Various π-conjugated polymers have been obtained by using organometallic polycondensations mediated by organotransition metal complexes. For example, Ni(0) complex-promoted dehalogenation polycondensation of dihaloaromatic compounds X–Ar–X affords poly(arylene)s,n. Pd-catalyzed polycondensation gives poly(arylene–ethynylene)s,n. These polymers are electrochemically active, electrically conductive, and light-emitting. Their well-characterized linear structure brings about unique packing of the polymer molecules in the solid. In this paper, we describe preparation by the organometallic polycondensations, basic properties, the ordered structure in the solid, and applications for electronic and optical devices of π-conjugated polymers.rr–C≡C–Ar′–C≡C

π-Conjugated Polymers Bearing Electronic and Optical Functionalities. Preparation by Organometallic Polycondensations, Properties, and Their Applications

The dehydrogenation of propane to propene in the presence of carbon dioxide has been carried out over unpromoted and potassium promoted Ga2O3 catalysts. It was found that carbon dioxide enhance the initial activity of the Ga2O3 catalyst. After 0.2 h of reaction periodic propane conversion and propene selectivity reach 33 and 93%, respectively, while in the presence of argon only 25% conversion and 90% selectivity are achieved under the same condition.

Dehydrogenation of propane to propene over gallium oxide in the presence of CO2

This review is a summary of the work done and potential opportunities for inexpensive and easily accessible base catalysts, such as alkaline earth metal oxides and hydroxides, as well as alkali metals and oxides supported on alkaline earth metal oxides Preparation methods of these materials, as well as characterization of basic sites are reported An extensive review of their catalytic applications for a variety of organic transformations including isomerization, carbon–carbon and carbon–oxygen bond formation, and hydrogen transfer reactions is presented

Optimization of Alkaline Earth Metal Oxide and Hydroxide Catalysts for Base-Catalyzed Reactions

The condensation and selective hydrogenation of acetone to methyl isobutyl ketone (MIBK) was studied on a directly comparable series of 0.1–1.5 wt% Pd and Pt catalysts supported on hydrotalcite (HT)-derived Mg Al mixed-oxides in a liquid-phase batch micro-reactor at 99–153 °C and 400 psig. The support catalyzes the condensation of acetone to diacetone alcohol (DAA) and its subsequent dehydration to mesityl oxide (MO); Pd and Pt catalyze the selective hydrogenation of MO to MIBK. The net yield of MIBK is independent of metal type and loading, depending only on the wt% of exposed metal. However, the by-products are quite different-Pt/HT is more selective for the direct hydrogenation to isopropanol (IPA) while Pd/HT forms more of the intermediate diacetone alcohol (DAA). Among the Pd- and Pt-based catalysts examined, the 0.1 wt% Pd/HT gives the maximum MIBK yield of ∼32%, with an unusually low selectivity to IPA, 0.6 mol% compared to 15 mol% for the next best catalyst. This appears to be due to its higher basicity, and (to a lesser extent) to its minimal concentration of metal sites. This metal loading is sufficient to fully hydrogenate mesityl oxide to MIBK, and it also shows minimal acetone hydrogenation to isopropanol. A study of physically mixed Pd/silica + HT versus Pd/HT shows that the acid/base and hydrogenation functions need not be molecularly close.

Acetone condensation and selective hydrogenation to MIBK on Pd and Pt hydrotalcite-derived MgAl mixed oxide catalysts

The use of CO2 as feedstock for producing chemicals is not only interesting to contribute to mitigation of greenhouse gas emissions, but an interesting challenge to explore new concepts and new opportunities for catalysis and industrial chemistry. The present state and perspectives in heterogeneous catalytic reactions with CO2 are briefly surveyed both in terms of (i) use of catalysis for CO2 fixation and (ii) use of CO2 in heterogeneous catalytic reactions as mild oxidant, H-transfer agent and catalyst surface modifier. Discussion is limited to heterogeneous gas-solid catalytic reactions. Some results and opportunities for gas-phase photoelectrocatalytic conversion of CO2 to fuels (hydrocarbons and alcohols) are also shown.

Heterogeneous Catalytic Reactions with CO2: Status and Perspectives

One step synthesis of MIBK from acetone over Ni/CaO catalysts was studied. 10 wt% Ni/CaO catalysts were prepared by conventional impregnation method (catalyst I), and liquid phase oxidation method using NaOCl as an oxidant (catalyst L). Catalyst L showed much higher activity than catalyst I because of recovered CaO pore structure and high BET surface area. Catalyst C, prepared by coprecipitation method, showed 60% of MIBK selectivity with a fairly high overall acetone conversion. Catalysts L and C had two CO2 desorption states (α, Β). Incorporated Ni enabled support precursor [Ca(CO)3] to decompose easily into CaO andCO2even at low temperature and generated weakCO2desorption state (α) which was from active state.

One step synthesis of mibk (methyl isobutyl ketone) from acetone over CaO-supported Ni catalyst

2wt% Ni-CaO catalyst prepared by sol-gel process showed 70-80% acetone conversion and 60% MIBK selectivity at 200 °C of reaction temperature. The incorporated Ni influenced CaCO3, catalyst intermediate, to readily decompose into CaO, active basic component, and CO2 at even 500 °C. Meanwhile, Co or Pd did not influence CaCO3 decomposition at the same temperature of 500 °C and showed no catalytic activity. That is, Ni played a role as promoter for catalyst activation as well as active site of hydrogenation.

A New Active Catalyst for Single Step Synthesis of Methyl Isobutyl Ketone from Acetone

A study on the alkali metal-promoted magnesium oxide system used as a catalyst for acrylonitrile synthesis from methanol and acetonitrile

The catalytic behavior of magnesium oxide doped with potassium oxide was investigated for acrylonitrile formation from acetonitrile and methanol. CO2 was applied as a mild oxidant. Under this oxidative condition, the reaction proceeded via an oxidative dehydrogenation pathway resulting in the increase of both acetonitrile conversion and acrylonitrile selectivity compared with the reaction under a non‐oxidative condition.

Effect of CO2 addition as an oxidant on the catalytic activity of K/MgO for acrylonitrile synthesis

One step synthesis of MIBK (methyl isobutyl ketone) from acetone over co-impregnated Ni-CaO catalyst and Ni effect on the thermal decomposition of CaCO 3 into CaO were studied. Bulk calcium acetate, one of catalyst precursors, decomposed into CaCO 3 and acetone at 400-450 °C, and CaCO 3 into CaO and CO 2 at 700 °C But, when nickel acetate for 2 wt% Ni was added into calcium acetate, the decomposition temperature of CaCO 3 was decreased to 500 °C in H 2 /N 2 stream but not in O 2 /N 2 stream or air, and in case of 20 wt% Ni, this phenomenon was more drastic. From TPD-MS experiment, we found out that Ni-added CaCO 3 did not decompose directly into CaO and CO 2 but via the route of CaCO 3 + 4H 2 → CaO + CH 4 + 2H 2 O, supposed to have a relatively low activation barrier. CaO can be formed even at 500 °C with the aid of Ni and H 2 . When 2 wt% Ni-CaO reduced at 500 °C for one step synthesis of MIBK was used, 60 – 80% of acetone overall conversion and 50 – 60% of MIBK selectivity were obtained.

Jin Mok Hur

Papers

One step synthesis of mibk (methyl isobutyl ketone) from acetone over CaO-supported Ni catalyst

A New Active Catalyst for Single Step Synthesis of Methyl Isobutyl Ketone from Acetone

A study on the alkali metal-promoted magnesium oxide system used as a catalyst for acrylonitrile synthesis from methanol and acetonitrile

Effect of CO2 addition as an oxidant on the catalytic activity of K/MgO for acrylonitrile synthesis

Preparation and Characterization of Ni-CaO Catalyst for One Step Synthesis of MIBK (Methyl isobutyl ketone) from Acetone