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Repulsive efficiency

Calculate also the activation energy for the reaction, again in kcal/mol, assuming that the Coulomb repulsion maximizes at 3 -y 10 cm separation of the nuclear centers. Assuming a successful cold-fusion device, how many fusions per second would generate one horsepower (1 hp) if the conversion of heat into work were 10% efficient ... [Pg.742]

We found a way to overcome charge-charge repulsion when activating the nitronium ion when Tewis acids were used instead of strong Bronsted acids. The Friedel-Crafts nitration of deactivated aromatics and some aliphatic hydrocarbons was efficiently carried out with the NO2CI/3AICI3 system. In this case, the nitronium ion is coordinated to AICI3. [Pg.200]

Models of a second type (Sec. IV) restrict themselves to a few very basic ingredients, e.g., the repulsion between oil and water and the orientation of the amphiphiles. They are less versatile than chain models and have to be specified in view of the particular problem one has in mind. On the other hand, they allow an efficient study of structures on intermediate length and time scales, while still establishing a connection with microscopic properties of the materials. Hence, they bridge between the microscopic approaches and the more phenomenological treatments which will be described below. Various microscopic models of this type have been constructed and used to study phase transitions in the bulk of amphiphihc systems, internal phase transitions in monolayers and bilayers, interfacial properties, and dynamical aspects such as the kinetics of phase separation between water and oil in the presence of amphiphiles. [Pg.638]

Different samples of aqueous solution containing radionuclides of Co and Eu were prepared at different copper sulphate concentrations and constant polymer concentrations (pAM) of 15 mg/1. The addition of salt to the system was done to reduce both the repulsion forces between the radionuclides and the interaction between the polymeric chains [7]. The polymer efficiency for the prepared samples was determined, results are shown in Fig. 15. It is clear that the polymer efficiency for Eu " is higher than for Co. This can be explained by the difference in the tightly bound structured water associated with different cationic species [14,107]. On this basis, we expect that Co is more hydrated than Eu. This is due to the difference in the ionic size. The hydra-... [Pg.130]

In the case of ions, the repulsive interaction can be altered to an attractive interaction if an ion of opposite charge is simultaneously adsorbed. In a solution containing inhibitive anions and cations the adsorption of both ions may be enhanced and the inhibitive efficiency greatly increased compared to solutions of the individual ions. Thus, synergistic inhibitive effects occur in such mixtures of anionic and cationic inhibitors . These synergistic effects are particularly well defined in solutions containing halide ions, I. Br , Cl", with other inhibitors such as quaternary ammonium cations , alkyl benzene pyridinium cations , and various types of amines . It seems likely that co-ordinate-bond interactions also play some part in these synergistic effects, particularly in the interaction of the halide ions with the metal surfaces and with some amines . [Pg.809]

A highly efficient construction of the steroidal skeleton 166 is reported by Kametani and coworkers111 in the intramolecular Diels-Alder reaction of the a, jS-unsaturated sulfone moiety of 165 (equation 117). Thus, when the sulfone 165 is heated in 1,2-dichlorobenzene for 6h, the steroidal compound 166 can be obtained in 62% yield. The compound 166 produces estrone (167) by elimination of benzenesulfinic acid and subsequent hydrogenation of the formed double bond. The stereoselectivity of the addition reflects a transition state in which the p-tosyl group occupies the exo position to minimize the steric repulsion between methyl and t-butoxy groups and the o-quinodimethane group as shown in equation 117. [Pg.799]

The first summation requires electron repulsion integrals with four virtuaJ indices. Efficient algorithms that avoid the storage of these integrals have been discussed in detail [20]. For every orbital index, p, this OV contraction must be repeated for each energy considered in the pole search it is usually the computational bottleneck. [Pg.42]

Rate of Formation of Primary Precursors. A steady state radical balance was used to calculate the concentration of the copolymer oligomer radicals in the aqueous phase. This balance equated the radical generation rate with the sum of the rates of radical termination and of radical entry into the particles and precursors. The calculation of the entry rate coefficients was based on the hypothesis that radical entry is governed by mass transfer through a surface film in parallel with bulk diffusion/electrostatic attraction/repulsion of an oligomer with a latex particle but in series with a limiting rate determining step (Richards, J. R. et al. J. AppI. Polv. Sci.. in press). Initiator efficiency was... [Pg.365]

Several ways to suppress the 2-oxonium-[3,3]-rearrangements might be envisioned. Apart from the introduction of a bulky substituent R at the aldehyde (Scheme 23) a similar steric repulsion between R and R might also be observed upon introduction of a bulky auxiliary at R. A proof-of-principle for this concept was observed upon by using of a trimethylsilyl group as substituent R in the alkyne moiety (Scheme 25, R = TMS). This improvement provided an efficient access to polysubstituted dihydropyrans via a silyl alkyne-Prins cyclization. Ab initio theoretical calculations support the proposed mechanism. Moreover, the use of enantiomerically enriched secondary homopropargylic alcohols yielded the corresponding oxa-cycles with similar enantiomeric purity [38]. [Pg.17]

Within our approach the entire molecnlar symmetry is exploited to increase the efficiency of the code in every step of the calcnlation. For a molecule belonging to a group G of order G, only 7v /(8 G ) symmetry-distinct two-electron integrals over a basis set of J f Ganssian atomic fnnctions are calcnlated and processed at each iteration within SCF, first- and second-order CHF procednres. A skeleton Conlomb repulsion matrix is obtained by processing the non-rednndant list of nniqne two-electron integrals, then the actual repulsion matrices G , a < /7, are obtained via the equation... [Pg.289]

Thus we have found that the screening should be more efficient than in the Debye-Hiickel theory. The Debye length l//c is shorter by the factor 1 — jl due to the hard sphere holes cut in the Coulomb integrals which reduce the repulsion associated with counterion accumulation. A comparison with Monte Carlo simulation results [20] bears out this view of the ion size effect [19]. [Pg.110]

A novel approach [98], proposed for generating starting configurations of amorphous dense polymeric systems, departs from a continuous vector field and its stream lines. The stream lines of continuous vector fields never intersect. If the backbones of linear polymer chains can be associated with such stream lines, the property of the stream lines partly alleviates the problem of excluded volume, which - due to high density and connectivity - constitutes the major barrier to an efficient packing method of dense polymeric systems. This intrinsic repulsive contact can be compared to an athermal hard-core potential. Considering stream lines immensely simplifies the problem. [Pg.59]


See other pages where Repulsive efficiency is mentioned: [Pg.2365]    [Pg.2382]    [Pg.2521]    [Pg.2835]    [Pg.308]    [Pg.56]    [Pg.312]    [Pg.402]    [Pg.448]    [Pg.355]    [Pg.2014]    [Pg.96]    [Pg.1104]    [Pg.22]    [Pg.193]    [Pg.809]    [Pg.563]    [Pg.3]    [Pg.119]    [Pg.186]    [Pg.233]    [Pg.237]    [Pg.265]    [Pg.563]    [Pg.27]    [Pg.32]    [Pg.174]    [Pg.73]    [Pg.1]    [Pg.311]    [Pg.312]    [Pg.242]    [Pg.4]    [Pg.413]    [Pg.42]    [Pg.478]    [Pg.481]   
See also in sourсe #XX -- [ Pg.177 ]

See also in sourсe #XX -- [ Pg.177 ]




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