Simultaneous addition

Fig. II, 13, 9 depicts the use of a two-way adapter arranged for simultaneous addition of a reagent from a dropping funnel and refluxing. An equivalent result may, of course, be obtained by inserting a long-necked, suitably-bent separatory funnel and a condenser through a cork into a flask. The two-way adapter is convenient when a comparatively narrownecked flask is employed.

Others would extend the fertiliser concept to the simultaneous addition of readily biodegradable substrates along with the fertiliser nutrients to stimulate the growth of contaminant-degrading organisms most rapidly, and to aid in the rapid utilisation of the fertiliser nutrients before they might be leached from the contaminated area. The specific requirements for the most efficacious substrates is an area of current research. 

Additions of selected alloying elements raise the recrystaUization temperature, extending to higher temperature regimes the tensile properties of the cold-worked molybdenum metal. The simultaneous additions of 0.5% titanium and 0.1% zirconium produce the TZM aUoy, which has a corresponding... 

The first and third stages involve substitution only whilst the second stage involves simultaneous addition and substitution. 

The simultaneous addition of furfural and sodium hydroxide maintains the concentration of sodium hydroxide at about 2.5%, at which concentration only a small percentage of furfuryl alcohol is formed in the accompanying Cannizzaro reaction. 

These authors have prepared quite a variety of crown-related esters and have incorporated numerous heterocyclic subunits in the macrorings. The structural variety can be gleaned from a perusal of the tables at the end of this chapter. Despite this variety, one basic approach has been utilized in most of the syntheses thus far presented. This method involves simultaneous addition of separate benzene solutions of the diacyl halide and diol to an additional several volumes of benzene heated at 45—60°. After the ad-... 

Finally, it should be noted that at alkaline and neutral pH a concerted mechanism, involving /S-carbon protonation of the enamine and a simultaneous addition of a water molecule, leading to the amino alcohol, can be rejeeted, since the immonium ion appeared to be a real and deteetable intermediate. 

The mechanism of cyclization of diaminopyrimidines by nitrous acid appears not to have been studied in detail. For the preparative procedure an aqueous solution of alkaline nitrite is treated with the diaminopyrimidine either in the form of a salt or with simultaneous addition of hydrochloric or acetic acid. The first phase of the reaction is usually carried out at 0°C, in some cases the reaction being terminated by heating to 50-60°C. With diaminopyrimidines which are sparingly soluble in water, the reaction was carried out in an organic solvent using amylnitrite. Excess nitrous acid can possibly attack the amino groups present. This was employed in some cases for the preparation of the hydroxy derivatives. ... 

The alkylborane is then oxidized by the addition of 150 ml of a 15% solution of hydrogen peroxide, while the pH of the reaction mixture is maintained at 7-8 by the simultaneous addition of 3 Asodium hydroxide, the process being carried out at ice-bath temperature. The reaction mixture is neutralized and subjected to steam distillation. The distillate is extracted with ether, and the extract is dried over anhydrous magnesium sulfate. After removal of the ether, distillation yields 18.0 g (70%) of n-octanal, bp 83-85733 mm. 

Although aluminium is a base metal, it spontaneously forms a highly protective oxide film in most aqueous environments, i.e. it passivates. In consequence, it has a relatively noble corrosion potential and is then unable to act as an anode to steel. Low level mercury, indium or tin additions have been shown to be effective in lowering (i.e. making more negative) the potential of the aluminium they act as activators (depassivators). Each element has been shown to be more effective with the simultaneous addition of zinc . Zinc additions of up to 5% lower the anode operating potential, but above this level no benefit is gained . Below 0 9 7o zinc there is little influence on the performance of aluminium anodes . Table 10.10 lists a number of the more common commercial alloys. 

The examples show Y and W coming from the same molecule, but very often (except in simultaneous addition) they come from different molecules. Also, the examples show the Y—W bond cleaving at the same time that Y is bonding to B, but often (again except for simultaneous addition) this cleavage takes place earlier. 

Dissolution of tellurium in sodium sulphide can be effected only by simultaneous addition of sulphur, when the tellurium will be oxidized to thiotellurite and dissolved . 

Good yields of phosphines have been obtained by the simultaneous addition of an organolithium compound and an alkyl chloride to a solution of a cyclopolyphosphane (6). 

The simultaneous addition of ammonia or amines and carbon tetrachloride to phosphines yields aminophosphonium chlorides (45). 

The use of the triphenylphosphine-carbon tetrachloride adduct for dehydration reactions appears to be a very simple way of synthesizing nitriles from amides, carbodi-imides from ureas, and isocyanides from monosubstituted formamides. All of these reactions involve the simultaneous addition of triphenylphosphine, carbon tetrachloride, and tri-ethylamine to the compound to be dehydrated. The elimination of the elements of water is stepwise. An adduct, e.g. (46), is first formed, chloroform being eliminated, which decomposes to produce hydrogen chloride and the dehydrated product. 

Addition of an alkali metal oxide as a "network modifier to the "network former causes pH sensitivity, i.e., small amounts of alkali metal induce superficial gel layer formation as a merely local chemical attack and so with limited alkali error larger amounts will result in more pronounced dissolving properties of the glass up to complete dissolution, e.g., water-glass with large amounts of sodium oxide. Simultaneous addition of an alkaline earth metal oxide, however, diminishes the dissolution rate. Substitution of lithium for sodium in pH-sensitive glass markedly reduces the alkali error. 

The ICl-CaC03 procedure required a filtration to remove insoluble, inorganic by-products prior to biphasic extraction. In an effort to develop a homogeneous process for the iodination step, a pH control protocol was later implemented in the manufacturing process. The pH-controlled iodination was run in a single phase in a MeOH-water system by simultaneous addition of the aqueous IC1 solution and 1M NaOH. Citric acid was added to increase the buffer capacity to the optimal pH (5-5.5) for robust operation. Under these conditions, the iodoaniline 28 was typically obtained in >99 A% with <1% of diiodoaniline 32. Residual... 

Dynamic immersion challenge Expose sealed containers to periodic challenge by immersion in a suspension of challenge organisms, with simultaneous additional stress of pressure/ vacuum if warranted by the normal conditions of product storage... 

In the reaction of di-(5 -0-monomethoxytrityhmdine-3 -/ -nitrophenylethyl)-pyro-phosphate with a 5 -OH nucleoside component, simultaneous addition of quinoline-8-sulfochloride and 3-nitro-1,2,4-triazole is recommended to obtain a high yield of the fully protected dimer. 1521... 

The edges in a spanning tree are called tree branches or branches. All other edges of G are called chords. Thus, with reference to Tu the chords are 6, 7, 8. Because there is one and only one path between any two vertices of Tj, the addition of any chord to Tx will create exactly one cycle. Such a cycle is called a fundamental cycle. It follows that there are as many fundamental cycles as there are chords (P — N + 1 = C). Thus for the graph in Fig. 1 the fundamental cycles are 3, 4, 6, 2, 4, 7, and 2, 4, 5, 8). Notice that the fundamental cycles are defined only with respect to a given spanning tree. If more than one chord is added to Tx at the same time, cycles which are not fundamental cycles will also be created. For instance, simultaneous addition of chords 7 and 8, will create not only the last two fundamental cycles but also 5, 7, 8 which is not a fundamental cycle. Since each chord occurs only once in a set of fundamental cycles, it should be evident that the rows of a cycle matrix corresponding to the fundamental cycles will be linearly independent and the rank of the cycle matrix will be (P — N + 1). Such a matrix will be referred to as a fundamental cycle matrix. 

Intracerebroventricular infusion of CST-14 dramatically increases the amount of slow wave activity in rats, at the expense of wakefulness. The mechanism by which CST-14 enhances cortical synchronization has been established through the interaction of CST-14 with acetylcholine, a neurotransmitter known to be involved in the maintenance of cortical desynchronization. Application of acetylcholine (ACh) in the anesthetized animal increases fast activity, and this effect is blocked with the simultaneous addition of CST-14. These data suggest that CST-14 increases slow wave sleep by antagonizing the effects of ACh on cortical excitability. In addition to this mechanism, cortistatin may enhance cortical... 

Treatment of the dione dissolved in ethylene glycol-30% hydrogen peroxide with potassium hydroxide leads to a violently exothermic hydrolysis—A-oxidation reaction [1], Simultaneous addition of peroxide and alkali solutions from separate funnels gives a controllable and higher yielding reaction [2],... 

The simultaneous addition of the elastomers and all the compounding ingredients to an internal mixer at the beginning of the mixing cycle. A saving in mixing time is claimed but dispersion may be adversely affected. 

Figure 12.3 Some modes of operation of semibatch reactors (a) addition of a reac-taut (b) removal of a product (c) simultaneous addition and removal...

Although the resulting vinylallenes 48 were usually obtained as mixtures of the E and Z isomers, complete stereoselection with regard to the vinylic double bond was achieved in some cases. In addition to enyne acetates, the corresponding oxiranes (e.g. 49) also participate in the 1,5-substitution (Scheme 2.18) and are transformed into synthetically interesting hydroxy-substituted vinylallenes (e.g. 50) [42], Moreover, these transformations can also be conducted under copper catalysis by simultaneous addition of the organolithium compound and the substrate to catalytic amounts of the cuprate (see Section 3.2.3). 

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