Brines unstable

A potentially liazardous by-product of chlorine manufacture is nitrogen trichloride, which is unstable and liigldy explosive. It can be formed from a combination of chlorine with nitrogen compounds in the brine feed, ammonia in... 

A solution of an oxazepinone 6 (0.100 g) and triethyloxonium tetrafluoroborate (1.5 mol equiv) in CH2C12 (10 mL) was stirred in an ice bath for 3 h and then diluted with CH2C12 (50 mL). The solution was washed successively with sat. aq NaHC03 and sat. brine, dried and evaporated in vacuo to give the products in 75-85 % yield as viscous yellow oils. The compounds are unstable and decompose on attempted chromatography. 

The fra/i.s-but-2-cn-1,4-dionc (8.4 mmol) and the methylene compound (8.4 mmol) are stirred with Na2CO, (98 mg) and TEBA-CI (20 mg) in PhH (10 ml) at 75-80°C until the reaction is complete, as shown by TLC analysis (ca. 24 h with P-keto esters and ca. 48 h with cyclohexa-l,3-dione). Et20 (50 ml) is added and the organic phase is washed well with brine. Evaporation of the ethereal solution gives the unstable adduct but, if the etheral solution is saturated with HC1 gas, the adduct is converted into the furan (overall yields >45%). 

Four unstable sulfate esters (373-376) of known furanosesterterpenes were obtained from Ircinia variabilis and from /. or os from the northern Adriatic Sea [328], The 22-O-sulfates of palinurin (377) and fasiculatin (378) were isolated from 7. variabilis and from /. fasiculata respectively. Both were toxic to brine shrimp [329]. Ircinianin sulfate (379) was isolated from /. (Psammocinia) wistarii from the Great Barrier Reef as a very unstable metabolite [330]. 

Threonine and allothreonine are thermally unstable amino acids. The same is true for the simplest hydroxy amino add, (S)-serine (39). High levels of this amino add have however been reported from certain petroleum brine waters and its preservation may be due to the formation of stable chelates. Ahrens has suggested that metal-amino acid chelates may be important in the sedimentary cycle, and the uptake of certain metals in sediments, particularly in binding of metal-amino acid chelates to clays, has been proposed as a possible mechanism for the incorporation of metal ions in carbonaceous materials. Similar complexes are thought to contribute to the stabilization of amino acids in coals, lignites and peats, but, as has been outlined in a previous section, many other ligands are also present in these media, and their relative importance is difScult to assess. Much of this work is unfortunately of a speculative nature since no well-characterized complex of an amino acid has been isolated from a geological source, as far as the author is aware. 

An explanation of why convection occurred when brine formed in the TRS system can be given by interface stability analysis (18). During the experiments, slight tipping of the sample cells indicated that the intermediate brine phases were more dense than the mixtures of liquid crystal and brine below them. This adverse density difference caused a gravitational instability for which the smallest unstable wavelength X is given by... 

In the PDM experiments, no disturbances in the form of brine pockets occurred. Perhaps the smallest unstable wavelength was sufficiently long to prevent their formation. Another possibility is that the high viscosity of the aqueous PDM solutions (over 100 cp (19)) drastically slowed the growth of any disturbances that did form, preventing their detection during the contacting experiments. 

Excess KH in mineral oil is washed three times with dry DMF. under Ar and suspended in 40 mL of DME and then, a solution of 370 mg (1.9 mmol) of allylic alcohol (R)-10 in 10mL of DME is added dropwise. A catalytic amount of 18-crown-6 in 1 mL of DME is added. The mixture is heated under reflux for 3 h and quenched with water. The ethereal extract is washed with brine, dried over Na2S04, and concentrated in vacuo. The crude product is relatively unstable and sensitive to heat. For analysis, it is purified on a short silica gel column to give pure 11 yield 277 mg (75%). 

As discussed previously, petroleum oil reservoirs contain, besides oil, other fluids, and as the pores in the reservoirs are very narrow, thin films of brine or water are formed next to the solid walls. The wettability of the rock changes depending on whether such films are stable or unstable. A relation exists between the capillary pressure and wettability in reservoirs, which has been explored with a simplified version of Equation 5.128 by Basu and Sharma (1996). 

Isol. from the marine cyanobacterium Lyngbya majuscula. Antimitotic agent. Also possesses exceptional brine shrimp toxic and antiproliferative activities. [a]u + 86 (c, 0.64 in CHCI3). Unstable when stored neat. Stereoisomer [157319-51-2]. Curacin B C23H35NOS M 373.602... 

The solubility product of salt changes with temperature and the concentration of the ions present in solution. In oilfield brines, if the surface solubility produced is smaller than their solubility product under down-hole formation, scale formation would occur. Under such conditions, the water is called unstable water. The StabiUty Index (S/) is used to predict the tendency of ions to form scales from oilfield brines which are highly corrosive and encountered during drilling process. The Stiff-Davis Modification of the Langelier equation is used to predict calcium carbonate precipitation from the brines and is given by... 

Brines Used in Frannie Study. Four different brines were used during the laboratory evaluation of polysaccharide and polyacrylamide polymers for the Tensleep reservoir. Frannie injection brine (FIB) was nearly identical in composition to the low-salinity, highhardness reservoir interstitial water. Because FIB was unstable in air owing to the presence of H2S, a chloride-based Frannie injection brine (CBFIB) was formulated as a stable substitute for FIB. Field Madison brine (FMB) was a stable, low-salinity alternative to FIB. Chloride-based enriched Madison brine (CBEMB) was simply FMB saturated with calcium sulfate to simulate the brine that... 

C as compared with 113 C, which is inconsistent with the lower melting point of /S-foim. This is understandable if one determines the temperature dependence of the flexure modulus of a and jS PP by measuring deflection as a fimction of temperature using Perkin-Elmer TMS-2 Thermomechanical Analyser. Fig. 2 shows the deflection of a and fi PP films under a standard loading condition (264 PSI). It can be seen from Fig. 2 that a less pronounced increase of deflection with temperature was observed for PP rather than for oc PP. The reason for the less pronounced decrease of flexure modulus with temperature in jS PP is not known but may be related to the jS-jS recrystallization after the initial melting of the unstable structure. The ff PP has better resistance to many chemicals at temperature up to 100 C than a PP. Chemical resistance tested covers 30 % HCl, concentrated formic acid, concentrated acetic acid, aldehydes, brines, and alkaline solutions. 

The feomdity of polar and sub-polar waters is, in part, explained by the variable sea ice cover. The freezing process enriches the surface water with brine, which renders the stratification of upper ocean layers unstable. This leads to convection and the up-welling of nutrient-rich water to the surface where, in the presence of sunlight, the food chain of plankton-fish-marine mammals is initiated. 

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