Incompatible salts

Incompat Salts of heavy metals, alkaloids, gelatin, albu -... 

Figure 4.32 shows Janecke diagrams for solutions of a given reciprocal salt pair at different temperatures. These two simple cases will be used to demonstrate some of the phase reactions that can be encountered in such systems. Both diagrams are divided by the saturation curves into four areas which are actually the projections of the surfaces of saturation (e.g., see Figure 4.32b). Salts AX and BY can coexist in solution in stable equilibrium the solutions are given by points along curve PQ. Salts BX and however, cannot coexist in solution because their saturation surfaces are separated from each other by curve PQ. Thus AX and BY are called the stable salt pair, or the compatible salts, BX and A Y the unstable salt pair, or the incompatible salts. In Figure 4.32a the AX-BY diagonal cuts curve PQ which joins the two quarternary invariant points, while in Figure 4.32b curve P Qj is not cut by either diagonal. These are two different cases to consider.

The four salts AX, BY, AY and BX constitute a reciprocal salt pair. One of these pairs, AX, BY or AY, BX is a stable pair (compatible salts), which can coexist in solution, and the other an unstable salt pair (incompatible salts) which cannot (section 4.7.2). 

Care must be exercised in using sodium nitrite near other chemicals. It is incompatible with ammonium salts, thiocyanates, thiosulfates, and strong reducing agents. In acid solutions, sodium nitrite evolves toxic NO in the presence of secondary amines it can form nitrosamines which are suspected carcinogens. 

The basis for the separation is that when two polymers, or a polymer and certain salts, are mixed together in water, they are incompatible, leading to the formation of two immiscible but predominantly aqueous phases, each rich in only one of the two components [Albertsson, op. cit. Kula, in Cooney and Humphrey (eds.), op. cit., pp. 451 71]. A phase diagram for a polyethylene glycol (PEG)-Dextran, two-phase system is shown in Fig. 22-85. Proteins are known to distribute unevenly between these phases. This uneven distribution can be used for the selective concentration and partial purification of the products. Partitioning between the two phases is controlled by the polymer molecular weight and concentration, protein net charge and... 

A WBL can also be formed within the silicone phase but near the surface and caused by insufficiently crosslinked adhesive. This may result from an interference of the cure chemistry by species on the surface of substrate. An example where incompatibility between the substrate and the cure system can exist is the moisture cure condensation system. Acetic acid is released during the cure, and for substrates like concrete, the acid may form water-soluble salts at the interface. These salts create a weak boundary layer that will induce failure on exposure to rain. The CDT of polyolefins illustrates the direct effect of surface pretreatment and subsequent formation of a WBL by degradation of the polymer surface [72,73]. 

As one would expect, in those cases in which the ionic liquid acts as a co-catalyst, the nature of the ionic liquid becomes very important for the reactivity of the transition metal complex. The opportunity to optimize the ionic medium used, by variation of the halide salt, the Lewis acid, and the ratio of the two components forming the ionic liquid, opens up enormous potential for optimization. However, the choice of these parameters may be restricted by some possible incompatibilities with the feedstock used. Undesired side reactions caused by the Lewis acidity of the ionic liquid or by strong interaction between the Lewis acidic ionic liquid and, for example, some oxygen functionalities in the substrate have to be considered. 

An idea of the.diktributibh bf galvanic corrosion in the atmosphere is prp vided by the location of the corrosion of magnesium exposed in intimate contact with steel in the assembly shown in Fig. 19.28 after exposure in the salt atmosphere 25 m from the ocean at Kure Beach, North Carolina, for 9 years. Except where ledges or crevices may serve to trap unusual amounts of electrolyte, it may be assumed that, even with the most incompatible metals, simple galvanic effects will not extend more than about 4-5 mm from the line of contact of the metals in the couple. 

Barium chlorate creates mixtures which are strongly explosive with sulphur or phosphorus. It is incompatible with ammonium salts. Besides, in the presence of sulphuric acid, and like any other chlorate, it forms chlorine dioxide, which detonates at ambient temperature. 

The Polyquats or polymerized quaternary salt. If we study the list of algicides approved by the DETR Committee on pages 107 and 108 in the book Swimming Pool Water published by the Pool water treatment Advisory group, we observe the Polyquats WSCP (or BUSAN 77), WSCP-2 (or BUSAN 79) and APCA (or BUSAN 1055) and their impact on Hazard and Incompatibility data . Indeed, these quats have a very low toxicity and are compatible with most swimming pool chemicals used. 

Table 7.89 lists the main characteristics of MDHPLC (see also Table 7.86). In MDHPLC the mobile-phase polarity can be adjusted in order to obtain adequate resolution, and a wide range of selectivity differences can be employed when using the various available separation modes [906]. Some LC modes have incompatible mobile phases, e.g. normal-phase and ion-exchange separations. Potential problems arise with liquid-phase immiscibility precipitation of buffer salts and incompatibilities between the mobile phase from one column and the stationary phase of another (e.g. swelling of some polymeric stationary-phase supports by changes in solvents or deactivation of silica by small amounts of water).

NaCl or KC1 (Peng et al., 2003 Ballif et al., 2004 Beausoleil et al., 2004 Wilmarth et al., 2004 DeSouza et al., 2005 Vitali et al., 2005) may be used for the SCX fractionation, in spite of the incompatibility of these salts with mass spectrometers. When using KC1, for example, the sample must be desalted off-line (Ballif et al., 2004 Beausoleil et al., 2004), on the RP column before MS/MS acquisition (DeSouza et al., 2005 Vitali et al., 2005), with a vented column (Peng et al., 2003), or with a RP-trap (Vollmer et al., 2004 Wilmarth et al., 2004). The configuration with a RP-trap is shown in Fig. 11.1, and in this case, a flow splitter is used to reduce the flow rate from hundreds of microliters per minute to hundreds of nanoliters per minute. However, HPLC pumps of lower flow rate are now available and could eliminate the need for a flow splitter. 

Silver is incompatible with oxalic or tartaric acids, since the silver salts decompose on heating. Silver oxalate explodes at 140°C, and silver tartrate loses carbon dioxide. 

A mixture of the oxidant and blowing agent (2 1) is used as a dough improver. Potential problems of incompatibility during tableting operations were overcome by incorporating hydrated salts into the tableting formulation. 

Fi-Clor 60S , Brochure NH/FS/67.4, Loughborough, Fisons, 1967 This compound (sodium dichloroisocyanurate), used in chlorination of swimming pools, is a powerful oxidant and indiscriminate contact with combustible materials must be avoided. Ammonium salts and other nitrogenous materials are incompatible in formulated products. The dibromo analogue, used for the same purpose, will behave similarly. 

In the coacervation process, the core substance is first added to a homogeneous solution of the selected solvent and polymer. Mechanical agitation is used to disperse the immiscible core to create tiny droplets suspended in solution (i.e., an emulsion). The coacervation or phase separation phenomenon is then induced by several means, such as changing the temperature and/or acidity of the polymer solution or adding salts, nonsolvents, or incompatible (immiscible) polymers to... 

Dissolve the amine-containing molecule to be thiolated at a concentration of lOmg/ml in cold (4°C) 1M sodium bicarbonate (reaction buffer). For proteins, dissolve them in deionized water at a pH of 7.0-7.5, at room temperature. Note The presence of some buffer salts, like phosphate or carbonate, is incompatible with silver nitrate. 

The mass spectrometer is also incompatible with the HPLC system, but for a different reason. The ordinary mass spectrometer operates under very low pressure (a high vacuum see Chapter 10), and thus the liquid detection path must rapidly convert from a very high pressure and large liquid volume to a very low pressure and a gaseous state. Several approaches to this problem have been used, but probably the most popular is the thermospray (TS) technique. In this technique, the column effluent is converted to a fine mist (spray) as it passes through a small-diameter heated nozzle. The analyte molecules, which must be thermally stable, are preionized with the presence of a dissolved salt. A portion of the spray is introduced into the mass spectrometer. The analyte and mobile phase must be polar if the TS technique is used because the mobile phase must dissolve the required salt and the components must interact with the analyte molecule. See Workplace Scene 13.5. 

The operation of the AX column required aqueous alkaline eluents containing Na2C0.4/NaHCOs. Such an eluent was utterly incompatible for a direct coupling of the LC column with the ESI-MS interface since the inorganic salts crystallised instantly upon entering the ion source. This problem was overcome by placing a cation exchanger before the interface. 

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