Drying of solid organic compounds

Drying of recrystallised material, 132 Drying of solid organic compounds, 136, 137... 

Infrared spectra for solid organic compounds are frequently obtained by mixing and grinding a small sample of the material with specially dry and pure potassi um bromide (the carrier), then compressing the powder in a special metal die under a pressure of 15 30 tonnes to produce a transparent potassium bromide disc. As the potassium bromide has virtually no absorption in the middle-infrared region, a very well-resolved spectrum of the organic compound is obtained when the disc is placed in the path of the infrared beam. 

Figure 14.4 Nanofilms for sensing of volatile organic compounds formed from PANI films intercalated with M0O3. (a) Aniline monomer was intercalated within the MoOj film through a cation-exchange process with sodium ions and polymerized with ammonium persulfate. Conductimetric responses to 50 ppm of formaldehyde (b) and acetaldehyde (c) In dry air. (Reprinted with permission from Thin Solid Films, The preparation of polyaniline intercalated Mo03 thin film and its sensitivity to volatile organic compounds by J. Wang, I. Matsubara, N. Murayama et ai. Thin Solid Films, 514, 329-333. Copyright (2006) Elsevier Ltd)...

Solid organic compounds must be dried because the presence of water or organic solvents will affect their weight, melting point, quantitative elemental analysis, and spectra. Since sources of protons must be excluded from some reactions, it is also necessary to remove all traces of moisture or protic solvents from a solid prior to performing such a reaction. 

The second source is process water blowdown, where the water has scrubbed coal-derived gases to remove coal ash and trace components. The raw process water in coal gasification processes contains various organic and inorganic compounds. Purification of this water removes most of the organic compounds, and the plant then recycles much of the water. The net amount of this wastewater effluent reflects the water-soluble inorganics in the feed coal (such as chlorides) and the amount of coal feed. Coal gasification (and direct coal combustion) with dry gas cleanup systems can reduce process water effluents. Coal plants also often use water effluents to control the dust and bulk density of the solid waste. 

The ethereal extracts are then united, dried with a suitable drying agent and filtered. The filtrate is then cautiously distilled, the ether being first distilled and finally the organic compound if volatile if the compound is solid, the crude residue is purified by recrystallisation. Very great care must be taken on all occasions when ether is distilled because of the risk of fire or of an explosion full experimental details for this operation are given, both on p. 8o (Preparation of Ether) and on p. 164 (Pre-... 

Fig. 2. Overall schematic of solid fuel combustion (1). Reaction sequence is A, heating and drying B, solid particle pyrolysis C, oxidation and D, post-combustion. In the oxidation sequence, left and center comprise the gas-phase region, tight is the gas—solids region. Noncondensible volatiles include CO, CO2, CH4, NH, H2O condensible volatiles are C-6—C-20 compounds oxidation products are CO2, H2O, O2, N2, NO, gaseous organic compounds are CO, hydrocarbons, and polyaromatic hydrocarbons (PAHs) and particulates are inerts, condensation products, and solid carbon products.

In a 250 ml Erlenmeyer flask covered with aluminum foil, 14.3 g (0.0381 mole) of 17a-acetoxy-3j5-hydroxypregn-5-en-20-one is mixed with 50 ml of tetra-hydrofuran, 7 ml ca. 0.076 mole) of dihydropyran, and 0.15 g of p-toluene-sulfonic acid monohydrate. The mixture is warmed to 40 + 5° where upon the steroid dissolves rapidly. The mixture is kept for 45 min and 1 ml of tetra-methylguanidine is added to neutralize the catalyst. Water (100 ml) is added and the organic solvent is removed using a rotary vacuum evaporator. The solid is taken up in ether, the solution is washed with water and saturated salt solution, dried over sodium sulfate, and then treated with Darco and filtered. Removal of the solvent followed by drying at 0.2 mm for 1 hr affords 18.4 g (theory is 17.5 g) of solid having an odor of dihydropyran. The infrared spectrum contains no hydroxyl bands and the crude material is not further purified. This compound has not been described in the literature. 

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