Glass liners

Preparation of 1 -(/3-D-arabinofuranosyl)-2-thiocytosine A solution of 2.0 g of 1 -(2, 3, 5 -0-triacetyl-/3-D-arabinofuranosyl)-2,4-dithiouracil in 100 ml of methanol is saturated with anhydrous ammonia at 0°C. The mixture, in a glass liner, is heated in a pressure bomb at 100°C for three hours. The reaction mixture is concentrated to a gum in vacuo, and most of the byproduct acetamide is removed by sublimation at 60°C/0.1 mm. The residue is chromatographed on 100 g of silica gel. Elution of the column with methylene chloride-methanol mixtures with methanol concentrationsof 2-25% gives fractions containing acetamide and a series of brown gums. The desired product is eluted with 30% methanol-methylene chloride to give a total yield of 0.386 g (30%), MP 175°-180°C (dec.). Recrystallization from methanol-iso-propanol furnishes an analytical sample, MP 180°-182°C (dec.). 

B) Preparation of 1-0-D-Arabinofuranosylcytosine In a glass liner, a mixture of 1.16 g (3.0 mmol) of 1-(2,3,5-tri-0-acetyl-(3-D-arabinofuranosyl)-4-thiouracil prepared in (A) and about 60 ml of absolute methanol which had been saturated with anhydrous ammonia at 0°C was heated in a steel bomb at 98° to 105°C for 35 hours. After cooling to about 25°C and venting the bomb, the dark solution was filtered into a round-bottom flask. The methanol and excess ammonia were then removed under reduced pressure at about 25°C. The residual syrup was dissolved in absolute methanol, and the methanol was removed under reduced pressure at a bath temperature of about 40°C. This procedure of dissolving in absolute methanol and removing the solvent was repeated, and the residue was held under reduced pressure at a bath temperature of 45°C for 12 hours. 

In Phase 1 (see Figure 2) we used a 300-cc stainless steel pressure vessel, equipped with a l80-cc glass liner. 

In Phase II (see Figure 3) we used a 2900-cc pressure vessel, with a 2000-cc glass liner in which 1000 cc of solution could be polymerized. This was a 10-fold Increase over Phase I. We used a pressure gauge similar to Phase I. There were 5 type J thermocouples. Of these, there were k thermocouples within the reactor as compared to only 1 In Phase I. Two were In the solution within the glass liner, one was between the glass liner and reactor wall, and the... 

The substrate, catalyst and solvent were placed into a glass liner equipped with a magnetic stir bar. The liner was placed in a 250 mL steel autoclave that was then charged at r.t. first with N2, then with H2. The reaction mixture was stirred at r.t. until the hydrogen consumption ceased, after which the H2 was vented, the autoclave flushed with N2 and the reaction mixture filtered off on glass filter. The solution was evaporated and the products crystallized and filtered. The crystalline mixture contained the hydrochloride salt of diamino resorcinol and aniline In order to separate completely diamino resorcinol and aniline, the product mixture has to be recrystallized from hydrochloric acid solution. 

No evidence of ruthenium metal formation was found in catalytic reactions until temperatures above about 265°C (at 340 atm) were reached. The presence of Ru metal in such runs could be easily characterized by its visual appearance on glass liners and by the formation of hydrocarbon products (J/1J) The actual catalyst involved in methyl and glycol acetate formation is therefore almost certainly a soluble ruthenium species. In addition, the observation of predominantly a mononuclear complex under reaction conditions in combination with a first-order reaction rate dependence on ruthenium concentration (e.g., see reactions 1 and 3 in Table I) strongly suggests that the catalytically active species is mononuclear. 

Syngas Homologation of Acetic Acid. To a N2-flushed liquid mix of acetic acid (50.0 gm) and methyl iodide (5.67 gm, 40 mmole), set in a glass liner is added 0.763 gm of ruthenium(IV) oxide, hydrate (4.0 mmole). The mixture is stirred to partially dissolve the ruthenium and the glass liner plus contents charged to a 450 ml rocking autoclave. The reactor is sealed, flushed... 

The reactions with ruthenium carbonyl catalysts were carried out in pressurized stainless steel reactors glass liners had little effect on the activity. When trimethylamine is used as base, Ru3(CO) 2> H Ru4(CO) 2 an< H2Ru4(CO)i3 lead to nearly identical activities if the rate is normalized to the solution concentration of ruthenium. These results suggest that the same active species is formed under operating conditions from each of these catalyst precursors. The ambient pressure infrared spectrum of a typical catalyst solution (prepared from Ru3(CO)i2> trimethylamine, water, and tetrahydrofuran and sampled from the reactor) is relatively simple (vq q 2080(w), 2020(s), 1997(s), 1965(sh) and 1958(m) cm ). However, the spectrum depends on the concentration of ruthenium in solution. The use of Na2C(>3 as base leads to comparable spectra. 

A 10 mL glass liner equipped with a magnetic stirrer bar was dried in an oven at 120 °C overnight, cooled in a desiccator under vacuum and then flushed with nitrogen. 

Glass liner adapted to high pressure reactor with a magnetic stirrer bar... 

A glass liner of a 50 mL hydrogenation bomb was charged with a-acetamido cinnamic acid (240 mg) and a magnetic stirrer bar. The bomb was then assembled, flushed five times with hydrogen (the bomb was pressurized at 200 psi, then the gas inlet was closed before the hydrogen was slowly vented off). 

B. 1,4-Cyclohexanedione. The purified 2,5-dicarbethoxy-l,4-cyclohexanedione (170 g., 0.66 mole) (Note 5) and 170 ml. of water are placed in a glass liner (vented) of a steel pressure vessel of 1.5-1. capacity (fitted with a pressure-release valve). The vessel is sealed, heated as rapidly as possible to 185-195°, and kept at this temperature for 10-15 minutes (Note 6). The reaction vessel is immediately removed from the heater, placed in a large tub of ice water, and cooled to room temperature. The gas pressure then is carefully released. The resulting yellow to orange liquid is transferred to a distillation flask with the aid of a minimum volume of ethanol, and most of the water and ethanol is removed under reduced pressure by means of a rotary evaporator. The flask is attached to a short heated column fitted with a short air condenser. The remainder of the water and ethanol is removed under reduced pressure, and the 1,4-cyclohexanedione is distilled, b.p, 130-133° (20 mm.). The product solidifies to a white to pale-yellow solid, m.p. 77-79°, deld 60-66 g. (81-89% yield from 2,5-dicarbethoxy-l,4-cyclohexanedione). The compound may be conveniently recrystallized from carbon tetrachloride (7 ml. per gram of dione) the purified product is obtained as white plates, m.p. 77-79° (90% recovery). 

The submitters have found that the reaction may be carried out on a much larger scale in an autoclave. The reaction must be run in a glass liner. As the hot reaction mixture is homogeneous, the autoclave may be heated while standing upright. The liner may be filled to three-quarters of its capacity. 

A 600 mL Parr hydrogenation vessel equipped with an injection port with a rubber septum for the addition of the solvent via syringe, a pressure gauge, a tightly fitting removable internal glass liner, thermocouple and an overhead mechanical stirrer was assembled and pressure tested to 14 bar with N2 over... 

The injector can be used in split or splitless mode. The injector contains a heated chamber containing a glass liner into which the sample is injected through... 

The glass liner is slowly contaminated by nonvolatile and decomposed samples and must be replaced periodically. For splitless injection, the glass liner is a straight tube with no mixing chamber. For dirty samples, split injection is used and a packing material can be placed inside the liner to adsorb undesirable components of the sample. 

Figure 6.10. Concentric tube heated injection port with adaptor for 1/8 and 1/4-inch columns. Glass liners are used for all-glass systems.

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