Distillate compounds from

Table 17. Distillable compounds from the reaction of silicon with CH,C1,...

Choice of solvent for recrystallisation. Obtain small samples (about 0 5 g.) of the following compounds from the storeroom (i) salicylic acid, (Li) acetanilide, (iii) m-dinitrobenzene, (iv) naphthalene, and (v) p-toluene-sulphonamide. Use the following solvents distilled water, methylated spirit, rectified spirit, acetone, benzene and glacial acetic acid. 

The purification of diethyl ether (see Chapter 4) is typical of liquid ethers. The most common contaminants are the alcohols or hydroxy compounds from which the ethers are prepared, their oxidation products (e.g. aldehydes), peroxides and water. Peroxides, aldehydes and alcohols can be removed by shaking with alkaline potassium permanganate solution for several hours, followed by washing with water, concentrated sulfuric acid [CARE], then water. After drying with calcium chloride, the ether is distilled. It is then dried with sodium or with lithium aluminium hydride, redistilled and given a final fractional distillation. The drying process should be repeated if necessary. 

The compound known as 18-crown-6 is one of the simplest and most useful of the macrocyclic polyethers. Its synthesis in low yield was first reported by Pedersen. Greene and Dale and Kristiansen" have reported syntheses of the title compound from triethylene glycol and triethylene glycol di-p-toluenesulfonate. Both of these procedures use strong base and anhydrous conditions and achieve purification by more or leas classical methods. The combination of distillation and formation of the acetonitrile complex affords crown of high purity without lengthy chromatography or sublimation. ... 

Liquid solvents are used to extract either desirable or undesirable compounds from a liquid mixture. Solvent extraction processes use a liquid solvent that has a high solvolytic power for certain compounds in the feed mixture. For example, ethylene glycol has a greater affinity for aromatic hydrocarbons and extracts them preferentially from a reformate mixture (a liquid paraffinic and aromatic product from catalytic reforming). The raffinate, which is mainly paraffins, is freed from traces of ethylene glycol by distillation. Other solvents that could be used for this purpose are liquid sulfur dioxide and sulfolane (tetramethylene sulfone). 

Step 3. The non-steam-volatile compounds. The alkaline solution (5j) remaining in the distilling flask from Step 2 may contain water-soluble, non-volatile acidic, basic or neutral compounds. Add dilute sulphuric acid imtil the solution is just acid to Congo red, evaporate to dj ess, and extract the residual solid with boihng absolute ethyl alcohol extraction is complete when the undissolved salt exhibits no sign of charring when heated on a metal spatula in the Bimsen flame. Evaporate the alcoholic solution to dryness and identify the residue. 

Distillation is a suitable technique for the isolation of volatile organic compounds from liquid samples or the soluble portion of solid samples [24,27-30]. The physical basis of separation depends on the distribution of constituents between the liquid mixture and the vapor in equilibrium with that mixture. The more volatile constituents are concentrated in the vapor phase, which is collected after condensation. The effectiveness of the separation is dependent on the physical properties of the... 

The third method that we have used to prepare these diazaboracyclohexane systems is the transamination reaction of 1,3-diaminopropane with the bis(dimethyiamino)boryl compound 8 (eq 8). The solid products 12 and 13, which contain, respectively, two or three of the BN2C3 heterocycles linked by B-N bonds, could not be distilled (or crystallized), but they were thermally stable to at least 200°C. After minor impurities were removed from 12 by vacuum distillation and from 13 by washing with hexane, the structures were confirmed by1H, 13C, and 11B NMR spectroscopy. 

The impure compound, present as a majority in the distillation residue from preparation of 1-diazoindene, will explode if the bath temperature exceeds 120°C [1], A polymer-bound sulfonyl azide reagent has been described as safer in use than the title compound [2], Distillation of the azide at 130-132 C/ 0.5 mbar from an oil bath at 145°C led to darkening, then violent explosion of the 30-40% residue [3],... 

Autofining A fixed-bed catalytic process for removing sulfur compounds from petroleum distillates. This process uses a conventional cobalt/molybdenum hydrodesulfurization catalyst but does not require additional hydrogen. Developed by The Anglo-Iranian Oil Company in 1948. 

Demex [Demetallization by extraction] A process for removing metal compounds from heavy petroleum fractions, after vacuum distillation, by solvent extraction and supercritical solvent recovery. The solvent is typically a mixture of octanes and pentanes. Developed jointly by UOP and the Institute Mexicano del Petroleo seven units were operating in 1988. Hydrocarbon Process., 1988, 67(9), 66. 

Dualayer Gasoline A process for extracting mercaptans and other organic sulfur compounds from petroleum distillates by solvent extraction with aqueous sodium or potassium hydroxide and a proprietary solubilizer. 

Frasch (2) A process for removing sulfur compounds from petroleum fractions by distillation from copper oxide. 

Trickle Hydrodesulfurization A process for removing sulfur-, nitrogen-, and heavy-metal-compounds from petroleum distillates before catalytic cracking. The preheated feed is hydrogenated, without a catalyst, in an adiabatic reactor at 315 to 430°C. Developed by Shell Development Company. As of 1978, 91 units had been installed. 

A Claisen adapter in the distilling flask allows temperature readings to be taken and can help stop your compound from splashing over into the distillation receiver (Fig. 78). Also, you could use a three-neck flask (Fig. 79). Think And, of course, use some glassware too. 

As illustrated for 90 in Scheme 22, different methods were used for the syntheses of compounds 90-92 (91 was prepared according to methods a and b 92 was obtained according to method a). The syntheses of 90-92 were carried out in boiling acetonitrile (in the case of 90 and 91, part of the solvent along with the methanol was removed by distillation). Compound 92 was recrystallized from DMF to give the solvate 92-DMF. Compounds 90-92 and 92 DMF were isolated as crystalline solids. 

Asphalt A sohd residue left after distillation has removed aU other compounds from petroleum. The residue is composed of asphaltenes. 

Although most consumers appreciate the fieriness of chile, capsaicinoids are not perceived through odor or taste receptors but through the nociceptive pain receptors described earlier. The compounds in chile fruit that create the flavor and aroma are produced in the fruit wall. Buttery et al. [90] generated vacuum steam distilled oil from green bell pepper macerate, with well over 40 peaks on subsequent GC/MS analysis. Of these peaks, the major flavor compound associated with bell pepper aroma was 2-methoxy-3-isobutylpyrazine (Fig. 8.1). They also reported several monoterpenoids in abundance, limonene, trans- 3-ocimene, and linalool as well as other aliphatic aldehydes and ketones. The flavor composition of dried red bell pepper powder (sweet paprika) extracted with ether identified 44 key peaks by GC/MS [91]. In these dried samples the key compounds were P-ionone and several furanones. The post-harvest processing and the different fruit maturities as well as possible varietal differences are all causes for the different aromatic profiles. 

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