Renewable production of p-xylene from [4 + 2] Diels− Alder cycloaddition of 2,5-dimethylfuran (DMF) and ethylene with H−Y zeolite catalyst in n-heptane solvent is investigated. Experimental studies varying the solid acid catalyst concentration reveal two kinetic regimes for the p-xylene production rate: (i) a linear regime at low acid site concentrations with activation energy Ea = 10.8 kcal/mo...

When mechanical constraints are present, solid-state reactions often induce deviatoric inelastic strains in addition to volume change. Existing models either attribute such deformation to the plastic flow driven by the stress exceeding a non-measurable kinetic-dependent yield strength, or need to introduce a deviatoric-stress-dependent chemical potential. By employing the transformation strain ...

Several kinetic models for the macrocyclization of a C₂ pseudopeptide with a dihalide through a S(N)2 reaction have been developed. These models not only focus on the kinetic analysis of the main macrocyclization reaction, but also consider the competitive oligomerization/polymerization processes yielding undesired oligomeric/polymeric byproducts. The effect of anions has also been included in ...

In the present paper multilane models for vehicular traac are considered. A microscopic multilane model based on reaction thresholds is developed. Based on this model an Enskog like kinetic model is developed. In particular, care is taken to incorporate the correlations between the vehicles. From the kinetic model a uid dynamic model is derived. The macroscopic coeecients are deduced from the u...

in current work a comprehensive mechanism based on intermediate radical termination theory is assumed for raft polymerization of styrene over cumyl dithiobenzoate as raft agent. rate constants for addition (ka) and fragmentation reactions (kf) are set to 6×106 and 5×104 respectively, which lead to an equilibrium constant value of k = ka/kf = 1.2 x 102. moment equations method was used to model ...

A semimechanistic multi-reaction kinetic model was developed to describe the enzymatic hydrolysis of a lignocellulosic biomass, creeping wild ryegrass (CWR; Leymus triticoides). This model incorporated one homogeneous reaction of cellobiose-to-glucose and two heterogeneous reactions of cellulose-to-cellobiose and cellulose-to-glucose. Adsorption of cellulase onto pretreated CWR during enzymatic...

Traditionally, reaction conversion and enantiomeric excess (% ee) of products are monitored using two separate HPLC or GC systems, one system for monitoring the reaction conversion and the other system for determining the % ee. In addition, in-process samples are usually sampled manually, limiting the continuous monitoring of reaction process. For the first time, a fully automated on-line achir...

A kinetic study of the transformation of HGdP2O7.1.5H2O into HGdP2O7.0.5H2O has been achieved by means of isothermal thermogravimetry experiments under controlled water vapour pressure. This pressure was found to have an accelerating effect upon the rate of reaction. The kinetic curves giving the extent of reaction versus time can be described using a Mampel's model. Via this modeling, values o...

the modified surface of typha latifolia l. root (mstl), as an alternative economical adsorbent, wasused for the removal of ni (ii) and cd(ii) ions from aqueous solutions. the effect of initial ph, initialconcentration of metal ion, and contact time was investigated in a batch system at room temperature.the kinetics data could be fitted well by pseudo-second-order model with correlation coeffici...

The solution phase transport and direct electrode kinetics of electro-enzymes are described in terms of a simple model in which the steady state reaction/diffusion equation for enzyme is solved subject to physically realistic boundary conditions. Two physically realizable situations are described: the semi infinite and the membrane bounded case. Limiting expressions for the reaction flux are de...