Silica, as support

Beside SILP experiments with silica as support material, reports have also been made on the use of membranes coated with ionic liquid catalyst solution for the hydrogenation reaction of propene and ethene. The membranes were obtained by supporting various ionic liquids, each containing 16 to 23 mmol Rh(I) complex Rh(nbd)(PPh3)2 (nbd=norbornadiene), in the pores of poly(vinylidene fluoride) filter membranes [118]. 

Liquid/liquid partition chromatography was explored by Willstatter from 1913. The process was extensively developed by Martin and Synge (ca. 1941-1948) who partitioned amino acid derivatives between chloroform and water using precipitated silica as support for the aqueous phase. The preparations of silica were again very variable and it was difficult to prevent adsorption which interfered with the expected behavior of the aminoacids. At first methyl orange was added to the water phase to visualize the amino acids the separation of the acids then caused a red band to move down the columns. The quantitative reaction with ninhydrin was introduced by Moore and Stein in 1948 for both the detection and estimation of the amino acids. Consid-... 

Fe203 and 55 weight % silica, as support, with 1% sodium silicate as a binder. In the preliminary work fly ash was considered as a support material but the maximum amount of iron oxide which could be incorporated with it was 25 weight % Based on this and the other criteria discussed above, the iron oxide-silica composition was found to be the most suitable sorbent for bulk H2S removal,... 

The catalyst was prepared by Johnson Matthey Chemicals pic by an ion-exchange procedure, using SORBOSIL grade AQ U30 silica as support and Pt(NH3)4Cl2 as the source of metal it was reduced in... 

C4C,iin][PF6] [C4C,im][BF4] TMGL MCM-41 mesoporous silica as support 1-hexene as substrate TPPTS as ligand catalyst isolation by centrifugation activity remained stable for at least 11 runs. TOF 87-500 l b 0.7-3.5. [65]... 

More recently, it has been shown that it is possible to extend the methodology for supported aluminium chloride for liquid-phase applications to hexagonal mesporous silicas as supports (HMSs and including MCM materials).115,116 Activity in the alkene alkylation of alkylaromatics is again comparable to that of A1C13 itself, and the solid adds are also easily recovered and can be reused. Most significantly, the increase in selectivity towards monoalkylation through... 

P-22 - Zr-containing hexagonal mesoporous silicas as supports for hydrotreating catalysts... 

For reactions occurring at high temperature, mechum-to-low surface area aluminas are used, which sometimes contain alkali metal cations or silica as support stabilizers, as well as metal activators. 

In the high performance mode, with silica as support for the aqueous stationary phase, Crommen ef al. used naphthalene-2-sulfonate as counter-ion in the separation of alkylamines, amino acids and dipeptides [3]. A pH of 2.3 was used for dipeptides (Figure 7) and the ion-pairs were detectable with high sensitivity in a UV detector because of the UV-absorbing counter-ion. Careful thermostatting was necessary, and eluents with low background extraction of counter-ion were preferred. The response was directly related to the molar absorp-... 

Because these modified systems did not promise new evidence in the basic question of topology but even increased the number of parameters, fiirther work was restricted to the use of pure silicas as support. 

Another possibility is to use silica as support. Shen et al. propose the use of H3PW12O40/MCM-4I supported by impregnation of fluorinated Si-MCM-41 for the selective oxidatimi of alcohols to aldehydes in ionic liquid (IL) medium [63]. The photocatalytic activity of this material was higher than that of bare HPA. Authors observed an optimal loading amount of 30 wt% HPA. The use of... 

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