Glass packed columns

Propylene oxide [75-56-9] M 58.1, b 34.5°, d 0.829, n 1.3664. Dried with Na2S04 or CaH2, and fractionally distd through a packed column (glass helices), after refluxing with Na, CaH2, or KOH pellets. 

Packed Columns A packed column is constructed from glass, stainless steel, copper or aluminum and is typically 2-6 m in length, with an internal diameter of 2-4 mm. The column is filled with a particulate solid support, with particle diameters ranging from 37-44 pm to 250-354 pm. 

Generally, alkan olamines are analyzed by gas chromatography or wet test methods. Details on gas chromatography conditions are available in the fiterature (1) for packed or glass capillary columns. 

The most common chromatogram in the distilled spirits industry is the fusel oil content. This consists of / -propyl alcohol, isobutyl alcohol, and isoamyl alcohol. Other common peaks are ethyl acetate, acetaldehyde, and methanol. The gc columns may be steel, copper, or glass packed column or capillary columns. Additional analyses include deterrninations of esters, total acids, fixed acids, volatile acids, soHds or extracts (used to determine... 

Under typical Hquid-phase chlorination conditions the maximum conversion to benzyl chloride of about 70% is reached after reaction of about 1.1 moles of chlorine per mole of toluene (39). Higher yields of benzyl chloride have been claimed 80% for low temperature chlorination (40) 80—85% for light-catalyzed chlorination in the vapor phase (41) and 93.6% for continuous chlorination above 125°C in a column packed with glass rings (42). 

The checkers found that the distillate contained 15-30% butyraldehyde (as monitored by NMR), which depended upon the efficiency of the distillation, A 10-cm column packed with glass helices was the most efficient, hut the yield of distilled product dropped drastically. 

Note 1). The mixture is heated with a mantle with stirring for 32 hr under a 50-cm fractionating column packed with 5-nm glass beads and topped by a Dean-Stark trap. The reaction mixture is then distilled through the packed column. The fraction which boils at 120 -126°C is collected. The yield is 86.0-87.3 g (77-78%) of 2,2-dimethyl-4-pentenal (1) as a clear, colorless oil, n 1.4216 (Note 2). 

A Vigieux-type column 60 cm. in length and 2 cm. in outside diameter was used for the fractionation. The submitters state that they have also used a column of similar dimensions, packed with glass helices, for a fractionation at atmospheric pressure. They recommended the Vigreux column under reduced pressure, as used by the checkers. 

Calcium oxide. (Preheated to 700-900° before use.) Suitable for alcohols and amines (but does not dry them completely). Need not be removed before distillation, but in that case the head of the distillation column should be packed with glass wool to trap any calcium oxide powder that might be carried over. Unsuitable for acidic compounds and esters. Suitable for drying gaseous amines and ammonia. 

Benzylamine [I00-46-9J M 107.2, b 178 /742mm, 185 /768mm, d 0.981, n 1.5392, pK 9.33. Dried with NaOH or KOH, then distd under N2, through a column packed with glass helices, taking the middle fraction. Has also been distd from zinc dust under reduced pressure. 

HCl, water, 10% aqueous NaHS03, and then water. Dried with CaCl2, Na2S04 or anhydrous K2CO3, and fractionally distd through a Im column packed with glass helices. 

Washed with 10% (vol) aqueous H2SO4 (three times), 10% aqueous KOH (three times), and then with water until neutral. Dried with MgS04 and fractionally distd from CaH2 through a glass helices-packed column under reduced pressure. 

Chlorotoluene [95-49-8] M 126.6, b 159 , d 1.083, n 1.5255. Dried for several days with CaCl2, then distd from Na using a glass helices-packed column. 

Fractionally distd through a 4-ft column packed with glass helices. Ppted as its oxalate from diethyl ether soln. After crystn from 95% EtOH, the salt was decomposed with aqueous saturated NaOH, and the free base was distd, dried over BaO and redistd [McBride and Kruse 7 Am Chem Soc 79 572 1957]. Distn and storage should be under nitrogen. 

Epoxybutane [106-88-7] M 72.1, b 66.4-66.6 , d 0.837, n 1.3841. Dried with CaS04, and fractionally distd through a long (126cm) glass helices-packed column. The first fraction contains a water azeotrope. 

Furfurylamine (2-aminomethylfuran) [617-89-0] M 97.1, b 142.5-143°/735mm, d 1.059, n 1.489, pK3 8.89. Distd under nitrogen from KOH through a column packed with glass helices. 

Steam distd from a soln containing 1-2 equivalents of 20% H2SO4 until about 10% of the base had been carried over with the non-basic impurities, then the acid soln was made alkaline, and the base separated, dried with NaOH and fractionally distd twice. Dried with Na and fractionally distd through a Todd column packed with glass helices (see p. 174). 

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