Common solvent

The most common solvent employed is carbon dioxide gas, which can be injected between water spacers, a process known as WaterAlternating Gas (WAG). In most commercial schemes the gas is recovered and reinjected, sometimes with produced reservoir gas, after heavy hydrocarbons have been removed. Other solvents include nitrogen and methane. 

The common solvents available for recrystalhsation are collected in the Table II, 27. 

Tetrachloroethane is a good solvent for many compounds which dissolve only slightly in the common solvents it is, however, inferior in solvent power to nitrobenzene, but, on the other hand, it does not possess oxidising properties at the boiling point. 

In a Lewis-acid catalysed Diels-Alder reaction, the first step is coordination of the catalyst to a Lewis-basic site of the reactant. In a typical catalysed Diels-Alder reaction, the carbonyl oxygen of the dienophile coordinates to the Lewis acid. The most common solvents for these processes are inert apolar liquids such as dichloromethane or benzene. Protic solvents, and water in particular, are avoided because of their strong interactions wifti the catalyst and the reacting system. Interestingly, for other catalysed reactions such as hydroformylations the same solvents do not give problems. This paradox is a result of the difference in hardness of the reactants and the catalyst involved... 

METHOD 2 Speed chemists have used hydroiodic acid (HI) for years to reduce ephedrine to meth. So when the government placed HI on the restricted list, speed chemists took to making the HI themselves. One of the ways they used was to make Hi in DMSO (dimethylsulfoxide, a common solvent) by reacting Nal or Kl with sulfuric acid. This a standard way to make both HBr or Hi in water (see the Chemicals section of this book) except these speed chemists were using the non-aqueous solvent DMSO instead of water. 

METHOD 3 Things start to look easier and the yields higher when the following method is employed [122]. This method uses a solvent called DMSO (dimethylsulfoxide). Maybe you ve never heard of this solvent but Strike has. It is a common solvent used in all fields of science and although Strike is not 100% sure. Strike believes that one can substitute DMF (dimethylformanilide) for DMSO. 

DMSO - Dimethylsulphoxide is a very common solvent with a freezing point of 20 degrees. When you buy this stuff it will be crystallised in the bottle. To melt, all you need to do is place the bottle in a bowl of hot water for 30 minutes - simple. If you re lucky enough to live somewhere warm it may already be liquid, where I live, no chance. When you open the bottle you will notice that this stuff smells a bit farty, don t worry too much, it doesn t get that bad. 500ml straight into the reaction flask and start the stirrer. 

Chloroform - a very common solvent which has a rather unpleasant smell. Try not to get too close to this stuff as it has anaesthetic properties which you don t really want to find out about. 

Because cellulose triacetate has a high softening temperature, it must be processed in solution. A mixture of dichloromethane and methanol is a common solvent. 

Thus far we have assumed that the acid and base are in an aqueous solution. Indeed, water is the most common solvent in acid-base titrimetry. When considering the utility of a titration, however, the solvent s influence cannot be ignored. 

Some solid materials are very intractable to analysis by standard methods and cannot be easily vaporized or dissolved in common solvents. Glass, bone, dried paint, and archaeological samples are common examples. These materials would now be examined by laser ablation, a technique that produces an aerosol of particulate matter. The laser can be used in its defocused mode for surface profiling or in its focused mode for depth profiling. Interestingly, lasers can be used to vaporize even thermally labile materials through use of the matrix-assisted laser desorption ionization (MALDI) method variant. 

The special appeal of this approach is that it allows the heat of mixing to be estimated in terms of a single parameter assigned to each component. This considerably simplifies the characterization of mixing, since m components (with m 6 values) can be combined into m(m - l)/2 binary mixtures, so a considerable data reduction follows from tabulating 6 s instead of AH s. Table 8.2 is a list of CED and 6 values for several common solvents, as well as estimated 6 values for several common polymers. 

Table 8.2 Values of the Cohesive Energy Density (CED) for Some Common Solvents and the Solubility Parameter 6 for These Solvents and Some Common Polymers...

Crystallization and Purification Solvent. Dimethylacetamide is useful ia the purification by crystallization of aromatic dicarboxyHc acids such as terephthahc acid [100-21-0] and/vcarboxyphenylacetic acid [501-89-3]. These acids are not soluble ia the more common solvents. DMAC and dibasic acids form crystalline complexes containing two moles of the solvent for each mole of acid (16). Microcrystalline hydrocortisone acetate [50-03-3] having low settling rate is prepared by crystallization from an aqueous DMAC solution (17). 

Table 10. Chain-Transfer Constants to Common Solvents for Poly(ethyl acrylate) ...

Miscellaneous Pharmaceutical Processes. Solvent extraction is used for the preparation of many products that ate either isolated from naturally occurring materials or purified during synthesis. Among these are sulfa dmgs, methaqualone [72-44-6] phenobarbital [50-06-6] antihistamines, cortisone [53-06-5] estrogens and other hormones (qv), and reserpine [50-55-5] and alkaloids (qv). Common solvents for these appHcations are chloroform, isoamyl alcohol, diethyl ether, and methylene chloride. Distribution coefficient data for dmg species are important for the design of solvent extraction procedures. These can be determined with a laboratory continuous extraction system (AKUEVE) (244). 

LiAlH is soluble in ethers, 35-40 g/100 g diethyl ether at 25°C. Solubihty in THF, the other common solvent for LiAlH, is 13 g/100 g at 25°C. Polyethylene glycol diaLkyl ethers are also good solvents. 

Table 10. Solubilities of Hydrogen Chloride in Common Solvents ...

The symmetrical azonittiles are soHds with limited solubHities in common solvents (54—56). Some commercial aHphatic azo compounds and their 10-h halflife temperatures are Hsted in Table 9. 

The principal route for production of isoprene monomer outside of the CIS is recovery from ethylene by-product C streams. This route is most viable where ethylene is produced from naphtha or gas oil and where several ethylene plants are located in relatively close proximity to the isoprene plant. Although the yield of isoprene per mass of ethylene is quite low, there is enough ethylene produced to provide a large portion of demand. Because of the presence of / -pentane in these streams which a2eotropes with isoprene, extractive distillation must be used to recover pure isoprene. Acetonitrile is the most common solvent, but dimethylformamide is also used commercially. 

MEK is also used iu solvent-based adhesives, iu printing ink formulations, as a solvent iu magnetic tape manufacture, and is the most common solvent used iu dewaxing lubricating oils. Of all these appHcations only an increasing consumption of magnetic tapes is likely to grow ia methyl ethyl ketone use. 

Chain transfer to solvent is an important factor in controlling the molecular weight of polymers prepared by this method. The chain-transfer constants for poly(methyl methacrylate) in various common solvents (C) and for various chain-transfer agents are Hsted in Table 10. 

Possible tape materials include polyimide, polyester, polyethersulfone (PES), and polyparabanic acid (PPA) (18). Of these, polyimide is the most widely used material because its high melting point allows it to survive at temperatures up to 365°C. Although polyester is much cheaper than other materials, its use is limited to temperatures less than 160°C. PES and PPA, on the other hand, are half as cosdy as polyimide, and can survive maximum short-term temperatures of 220 and 275°C, respectively. PES has better dimensional stabiUty than polyimide, absorbs less moisture, and does not tear as easily however, it is inflammable and can be attacked by certain common solvents. Table 7 Hsts various plastic tapes and their properties. Common bump materials are gold, copper, and 95% Pb/5% Sn solder (see Tables 6 and 8 for properties see also References 2 and 21). 

The solubiHty of phosphoms in water is about 3 ppm. However, process water used in phosphoms manufacture or handling often catties larger amounts of phosphoms as particulates or small droplets, depending on the water temperature. Phosphoms-contaminated water is commonly called phossy water. Phosphoms has low solubiHty in most common solvents, but is quite soluble in carbon disulfide and some other special solvents. The solubiHty in CS2 and benzene was formerly used in phosphoms analyses, but toxicity and increasing waste disposal costs have led to mote use of toluene and xylene, and mote tecentiy to the use of nonchemical turbidity measurements. 

Polyester elastomers are resistant to a variety of common solvents including aqueous acids or bases. The chemical resistance of copolyesterether elastomers is shown in Table 13 (193) which gives examples of solvent resistance and is not inclusive. 

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