Conversion and selectivity toward

In the lower range of vanadium content, there were little changes of conversion and selectivities between two modified moleclar sieves. However, the conversion and selectivity toward styrene was significatly imprved at higher vanadium content, which is easily obtained by impregnation method. 

The catalytic activity of these supported BF3 samples was tested using the reaction of 1-octene with phenol (performed at 85°C using 0.05 M of each reactant, in 100 ml of 1,2 dichlorethane with lg of supported BF3 catalyst). Table 2 shows the phenol conversion and selectivities towards octyl-phenyl ether obtained after 23 hours reaction time. It is clear that the activity of the BF3(H20)2/SiC>2 catalyst prepared in ethanol is superior to the other samples. The activity can thus be correlated with the number and strength of Bronsted acid sites identified on these catalysts using TGIR. 

Figure 25 Batch reaction conversion and selectivity towards campholenic aldehyde. 

Increasing the pressure from 1 to 12 bar at a constant reaction temperature of 1 200 °C, constant GHSV of 1.17 106 h 1 and constant CH4/02 ratio of two led to lower conversion and selectivity towards hydrogen and carbon monoxide (see Figure 2.19). At a pressure of 12 bar a selectivity of 3% towards ethylene was found. 

Manufacturing of chemical products from selected feed stocks is based on a variety of chemical reactions. The reaction extend is often limited by the chemical equilibrium between the reactants and products, thus reducing the conversion and selectivity towards the main product. The process must then include the separation of the equilibrium mixture and recycling of the reactants. 

As shown in Figure 9, UV-irradiation of Mo-MCM-41 in the presence of a mixture of NO and CO leads to the formation of N2 and C02 with a linear dependence on UV-irradiation time, whereas the turnover frequency exceeds 1.0 after 2h (Tsumura et al., 2000). After 3h, NO conversion and selectivity towards N2 are close to 100%, with only a small amount of N20 formed. Figure 10 shows that there is a good correspondence between the yield of N2 produced and the yield of PL of tetrahedral molybdenum species and the amount of Mo4+ ions generated upon... 

Figure 4. Effect of zeolite crystal size on relationship between methanol conversion and selectivity toward para-xy enQ.

Total conversion and selectivity towards hexanone (HONE) and hexenes (HENES) in the... 

Figure 4. Total conversion and selectivity toward ketone formation for sample D through F.

Conversion and selectivity towards the aldehydes(ketones)in the dehydrogenation of primary... 

Figure 2 a,b 1-butene conversion and selectivity towards cis 2-butene for the Dawson-type heteropolyacid. C,d 1-butene conversion and selectivity towards cis 2-butene for the Keggin-type heteropolyacid. Total flow 10ml min , 20% 1-butene in Helium, 0.3ml catalyst. 

The catalysis occurs in isothermaUy operated continuously stirred tank reactors. The propylene stream (which includes fresh and recycled propylene) is introduced into the reaction stage at controlled conditions, and in excess, to maximize the conversion and selectivity toward PO and to maintain the reaction pressure. 

The first example of supported titanium-catalysed DA reaction was reported by Luis et al. in 1992 (Scheme 7.49). In this work, the authors described the preparation of several polymeric alcohols derived from Merrifield resin and their efficiency as ligand in titanium-catalysed cycloaddition between methacrolein and cyclopentadiene with yields between 83-99% and good exo selectivity. With the aim to evaluate the enantioselectivity of the reaction, catalyst 80 was then prepared almost quantitatively by double esterification of tartaric acid with chloromethylated polystyrene and a 1 1 mixture of titanium tetrachloride/titanium tetraisopropoxide. " Despite the good conversion and selectivity toward the exo-cycloadduct, only 3% enantiomeric excess was recorded, which was attributed to the very high reactivity of the system. Recycling of the catalyst was successfully performed by filtration from the reaction media and washing with dichloromethane, and catalyst 80 was reused seven times without significant loss of catalytic activity. 

Copper(II) chloride not only catalyzes the decomposition of f-BuOOH, but also plays a key role in converting the acetylenic alcohol intermediates to Q , -acetylenic ketones. To obtain both high conversion and selectivity towards o , -acetylenic ketones, optimal reaction conditions are determined to be CuCl2 2H20 alkyne f-Bu00H in a 1 25 50 ratio in t-BuOH at 70 °C under an oxgen atmosphere. The reaction has broad substrate applicability, where R and R can be a variety of aliphatic or aromatic groups (Table 1). 

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