Glacial phase

The glacial phases were events of extreme climatic conditions, manifested by a significant increase in the global snow cover. By how many degrees was the local ambient temperature lower What were the temperatures in the intermediate warmer phases How abrupt were the climatic changes Were there any phases of temperatures higher than the current ones ... 

Demirjian BG, Dosseh G, Chauty A, Ferrer M-L, Morineau D, Lawrence C, Takeda K, Kivelson D, Brown S (2001) Metastable solid phase at the crystaUine-amorphous border the glacial phase of triphenyl phosphite. J Phys Chem B 105(11) 2107-2116... 

Mobile Phase Water Methanol Glacial Acetic Acid (69 28 3)... 

Acryhc stmctural adhesives have been modified by elastomers in order to obtain a phase-separated, toughened system. A significant contribution in this technology has been made in which acryhc adhesives were modified by the addition of chlorosulfonated polyethylene to obtain a phase-separated stmctural adhesive (11). Such adhesives also contain methyl methacrylate, glacial methacrylic acid, and cross-linkers such as ethylene glycol dimethacrylate [97-90-5]. The polymerization initiation system, which includes cumene hydroperoxide, N,1S7-dimethyl- -toluidine, and saccharin, can be apphed to the adherend surface as a primer, or it can be formulated as the second part of a two-part adhesive. Modification of cyanoacrylates using elastomers has also been attempted copolymers of acrylonitrile, butadiene, and styrene ethylene copolymers with methylacrylate or copolymers of methacrylates with butadiene and styrene have been used. However, because of the extreme reactivity of the monomer, modification of cyanoacrylate adhesives is very difficult and material purity is essential in order to be able to modify the cyanoacrylate without causing premature reaction. 

The chloroform solution Is washed with water (2 x 250 ml) and stirred with glacial acetic acid (250 ml) for 1 hr (Note 6). The solution that results Is washed with water (2 x 250 mL), and the chloroform phase is treated with 1.5 L of hexane and kept at 2 C for 48 hr. The material which precipitates Is collected and dried at 0.1 ram In a desiccator (calcium chloride) for 5 hr to give p-methoxyphenyllead triacetate (20-22 g, 35-40%) as pale yellow crystals, mp 138-139°C (Note 7). The product may be kept for at least 3 weeks If stored at 2°C In a sealed container. 

B. Tropohne. In a 1-1., three-necked, round-bottomed flask equipped with a mechanical stirrer, addition funnel, and reflux condenser are placed 500 ml. of glacial acetic acid and then, cautiously, 100 g. of sodium hydroxide pellets. After the pellets have dissolved, 100 g. of 7,7-dichlorobicyclo[3.2.0]hept-2-en-6-one is added and the solution is maintained at reflux under nitrogen for 8 hours. Concentrated hydrochloric acid is then added until the mixture is about pH 1 approximately 125 ml. of acid is required. After the addition of 1 1. of benzene, the mixture is filtered and the solid sodium chloride is washed with three 100-ml. portions of benzene. The two phases of the filtrate are separated and the aqueous phase is transferred to a 1-1. continuous extractor (Note 8) which is stirred magnetically. The combined benzene phase is transferred to a 2-1. pot connected to the extractor and the aqueous phase is extracted for 13 hours. Following distillation of the benzene, the remaining orange liquid is distilled under reduced pressure... 

The first reaction may be carried out either in the liquid or vapour phase although the liquid phase route is now commercially obsolete. In a typical liquid phase preparation, acetylene is passed through an agitated solution of glacial acetic acid and acetic anhydride containing mercuric sulphate, preferably formed in situ, in a finely divided state as catalyst. 

Mobile phase Toluene — ethyl acetate — glacial acetic acid (90 -f 5 -t- 5). 

Mobile phase Methanol — ammonia solution (25%) — glacial acetic acid... 

The organic phase is dried over sodium sulfate and then concentrated to dryness. 1.62 g of the thus obtained crude 1,2a-methylene-6,7a-oxido-A -pregnene-17a-ol-3,20-dione-17-acetate are dissolved in 109 cc of glacial acetic acid. This solution is then saturated at room temperature with hydrogen chloride gas and stored for 20 hours. It is then diluted with methylene chloride and washed with water until neutral. 

Another example of the use of a C8 column for the separation of some benzodiazepines is shown in figure 8. The column used was 25 cm long, 4.6 mm in diameter packed with silica based, C8 reverse phase packing particle size 5 p. The mobile phase consisted of 26.5% v/v of methanol, 16.5%v/v acetonitrile and 57.05v/v of 0.1M ammonium acetate adjusted to a pH of 6.0 with glacial acetic acid and the flow-rate was 2 ml/min. The approximate column efficiency available at the optimum velocity would be about 15,000 theoretical plates. The retention time of the last peak is about 12 minutes giving a retention volume of 24 ml. 

Mobile phase 1. Diethyl ether - glacial acetic acid (20-1-1). 

---