Degassing reaction mixture before

A primary compressor increases the pressure of the entering ethylene gas (and propylene gas, which is added as a molecular weight control agent) from between 5 and 15 bar to about 250 bar. The secondary compressor further increases the gas pressure from 250 bar to the desired reactor pressure (approximately 2500 bar). An initiator is added to the gas as it enters the reactor. The reactor is operated to ensure a per-pass conversion of 15%-35% and is a wall-cooled reactor where the cooling water can be used to produce steam. The reaction mixture then enters the HP separator (-250 bar), where the mixture is flashed to produce two distinct phases a PE-rich melt phase and an ethylene-rich gas phase. The separated gas then enters the recycle loop. The ethylene gas is cooled before entering the secondary compressor. The PE enters the low-pressure separator. This low-pressure separator, also referred to as a hopper, performs the final degassing step. The separated ethylene gas is cooled and some components are removed. This step takes place... 

In a second type of experiment, the components used were the same as above in kind, but different in concentrations MMA, O.OIOOM K2S20g, O.OIOOM and NaHS03, O.OIOOM. This reaction mixture, after degassing, was allowed to react for five minutes during which time particles were formed and considerable polymerization took place. The product sol was not dumped into a nitrite/ acid short-stop solution as before, but was simply flocculated with acid. The supernatant serum was then filtered twice. 

The object of the study was a micro-heteropneous polyurethane urea (PUU) based on the prepolymer SKU-PFL-100 (M 1.4 x 10 ), synthesized by the interaction of oli-gotetramethylene oxide diol (M 1 x 10 ) with a double excess of 2,4-toluene diisocyanate. MOCA (aromatic diamine 3,3 -dichloro-4,4 -diaminodiphenyl methane) was used to cme SKU-PFL-100. The NCO/NH2 ratio was 1.2 for this reaction. Piepolymer was degassed at 50 + 10 °C before the reaction. Reaction mixture was stirred for 3 minutes at 50 + 1 °C and a residnal pressure of 1-2 kPa after injection of melted aromatic diamine. Cnring period was 3 days at 80 2 °C. Cured samples were further stored at the room temperature for at least 30 days. 

In a dry reaction vessel, a mixture of l,2-bis[di(4-fluorophenyl)phosphano]benzene (51.8 mg, 0.10 mmol), zinc(II) chloride (a 1.0-M tetrahydrofuran solution, 7.5 mL, 7.5 mmol), and phenylmagnesium bromide (1.17-M tetrahydrofuran solution, 12.8 mL, 15.0 mmol) in toluene (20 mL) is stirred at room temperature for 0.5 h. The resulting suspension is cooled to 0 °C before iron(III) chloride (0.10-M tetrahydrofuran solution, 0.50 mL, 0.050 mmol) and 7-oxabenzonorbomadiene (0.72 g, 5.0 mmol) are added and the reaction is stirred at 0 °C for 2 h. The reaction mixture is quenched with an ice-cooled, degassed solution of 5% acetic acid/methanol and then extracted with n-hexane and 30% diethyl ether/ -hexane, passed through a pad of Florisil, and concentrated in vacuo. The product is obtained as a colorless solid after column chromatography on silica gel (n-hexane/EtOAc, 20 1 Rf = 0.36) 1.02 g (92%). ... 

The most commonly used combination of chemicals to produce a polyacrylamide gel is acrylamide, bis acrylamide, buffer, ammonium persulfate, and tetramethylenediarnine (TEMED). TEMED and ammonium persulfate are catalysts to the polymerization reaction. The TEMED causes the persulfate to produce free radicals, causing polymerization. Because this is a free-radical driven reaction, the mixture of reagents must be degassed before it is used. The mixture polymerizes quickly after TEMED addition, so it should be poured into the gel-casting apparatus as quickly as possible. Once the gel is poured into a prepared form, a comb can be appHed to the top portion of the gel before polymerization occurs. This comb sets small indentations permanently into the top portion of the gel which can be used to load samples. If the comb is used, samples are then typically mixed with a heavier solution, such as glycerol, before the sample is appHed to the gel, to prevent the sample from dispersing into the reservoir buffer. 

For the Al-modification of the PCH, 0.5g is degassed overnight at 200°C before reaction with Al(acac)3 during 1 hour at room temperature in toluene. The concentration of the complex is respectively 25%, 50%, 75%, 100%, 150% and 200% of the silanol concentration of the PCH. After reaction, the mixture has been filtrated and washed with fresh toluene. To remove excess of toluene, the Al-modified PCH is degassed during 4 hours at room temperature. To convert the adsorbed Al(acac)3 into aluminium oxide, a temperature treatment at 550°C during 16 hours (heating rate 2°C/min) was performed. 

---