Kieselguhr supported

Currently, almost all cumene is produced commercially by two processes ( /) a fixed-bed, kieselguhr-supported phosphoric acid catalyst system developed by UOP and (2) a homogeneous AlCl and hydrogen chloride catalyst system developed by Monsanto. 

For example, while reaction of 2-butoxynaphtalene with copper(II) bromide in benzene at 50°C for 2 h. produced only 6 % yield of l-bromo-2-butoxynaphtalene, similar reaction with Kieselguhr-supported copper(II) bromide gave 86 % yield of the monobromide. On the other hand, reaction using alumina as a support in benzene proceeded completely even at 10°C in 1 h. to give in addition to the monobromide (77 %), the dibromide (21 %) and the binaphtyl (2 %). 

A mixture of 1-methoxynaphtalene (1.90 g, 12 mmol) and Kieselguhr-supported copper(II) bromide (24 g) in benzene (150 ml) was stirred at 30°C for 3 h. The rnixmre was filtered, and the spent reagent was washed with benzene. The combined filtrate was concentrated, and the residue was distilled under vacuum to give 2.3 g (85 %) of 4-bromo-1-methoxynaphtalene. Bp 155-157°C/5 Torr (lit. 159-160°C/5 Torr (ref 15)). 

Fig. 2. (a) Magnetization-volume isotherms for the chemisorption of hydrogen and of benzene on kieselguhr-supported nickel at 150° C (16). (b) Average number of bonds formed by benzene adsorbed on nickel-silica as a function of temperature (17). From J. Amer. Chem. Soc. 79, 4637 (1957) 83, 1033 (1961). Copyright by the American Chemical Society. Reprinted by permission of copyright owner. 

In this connection, it must also be borne in mind that the deoxyribonucleic acids subjected to analysis have probably not been homogeneous. Deoxyribonucleic acids have been fractionated by making use of their different solubilities in normal saline,186 by extracting thymus nucleo-his-tone with sodium chloride solutions of increasing concentration,187 by ion-exchange,187 and also by adsorption of the polynucleotide onto histone immobilized on a kieselguhr support.123 It is possible, however, that these are artefacts, since it has been shown that deoxyribonucleic acid fractions extracted from calf-thymus nucleohistone may or may not vary in composition according to the previous treatment of the material.188... 

Further examples are furnished by the spectra of Figs. 10 and 11. A single pellet of virgin catalyst ( 7 x 10mm) was placed in a cell (Fig. 2) and degassed at room temperature, and spectrum S2 was recorded (the main spectral features are the strong absorptions of the kieselguhr support, but some sulfate absorptions can also be discerned). The catalyst was then exposed to 90 torr of SO2 at room temperature and spectrum was recorded with SO2 in the cell, when new features appeared. 

Novasyn KA constits of kieselguhr supported dimethylacrylamide functionalized with sarcosine methylester. 

The modem process uses a potassium-sulfate-promoted vanadium(V) oxide catalyst on a silica or kieselguhr support. The SO2 is obtained either by burning pure sulfur or by roasting sulfide minerals (p. 651) notably iron pyrite, or ores of Cu, Ni and Zn during the production of these metals. On a worldwide basis about 65% of the SO2 comes from the burning of sulfur and some 35% by the roasting of sulfide ores but in some countries (e.g. the UK) over 95% comes from the former. 

The synthesis of glycopeptides have been performed manually as well as by using automated or semiautomated peptide synthesizers on poly(eth-yleneglycol)-poly(A,A-dimethylacrylamide) copolymer (PEGA) [13,16-22], polystyrene-1% divinylbenzene copolymer [23-37], kieselguhr-supported... 

Catalysts formed by intermetallic compound decomposition show impressive resistance to H2S. Results obtained are shown in Figure 2. It is to be noted that decomposed ThNis is more resistant to poisoning than decomposed ZrNis or the commercial supported nickel catalyst. It is not clear at this time what factors produce these diflFerences. Perhaps the metallic area was smaller for the kieselguhr-supported material it was not determined. The metallic areas of the two decomposed inter-metallics were established and were comparable. 

Product Selectivity. Tables III and IV summarize the product distributions for these catalysts. In Table III the kieselguhr-supported catalysts are compared. From this it is to be noted that the two most active catalysts for CO conversion are, unfortunately, highly selective towards methanation and hence are poor candidates for meeting the desired objective of producing C2-C4 olefins. The Co-Mn catalysts, however, are comparable with the modified Fischer-Tropsch catalyst (Run No. 19), cobalt-copper-thoria, which was prepared as an alkali-free... 

It will be seen that the toxicity increases with the molecular size of the poison. Further, in spite of the obviously far greater specific surface of the 0.05 g. of kieselguhr-supported nickel compared with the surface of the 0.05 g. of unsupported platinum (which is reflected in the different order of the values of a, i.e. 10 and 10 , respectively, in the platinum and... 

The Steps for One Synthesis Cycle for Large-Scale Synthesis on the Polydimethylacrylamide-Kieselguhr Support... 

For early polymerization units, the catalyst was phosphoric acid on a quartz or kieselguhr support. Many of these units were shut down when the demand for gasoline with increased octane numbers prompted the diversion of the olefin feeds to alkylation units that gave higher octane number products. Yet some refinery balances have more propylene than alkylation can handle, so a newer version of polymerization was introduced.It is the Dimersol process of the Institut Frangais du Petrole, for which the flow diagram is shown in Fig. 15.18. 

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