Cobalt promotors

The catalyst of choice is cobalt iodide with various promotors from Group 15 elements. The process is mn at 140—200°C, 28—41 MPa (4,000—6,000 psi), and gives an 88% conversion with 90% selectively to acetaldehyde. Neither of these acetaldehyde syntheses have been commercialized. 

The catalyst is a cobalt carbonyl that is prepared in situ from cobaltous hydroxide, and nonylpyridine is the promotor. Oxidation of the aldehyde produces 3-hydroxypropionic acid. 1,3-Propanediol and 3-hydroxypropi-onic acid could also be produced from acrolein (Chaper 8). ... 

Figure 4 The different modes of action of electronic promotors in Co-based Fischer-Tropsch catalysis (A) promoter metal oxide decoration of the cobalt surface (B) the SMSI effect and (C) cobalt-promoter alloy formation...

The molybdate surface layer in the molybdenum-alumina samples is characterized by the presence of BrGnsted acid sites ( 1545 cm- ) and one type of strong Lewis acid sites (1622 cm l). Cobalt or nickel ions are brought on this surface on impregnation of the promotor. The absence of BrtSnsted acid sites is observed for both cobalt and nickel impregnated catalysts, calcined at the lower temperatures (400-500°C). Also a second Lewis band is observed at 1612 cnrl.The reflection spectra of these catalysts indicate that no cobalt or nickel aluminate phase has been formed at these temperatures. This indicates that the cobalt and nickel ions are still present on the catalyst surface and neutralize the Brdnsted acid sites of the molybdate layer. These configurations will be called "cobalt molybdate" and "nickel molybdate" and are shown schematically in Figure 11a. 

A picture has been formed of the way in which the promotor ions are built in the M0O3-AI2O3 system. The neutralization of the Brdnsted acid sites, as originally present in M0O3-AI2O3 systems by the cobalt ions for the catalysts calcined at low temperatures ( 500°C) indicates that the cobalt ions are present on the catalyst surface. The liberation of these sites in catalysts calcined at high temperatures ( 650°C) and the observation of the characteristic reflectance spectrum of C0AI2O4 show that the cobalt ions enter the alumina lattice. However the interaction between cobalt and molybdenum, as indicated by the second Lewis band remains present. This leads to the conclusion that the cobalt ions are present in the surface layers of the alumina lattice. 

Hydrotreating catalysts are usually alumina supported molybdenum based catalysts with cobalt or nickel promotors. By 1990, the demand for hydrotreating catalysts is expected to reach 80,000,000 pounds annually (1). The increased demand for these catalysts and the limitations on the availability and supply of the active metals increase the urgency to develop effective catalyst regeneration techniques. 

At higher temperatures, the influence of phosphorus on the sulfidation of the promotors is completely different. Mangnus et al. 70) reported that the temperature required to obtain complete sulfidation of cobalt in Co—P/Al increases with increasing phosphorus content. The S/Co atomic ratio after sulfidation at 1000°C decreases from 1.3 to 0.39 as a result of phosphorus addition because of the formation of nonsulfided compounds such as cobalt phosphides, according to the following reactions ... 

CoMo HDS catalysts have been extensively studied and it is well known that the active species is molybdenum sulfide and that cobalt is a promotor [3-8], Proper design of the support and adjustment of molybdenum and cobalt composition are very clearly the key points for HDS catalyst design. 

Higher activity catalyst can be achieved by increasing the metal content up to the limit of the support capacity, although the molybdenum efficiency decreases. Consequently, we have worked on the different steps of a catalyst preparation (carrier selection and shaping, Co/Mo ratio, molybdenum and cobalt introduction methods, promotor, thermal and hydrothermal treatments...) and examined the activity of the resulting catalyst at each step. 

Olefins substituted with a cyano group at a remote location carbonylate under conditions similar to an unsubstituted olefin. Thus, heating 3-pentenenitrile in CH3OH at 160°C under 20 MPa CO for 4 hr employing a cobalt acetate and a pyridine promotor, yielded methyl 5-cyanovalerate (98% linear) at 40% conversion . Similar results under similar conditions are obtained with H2C=CHCH(CH3)CN. However, acrylonitrile reacts under milder conditions (125°C, 14 MPa) with ethanol and CO in the presence of Co2(CO)g and a-picoline to give 95% conversion to the a-substituted cyanoester ... 

A comparison of the surface residence times, x, reveals no significant difference for the experiments. From this observation, it can be concluded that the variation in methane 5deld is due to a difference in the amount of active sites. The intrinsic site activity for the methanation reaction remains unchanged after the water treatment, and it is also unaffected by the presence of the rhenium promotor. It is proposed that rhenium supports the reduction of cobalt, but the water pretreatment leads to a reoxidation of the active metal, particularly the fraction of the cobalt metal that is reduced only when rhenium is present. 

Recent patent disclosures by the Standard Oil Co. of Indiana indicate that their process for the polymerization of ethylene is also a relatively low-pressure process, and the following process information is based on these disclosures. The polymerization process is a fixed-bed process employing a prereduced catalyst, ethylene pressures of 809-1,000 psi, and temperatures somewhat greater than 200°C. The metal oxides (such as nickel, cobalt, and molybdenum) can be supported on either charcoal or alumina, and materials such as lithium aluminum hydride, boron, alkali metals, and alkaline-earth hydrides may be used as promotors. Variations of this process are reported to produce polyethylene resins with densities from 0.94-0.97. 

Promoter - mo-tor (14c) (promotor) n. A chemical substance that, in very small concentrating, increases the activity of a catalyst. The promotor may itself be a weak catalyst. Examples in the curing of polyester resins are cobalt octoate used as the promoter with methyl ethyl ketone peroxide, and AT-alkyl anilines used with benzoyl peroxide. 

Interesting news was released by Monsanto [1011, 1012] who reported that they are going to build a large acetic acid plant at Texas City for startup in 1970. Acetic acid will be manufactured by low pressure carbonylation of methanol using a rhodium catalyst together with a halogen promotor [1009, 1010, 1013] instead of cobalt catalyst, which is used in the BASF process. 

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