Typical conversions

The MTO process employs a turbulent fluid-bed reactor system and typical conversions exceed 99.9%. The coked catalyst is continuously withdrawn from the reactor and burned in a regenerator. Coke yield and catalyst circulation are an order of magnitude lower than in fluid catalytic cracking (FCC). The MTO process was first scaled up in a 0.64 m /d (4 bbl/d) pilot plant and a successfiil 15.9 m /d (100 bbl/d) demonstration plant was operated in Germany with U.S. and German government support. 

UOP Inc. is the key source of technology in this area, having numerous patents and over 70 units operating worldwide (12). The dehydrogenation catalyst is usually a noble metal such as platinum. Eor a typical conversion, the operating temperature is 300—500°C at 100 kPa (1 atm) (13) hydrogen-to-paraffin feed mole ratio is 5 1. 

Figure 2 shows a simplified flow plan for a typical conversion type refinery. The atmospheric P/S residuum can be fed to a vacuum pipestill. The vacuum tower enables the refiner to cut deeper into the crude, at the same time avoiding high temperatures (above about 750 °F) which cause thermal cracking with resultant deposition of coke and tarry residues in the equipment. 

Conversion of units from one system to another is simply carried out if the quantities are expressed in terms of the fundamental units of mass, length, time, temperature. Typical conversion factors for the British and metric systems are ... 

The hydrothiolation of terminal alkyl alkynes with 96 (Fig. 2.17) proceeds with good degree of regio- and chemo-selectivity, especially with thiophenol and p-methoxy-thiophenol as substrates. Isomerisation to the internal alkenyl thiolates accounts for less than 9% of the thiolated products under the reaction conditions. In addition, further hydrothiolation of the vinyl thioether product is not observed. Typical conversions of 70-85% at 1 mol% loading at 80°C within 5 h are observed. Arylthiols substituted with electron-withdrawing groups afford lower conversions. 

The FTS was conducted at varying temperatures (from 483 to 513 K) over approximately 50 h of reaction time in order to investigate the reaction kinetics achieved with the respective catalysts. A typical conversion curve using the Co/ HB catalyst as an example is shown in Figure 2.3. After a short settling phase (caused by the pore filling of liquid Fischer-Tropsch products) of only about 4 h, steady-state conditions were reached. In the observed synthesis period of 50 h no deactivation of the catalysts was detected. However, industrially relevant experiments over several weeks are still outstanding. 

Similar to nitrogen compounds, electron-rich sulfur compounds, such as the sulfides, with the lone pair of electrons on the sulfur atom, are oxidized to sulfoxides and, further, to sulfones by the H202/titanosilicate sytem (218,232, 233). Table XXXI (232) illustrates typical conversions and product selectivities for various sulfides for the reactions catalyzed by TS-1. Bulky sulfides such as alkyl, phenyl sulfides are relatively unreactive because of their steric exclusion from the pores of TS-1. Diphenyl sulfide could not be oxidized at all. As the diffusivity and, hence, the conversion of the sulfide decreases, the further oxidation of the primary product (sulfoxide) becomes more competitive, leading to increased formation of the corresponding sulfone (Table XXXI) ... 

Various surveys of the literature reveal that on a like-for-like basis a typical conversion may achieve overall energy savings in the range 7-14% within site boundaries (see, for instance, Table 2.2). 

The Pummerer reaction depicted schematically in eq. [132] is a typical conversion in which the chirality at sulfur disappears and a new chiral center on the a-carbon atom to sulfur is created (298). 

Such key features are strongly interconnected via the complex behavior of supported palladium. It is well known that CH4 combustion activity depends markedly on the oxidation state of palladium. In Figure 12.8, a typical conversion curve obtained in temperature-programmed combustion (TPC) experiments during heating/cooling cycles is plotted. 

Figure 7. Typical conversion factors digital dust indicator vs. gravimetric...

In the copolymerization of butadiene or isoprene and styrene, the reactivity ratios are influenced by the type of solvent usedJLi Typical conversion curves of a 75/25 butadiene/... 

The synthesis of pyrrolidines by the free radical transformation of (V-chloroamines, the Hofmann-Loeffler-Freytag reaction, is of preparative significance. The key step is the formation of a radical cation which abstracts hydrogen intramolecularly to form a carbon-based radical (Scheme 21(a)). This species then abstracts chlorine from another TV-chloroamine (60JA1657, 50JA2118). The observed positional selectivity for hydrogen abstraction is a consequence of the preferred adoption of a six-membered transition state. A typical conversion achieved is indicated in Scheme 21(b). 

This is a typical conversion problem in which we want to go from grams of... 

Detailed kinetic studies of some aprotie systems were reported by Bamford s group. The kinetics of the polymerisation initiated by sodium salt of dihydrocinnamic acid in N-methyl-formamide exhibits a few interesting features. Typical conversion curves for D,L-phenyl alanine and y-benzyl-L-glutamate NCA s are shown in Fig. 10 taken from the paper by Ballard and BamfoRD (54). For a low concentration of the salt, the reaction is self-inhibited, i. e. a relatively rapid polymerisation ceases after a while (curve C) when a substantial fraction of the still... 

The position of equilibrium in acetal and hemiacetal formation is rather sensitive to steric hindrance. Large groups in either the aldehyde or the alcohol tend to make the reaction less favorable. Table 15-3 shows some typical conversions in acetal formation when 1 mole of aldehyde is allowed to come to equilibrium with 5 moles of alcohol. For ketones, the equilibria are still less favorable than for aldehydes, and to obtain reasonable conversion the water must be removed as it is formed. 

Preparation and Properties of High-Molecular-Weight Poly (propylene oxide). Figure 4 shows a typical conversion-time plot for polymerization of propylene oxide by a hexacyanometalate salt complex catalyst. This reaction is characterized by an initial period during which almost no conversion occurs, followed by a period of rapid polymerization. The initial period, termed the induction period, is highly... 

A typical conversion-time curve exhibits a short period of acceleration followed by a nearly constant rate up to 50% conversion or more, then followed in turn by a diminishing rate. The acceleration period is sometimes reported to persist to quite high conversion. Although some... 

Figure 1. Typical conversion curves O Process A, Process B, A Process C, A Process D...

A new approach in this area is the synthesis of high purity polycrystalline c-BN sintered bodies [155]. To get a full conversion of h-BN into pure c-BN, pressure and temperature must be relatively high and pure h-BN (<0.03 wt% B203) is necessary. Typical conversion parameters are 7.7 GPa, 1900-2700 °C, and 15 min reaction time. Above 2400 °C no h-BN was observed by X-ray diffraction in the sintered bodies. The c-BN grain size increases from 0.5 pm at 2300 °C to 5 pm at 2700 °C [155],... 

A number of such complexes may be made by oxidizing a solution containing divalent cobalt, together with the appropriate ligand. Other complexes are most easily prepared by substitution of ligands on a complex already formed. The following is a set of typical conversions ... 

Some typical conversion curves are presented in Figure 1 for 33% solids and with between 0.03 and 3.00 percent of sodium lauryl sulfate calculated on the water content. It can be seen that polymerization, essentially to completion, took place rapidly. 

Typical conversions are listed. The same reagents can be used to convert from other ionic forms. Two step regeneration (IXN) is included because of ease of conversion and saving of expensive reagents. 

Birch reduction of aryltrialkylsilanes by lithium-liquid ammonia-ethanol at -70 °C has been studied systematically and a typical conversion is indicated in Scheme 38. ° The major products are usually the... 

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