Fortuitous water

In an extension to this work it was found that simple metal halides (and some carbonyls) could also form liquid clathrates with [18] crown-6 in toluene or benzene when HC1 was bubbled through the mixture, but only in the presence of trace water (or fortuitous water , as it became known within the group) [4]. These systems also generated hydronium ions that were stabilized by the crown ether and crystallized from solution. 

The earlier interpretation of point X in terms of a close-packed monolayer of water would thus seem untenable. As has been clearly demonstrated, the total uptake at X, 327pmolg" , contains a contribution of ISOpmolg" from chemisorption thus physisorption accounts for only 177pmolg, which corresponds to 21 h per molecule of water. The fact that the total uptake at X corresponds to 11-2A, and is therefore close to the figure 10-5 for a close-packed monolayer, must be regarded as fortuitous. 

To be effective, there must be a certain minimum concentration of inhibitor at the interface to be protected. Therefore, there must be sufficient inhibitor in the primer, and these inhibitors need to be soluble enough in water to enable transport of inhibitor to the oxide surface as water permeates the adhesive joint. However, too high of a solubility will rapidly deplete the primer layer of inhibitor resulting in a loss of protection. One of the fortuitous properties of zinc and strontium chromates is the limited solubility of these compounds in water (about 1.2 g/1 at 15°C [33]). 

As shown in Figure 3.6-1, GC and Pt exhibit anodic and cathodic potential limits that differ by several tenths of volts. However, somewhat fortuitously, the electrochemical potential windows for both electrodes in this ionic liquid come out to be 4.7 V. What is also apparent from Figure 3.6-1 is that the GC electrode exhibits no significant background currents until the anodic and cathodic potential limits are reached, while the Pt working electrode shows several significant electrochemical processes prior to the potential limits. This observed difference is most probably due to trace amounts of water in the ionic liquid, which is electrochemically active on Pt but not on GC (vide supra). 

The subsequent advance was rather fortuitous and rested more with serendipity than with scientific logic. A search was made for cheaper more effective replacements for casein hydrolysate. Amongst the tested materials was com steep liquor (CSL). CSL is a by-product of the manufacture of starch from maize kemals. Whole maize is incubated in warm water, at 50°C acidified with SO2. Thermophilic bacteria hydrolyse proteins and other components of the kemals, thereby loosening the starch granules. These are removed, leaving behind the steep liquor which is used to treat further maize kemals. Ultimately, the liquor is too viscous to re-use and the liquor is concentrated and used as cattle feed. It was this material that was used for penicillin fermentation. Surprisingly, the yield of penicillin increased by a further 5-10 fold giving yields of 50-100 ig ml. 

Cisplatin was discovered fortuitously by observing that bacteria present in electrolysis solutions could not divide. It is hypothesized that in the intracellular environment, a chloride is lost and replaced by a water molecule. The resulting species is an efficient bifunctional interactor with DNA, forming platinum-based cross-links similar to that formed by alkylating agents. 

Algal blooms in fresh water ponds occasionally poison livestock and waterfowl. Axenic cultures of Anabaena flos-aquae NRC 44-1 were shown to produce the toxic principle (5) which can be present in the algae and in the water of mature cultures (6). The discovery of the toxin was fortuitous in the sense that AChR agonists do not have a (known) constructive function in the algae evolution of the synthetic pathway was likely a by-product of metabolic pathways in the algae. The compound became evident only through its toxic effects on other organisms. 

It is in many ways unfortunate that the study of cationic polymerization has, from its very start, been so intimately linked with the very complicated and ill-understood chemistry of the metal halides. This connection is largely fortuitous and there is the promise of much progress in this field when these two problems can be attacked independently. On the one hand, we need to know much more about the complex acids and esters which are formed when water, alcohols, carboxylic acids, and alkyl halides react with metal halides on the other hand, a study of olefin polymerizations catalysed by simple acids such as HBr [14], HC104 [25], and H2S04 [26] should be rewarding, because they would presumably be unobscured by the complications and uncertainties accompanying the formation of the initiating species when this involves a metal halide. 

Based on cp-AFM evidence for the simple case of an n-alkanethiolate/Au SAM, the M structures show no evidence for penetration of metal to form conducting filaments that can cause shorts. The resultant junctions, however, do show extensive formation of reaction product layers with complex chemical compositions which may lead to unfavorable characteristics for molecular device operation. Indeed, in recent reports the use of Ti deposition on LB films, which contain water and inorganic salts at the bottom Pt electrode/LB film interface, leads to formation of inorganic titanium oxide type species in the junction but these complex inorganic layers have also been reported to impart fortuitously quite useful device... 

As in the ethylene oxide system kinetics are complex and do not lend themselves to exact interpretation (19). The boron fluoride — water catalyst system appears to be most effective at a boron fluoride/water ratio of about three, a surprising and probably fortuitous similarity to the efficiency of this catalyst in the isomerization of some hydrocarbons (20). At low water concentrations the number of polymer molecules formed equals the number of water molecules added and chain transfer may be assumed, though it has not actually been demonstrated. There is some indication of a maximum molecular weight of 15,000—20,000 at — 20° C but the present data are inadequate to establish this point. The order in monomer appears to be first at low water concentrations rising to second at higher water levels, but it seems quite possible that this apparent change in order is due to some factor such as catalyst destruction. 

Thomas and Webb (129), using an emulsion polymerization model, calculated k2 from Rp and the number of particles. Their value at room temperature was 2 x 104 1 m-1l-1, in good agreement, perhaps fortuitously, with Dainton and Eaton (49). This treatment assumes that the monomer water ratio at the particle is the same as in the continuous phase. If allowance were made for adsorption of monomer this value of k2 would fall to approach more closely the level observed in DMF. 

Lastly, besides inconsistency in the polymer and additives, there may be fortuitous differences between mixes of what supposedly is the same composition—such as the water content changing between summer and winter (or by night and day under some climatic conditions). Thus, provision must be made for drying and the removal of other volatiles, and (especially if the processing is by batches and components are held in store at intermediate stages) drying may be required at more than one point in the manufacture. 

A -tetrahydrocannabinol is a liquid and is highly insoluble in water (8-10). This can be a critical factor in its bioavailability, pharmacokinetics and pharmacological action. Large differences in the bioavailability of tetrahydrocannabinol from various solutions and administrative routes have been reported (9,10). Evidence has been presented (8) that tetrahydrocannabinol s solubility may be exceeded in plasma, resulting in its possible precipitation and fortuitous localized accumulation in body organs. 

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