Refluxing heating

Reaction of 2-(A -allylamino)-3-formyl-4//-pyrido[l, 2-u]pyrimidin-4-ones 219 in EtOH with HONH2 HCI yielded ( )-oximes 220 at 0°C and 221 (R = PhCH2) under reflux. Heating 220 (R = H) in a boiling solvent afforded cw-fused tetracyclic cycloadducts 221 (R = H). In an aprotic solvent (e.g., benzene or MeCN) the main a>fused cycloadducts 221 (R = H) were accompanied by a mixture of trauA-fused cycloadducts 222, A -oxides 223 and tetracyclic isoxazoline 224 (96T887). The basicity of the 2-allylamino moiety of compounds 219 affected the rate of the conversion. Cycloadditions were also investigated in dioxane and BuOH. 

After the addition, reflux heating is continued for two hours, cooling is carried out and there is hydrolysis by the mixture Ice 500 g. Concentrated HCI 200ml. 

Reflux extraction of additives and wax from polyolefins was reported [116]. Subsequently, the additives were adsorbed onto an adsorbent (Florisil) and the wax was removed from the extract before chromatography. Boiling extractions of SBR are described in ASTM D 1416-89 1 g of rubber is extracted by boiling in two 100 mL portions of 75/25 vol% isopropyl alcohol/toluene. Reflux heating with strong solvents, such as THF, dichloromethane or chloroform has been reported [117]. Reflux extraction has also been used for the 3 h extraction of caprolactam and oligomers from PA6 in boiling methanol. 

While the Grignard solution is being refluxed, the dropping funnel is charged with bis(tributyltin) oxide (371 g, 0.62 mol) (Note 1) in 150 mL of anhydrous ether. After the reflux, heating is stopped and the bis(tri-butyltin) oxide solution is added at such a rate as to maintain a reaction temperature of 36-38°C. The addition requires approximately 1 hr. After the addition is complete, the reaction mixture is refluxed for 1.5 hr and then stirred overnight at room temperature. 

After reviewing the literature, the scientist set out on optimization of the first key step, a SnAt reaction. Typical SnAt reaction conditions were initially attempted, examples of which can be seen in Table 8.4. Typical reflux heating in solvents such as DMF and DMSO provided poor yields of the desired products even after prolonged heating. Only with the use of a pressurized vessel were the satisfactory levels of the desired product obtained. However, it should be pointed out that under typical library production conditions, sealed tubes could not be used to produce the desired compounds, and in all actuality the use of refluxing DMSO would also be problematic. After examining... 

Adams cat. pre-hydrogenated platinum dioxide A boiling solvent ( reflux ), heat... 

A suspension of 1.5 g LAH in 150 mL of warm anhydrous THF was stirred under an inert atmosphere and brought up to a gentle reflux. A solution of 2.3 g 1 -(2,5-dimethoxy-4-(n)-propylthiophenyl)-2-nitropropene in 25 mL anhydrous THF was added dropwise at a rate that maintained the reflux. Heating and stirring were continued for 2 days, and then the reaction mixture was allowed to stir at room temperature for an additional 2 days. There was added 1.5 mL Hp (dissolved in... 

Small Quantities. Wear nitrile rubber gloves, laboratory coat, and eye protection. Work in the fume hood. Place 25 mL of concentrated hydrochloric acid in a 100-mL, three-necked, round-bottom flask equipped with a stirrer, water-cooled condenser, dropping funnel, and heating mantle or steam bath. Heat the solution to gentle reflux and add the acrylonitrile (5.3 g, 0.1 mol) dropwise at such a rate to maintain gentle reflux. Heat under reflux while stirring (to prevent bumping) for 5-10 hours. Cool, dilute the reaction mixture with water, and wash down the drain with at least 50 times its volume of water.9... 

Only a few modifications of the algorithm were required to make it applicable to absorption and reboiled absorption. The changes were mainly in the handling of the enthalpy and total mass balance equations to accommodate different specification combinations involving the reflux, heat duties, and top and bottom product flow rates. The results of two example problems, one each for absorption and reboiled absorption, are shown in Table II. 

The preparation reported here produces high yields (98-99% based on BBr3) of pure BMe3 at room temperature in a short time. The need for refluxing, heated catalysts, or extreme conditions is eliminated. 

Minimum theoretical stages at total reflux Heat transferred, Btu/hr Overall heat transfer coefficient, Btu/hrfP°F Vapor velocity, ft/sec Velocity under downcomer, ft/sec Downcomer design velocity, GPM/ft ... 

Amino-1-tetralone (0.62 g, 3.85 mmol) in dry acetone (10 mL) was added to a mixture of NOBF4 (0.59 g, 5.1 mmol) in acetone (10 mL) at -20 °C. After 45 min, more nitrosonium tetrafluoroborate ( 0.67 g, 5.73 mmol) was added to the mixture. The reaction was continued (30 min) until TLC analysis showed no starting material. The mixture was poured into anhydrous CHCI3 (50 mL) and stirred for 30 min. The mixture was dried (MgS04) and the solvent was removed under vacuum. The solids were added portion-wise to a solution of toluene at reflux. Heating was continued for 15 min... 

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