Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Process equations

As with any first-order process, equation 13.24 can be expressed in an integrated form. [Pg.643]

Although derived for a reversible process, equation 46 relates properties only, irrespective of the process, and therefore apphes to any change in the equiUbtium state of a homogeneous, closed, nonreacting system. [Pg.486]

Process 2 is a single-pressure process, whereas processes 2 and 3 are dual-pressure. The overall process equation can be expressed as NH3 -I- 2O2 —> HNO2 + H2O -I- 412 kJ. Introducing the molecular weights into this equation yields... [Pg.88]

QQ71 It processes equations defined by fault trees, event trees vital area analysis, c non cause... [Pg.132]

Haloforms react with Huonnated alkoxides [4] or phenoxides [5] by carbene processes (equations 3 and 4)... [Pg.447]

It is not appropriate here to consider the kinetics of the various electrode reactions, which in the case of the oxygenated NaCl solution will depend upon the potentials of the electrodes, the pH of the solution, activity of chloride ions, etc. The significant points to note are that (a) an anode or cathode can support more than one electrode process and b) the sum of the rates of the partial cathodic reactions must equal the sum of the rates of the partial anodic reactions. Since there are four exchange processes (equations 1.39-1.42) there will be eight partial reactions, but if the reverse reactions are regarded as occurring at an insignificant rate then... [Pg.81]

Thus, in a reversible process that is both isothermal and isobaric, dG equals the work other than pressure-volume work that occurs in the process." Equation (3.96) is important in chemistry, since chemical processes such as chemical reactions or phase changes, occur at constant temperature and constant pressure. Equation (3.96) enables one to calculate work, other than pressure-volume work, for these processes. Conversely, it provides a method for incorporating the variables used to calculate these forms of work into the thermodynamic equations. [Pg.147]

A few studies have been carried out on the parent four- and five-membered cyclic sulfones—for thietane 1,1-dioxide (30) by Scala and Colon65 and for thiolane 1,1-dioxide (sulfolane) (31) by Honda and coworkers66 and, later, by Schuchmann and von Sonntag67. In the former compound, the major photochemical process, in the vacuum UV range, is the initial production of a trimethylene (C3H6) biradical and S02 (equation 9). In both the solid- (77 K) and gas-phase photolyses, formation of a triplet biradical appears to be favored. As well as the expected cyclopropane and propylene, ethylene is also obtained during these photolyses, presumably by a cycloreversion process (equation 10). [Pg.881]

For an unsteady-state process, equation 10.170 may be solved analyticaly only in the case of a first-order reaction n = 1). In this case ... [Pg.631]

In the discussion of the internal energy U of an ion formed in an ideal stripping process (Equation 13) the quantization of U was not considered. With increasing energy E of the incident ion, the production XH + can be... [Pg.83]

Cell Death. Spontaneous death or sporulation of cells is commonly modeled as a first-order process. Equation (12.8) (or 12.12)) is modified to include a disappearance term ... [Pg.452]

Interrelations Between the Electrokinetic Processes Equation (31.4) for electroosmosis and Eq. (31.10) for the streaming potential, as well as the analogous equations for the other two electrokinetic processes, yield the relation... [Pg.604]

If it is assumed that the total free energy for the transfer of solute X from the gas phase to the stationary phase (with molecular interactions characteristic of Infinite dilution) is the linear sum of the individual free energy contributions to the transfer process then a general expression for the solution process, equation (2.11), can be written as follows... [Pg.101]

Figure 3. Temperature dependence of a width parameter used for sub-glass processes (equation (6)). Figure 3. Temperature dependence of a width parameter used for sub-glass processes (equation (6)).
Treatment of 467 with more than 2 molar equiv of the corresponding aldehyde gives bicyclic products 468 in good yields. These compounds are useful intermediates in the tandem cycloreversion-cycloaddition process (Equation 58) <2000S1170, 2002S 1885>. [Pg.432]

The hydrogenolysis of thiophenes to thiols is a relevant reaction in the HDS process (Equation (16)). [Pg.101]

The absorption spectra of the silicon(IV) naphthalocyanines follows the pattern already seen with the analogous zinc(II) (Section 9.22.12.1.4) and aluminum(III) (Section 9.22.13.2) derivatives 354 the red band is shifted about 100 nm further to the red, with intensification. Bis(trihex-ylsiloxy)silicon(IV) naphthalocyanine has Amax(PhH) = 776 nm (e = 650,000 M-1 cm-1) and <1>A 0.35 (oxygen-saturated benzene).389 The solution is fluorescent (main emission at 780 nm, Tf 2.85 ns) the triplet energy (ca. 22 k cal mol-1) is a little less than the energy of the first singlet state of dioxygen, and the process (Equation (9)) is reversible (cf. compounds (40) and (41), Section 9.22.10.2). [Pg.992]

Solutions containing the [Au(GO)]+ cation are also obtained by treatment of commercial gold(m) oxide AU2O3 with concentrated sulfuric acid in a CO atmosphere. Depending on the reaction conditions, both [Au(CO)]+ and [Au(CO)2]+ are present in these solutions as demonstrated by IR and NMR spectroscopy. The solution catalyzes the carbonylation of terminal olefins and a mechanism has been proposed for the process (Equation (55)). This... [Pg.298]

This approach is based on the assumption that polymer adsorption is fast ("instantaneous") compared with flocculation. In other words the surface coverage is taken to be constant during the flocculation process. Equation (1) states that the flocculation rate tends to zero when 0 tends to 0 or 1. The maximum rate occurs at 0 = 0.5, i.e., at 50% surface coverage. [Pg.430]

The change in Gibbs energy for this process (Equation 17.5) is AG = -27.78 kJ/ mol. This process has a negative AG, meaning that the process is thermodynamically possible and can be a work producer. [Pg.322]

The above definition of the enthalpic effects of conjugation is not unique. A second definition decouples the two double bonds by an alternative hydrogenation process (equation 19). [Pg.76]

Palladium-catalyzed oxidation of hydrocarbons has been a matter of intense research for about four decades. The field was initiated by the development of the aerobic oxidation of ethylene to acetaldehyde catalyzed by palladium chloride and co-catalyzed by cupric chloride (the Wacker process, equation l)1. [Pg.653]

Thermolysis of the syn and anti /J-acetoxy stannanes, obtained by addition of Bu3SnLi to tram- or cis- 1,2-dimethyloxirane and subsequent acetylation, led to (Z)- or (E)-2-butene, respectively, by a stereospecific anti process (equation 34).73. It is postulated that a hyperconjugative interaction of the C—Sn bond facilitates departure of the acetate group in these acyclic systems. The trimethylstannyl and triphenylstannyl analogues likewise undergo anti elimination. [Pg.235]

Trialkyl phosphites readily undergo conjugate addition with a,(3-unsaturated carbonyl compounds in the presence of a proton source, such as a protic solvent.359 The use of a protic solvent, such as an alcohol, obviates the difficulties found in the performance of the simple Abramov-type reaction with a,(3-unsaturated carbonyl compounds.189198 In alcohol medium, an ether is generated as a by-product in the dealkylation process (Equation 3.22). [Pg.63]

In step (1), the solution of equation 9.1-18 requires two boundary conditions, each of which can be expressed in two ways one of these ways introduces die other two rate processes, equating the rate of diffusion of A to the rate of transport of A at the particle surface (equation 9.1-11), and also the rate of diffusion at the core surface to the rate of reaction on the surface (9.1-20), respectively. Thus,... [Pg.231]

Rhodium-catalyzed oxidative C arylations of unprotected pyrroles have been reported, and the products were the result of both arylation and amination processes (Equation (28)).37... [Pg.112]

An ingenious strategy developed by Jun s group makes use of a chelating 3-picolin-2-yl group for performing C-C bond forming reactions. In the particular example shown, for the synthesis of aromatic ketones, methylvinyl ketone is added to suppress unwanted reductive amination processes (Equation (130)). [Pg.141]

A palladium-mediated Stille-C-H functionalization process was recently disclosed. Deuteration of the fused arene led to 92% D-incorporation in the vinylsilane product, suggesting a Pd-migration process (Equation (159)).133... [Pg.149]

Intramolecular C-H arylations have been described and are mediated by a variety of palladium complexes, affording a host of heterocyclic products. Carbazoles can be synthesized by a sequential amination/C-H functionalization process (Equation (161)). [Pg.150]

The hydration of alkynes represents a prime example in which simple coordinative activation by transition metal complexation greatly facilitates an otherwise very slow chemical process (Equation (107)). This reaction has been a long-studied problem, but only recently have alternatives to the classical use of catalysts such as Hg(n) salts been sought. These new catalyst systems typically display much enhanced reactivity, and some can mediate an anti-Markovnikov hydration through a novel mechanism (Table 1). [Pg.678]

Asymmetric induction has also been achieved in the cyclization of aliphatic alcohol substrates where the catalyst derived from a spirocyclic ligand differentiates enantiotopic alcohols and alkenes (Equation (114)).416 The catalyst system derived from Pd(TFA)2 and (—)-sparteine has recently been reported for a similar cyclization process (Equation (115)).417 In contrast to the previous cases, molecular oxygen was used as the stoichiometric oxidant, thereby eliminating the reliance on other co-oxidants such as GuCl or/>-benzoquinone. Additional aerobic Wacker-type cyclizations have also been reported employing a Pd(n) system supported by A-heterocyclic carbene (NHC) ligands.401,418... [Pg.681]


See other pages where Process equations is mentioned: [Pg.226]    [Pg.166]    [Pg.335]    [Pg.80]    [Pg.176]    [Pg.38]    [Pg.600]    [Pg.350]    [Pg.253]    [Pg.350]    [Pg.277]    [Pg.71]    [Pg.301]    [Pg.176]    [Pg.178]    [Pg.200]    [Pg.891]    [Pg.102]    [Pg.657]   
See also in sourсe #XX -- [ Pg.152 ]




SEARCH



© 2024 chempedia.info