of 30°C to 50°C (variation due to exothermic reaction). The catalyst was removed by filtration and the solvent and acetic acid were distilled. The residue was taken up In water and made strongly alkaline by the addition of solid potassium hydroxide. The alkaline mixture was extracted with ether and the ether extracts dried with potassium carbonate. The product was collected by fractional distillation, BP B5°C (0.30 mm) yield 512 g (68%). 

Preparation of 3-Amino-5-Methylisox3Zo/e 1.7 grams of ethyl 5-methylisoxa2ole-3-car-bamate was heated on a boiling water-bath with 5 cc of a 10% aqueous sodium hydroxide solution for 8 hours, then the reaction mixture was extracted several times with ether or benzene and the extract was cooled followed by the removal of the solvent and drying. The residue was solidified after a while and gave prismatic crystals, melting point 61° to 62°C, of 3-amino-5-methylisoxazole by recrystallization from benzene. 

A solution of 2 -(bromomethyl)biphenyl-2-carbaldehyde (45 1 g 3.6 mmol) and 25 % aq NH3 (20 mL) in EtOH (100 mL) was heated under reflux for 5 h. The mixture was cooled and stirred for 15 min with 10% aq NaOH (20 mL). The basic solution was extracted with CH2C12, the extract dried, and the solvent evaporated to give the product as an oil which was purified by flash chromatography (silica gel, Et20/ hexane) yield 0.667 g (95%) mp 84-85 C... 

The lyophilization procedure, as described, is suitable for materials such as vegetables, that do not usually contain much nonaqueous volatile matter. For other materials, rich in these volatiles, a modification of the procedure would be required. The volatiles could in some cases be extracted with a solvent and dried separately (28), or the substances evolved in the drying could be collected and analyzed for the amount of nonaqueous material. 

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