Mitsuhiro Okimoto

Nickel-catalyzed carbonization of wood for coproduction of functional carbon and fluid fuels I: production of crystallized mesoporous carbon

Japanese larch wood loaded with nickel (1%–4%) alone or with nickel and calcium (0.25%–1.5%) was carbonized at 800°–900°C for 0–120min with a heating rate of 5°–20°C min−1 in a helium flow of 5.8−46.4 ml STP cm−2 min−1 to examine the influence of these variables on the crystallization of carbon (the formation of T component) and the development of mesoporosity. From the obtained results, reaction conditions suitable for effective production of carbon with the dual functions of adequate electroconductivity and adsorption capacity in liquid phase were established, thereby explaining the factors that govern the process. It was also confirmed that mesopore having a diameter of about 4 nm was selectively produced at the cost of specific (BET) surface area in parallel with the formation of T component. This result provided good insight into how the simultaneous dual function could be realized.

Electrochemical Oxidation of Benzylic Amines into the Corresponding Imines in the Presence of Catalytic Amounts of KI

Abstract Oxidation of various benzylic amines using an indirect electrochemical method was successfully carried out under very mild conditions to afford the corresponding imines in good yields. Our results show that, for this electrolytic system, the iodide ions play an important role as electron carriers.

Electrooxidative Conversion of Dibenzoylbenzene Dihydrazones into the Corresponding Bis-diazo Compounds and Bis-dimethyl Acetals

Several dibenzoylbenzene dihydrazones were electrochemically oxidized into the corresponding bis-dimethyl acetals in a methanolic solution containing sodium methoxide and catalytic amount of KI. During electrolysis, the anolyte exhibited a characteristic deep purple, which strongly suggested that formation of a diazo compound as an intermediate. Interestingly, some of the diazo compounds could be isolated directly from the anolyte.

Nickel-catalyzed carbonization of wood for coproduction of functional carbon and fluid fuels II: improved fuel quality of oil fraction and increased heating value of gas fraction

The yields and properties of oil and gas fractions coproduced during carbonization of larch wood loaded with Ni 2%, Ni 2%+Ca 1%, and Ni 4% and without catalyst (None) at 700°–900°C were examined to clarify the catalytic effect in terms of conversion into fluid fuels. The net calorific value of oil occurred mainly below 500°C and increased in the order None < Ni 2% < Ni 4% < Ni 2%+Ca 1%, while the yield decreased in this order. The same order held for the production of gases enriched with hydrogen at 500°–700°C. Even above 800°C, markedly promoted evolution of hydrogen took place for all catalyst systems. These observations confirmed the effectiveness of nickel-catalyzed carbonization at 900°C, particularly Ni 2%+Ca 1%, for both upgrading of oil and gaseous fractions, although the quality of oil was not satisfactory. The catalysis of nickel with and without calcium is discussed on the basis of the modified Broid-Shafizadeh scheme, and the scheme was altered to adapt to the high temperature region where oil was no longer produced.

Electrooxidative Cyclization of Hydroquinolyl Alcohols, Hydroquinolylamines, and Dimethyl Aminomalonates

Several hydroquinolyl alcohols and amines were electrochemically oxidized in methanol in the presence of sodium methoxide and potassium iodide to afford the corresponding intramolecular cyclization products. Furthermore, several amino malonates were electrochemically oxidized to yield the corresponding heterocyclic compounds through an intramolecular carbon–carbon bond formation in the presence of sodium cyanide in methanol.

One Pot Electrooxidative Conversion of Aromatic 1,2-Diketones into Methyl Carboxylates

Abstract One-pot conversion of several aromatic1,2-diketones into the corresponding methyl carboxylates was performed by indirect electrooxidation using iodide ion as an electron carrier in the presence of catalytic amount of sodium cyanide.

Anodic Oxidation of Ketone Allylhydrazones into the Corresponding Azines

Abstract Several ketone allylhydrazones were electrochemically oxidized in methanol in the presence of sodium methoxide and potassium iodide to afford the corresponding azines. The electro-oxidation involves formation of a new carbon–nitrogen double bond between an allylic carbon atom and the nitrogen atom of a hydrazone to afford a conjugated system. Optimal yields were obtained when 0.5 equivalents of sodium methoxide and a catalytic amount of potassium iodide were used as the supporting electrolyte at room temperature. Presumably, the electro-oxidation involves a two-electron oxidation process where the iodide ion functions as electron carrier.

Successful Application of Indirect Electrooxidation for the Transformation of Biaryl Methanols to the Corresponding Biaryl Ketones

Abstract Various biaryl methanols were electrooxidized into the corresponding biaryl ketones in good yields and under very mild reaction conditions. Because of the relatively high oxidation potential, bulky structure, and somewhat poor solubility, biaryl methanols do not readily undergo direct electrooxidative transformations as a synthetic step toward the corresponding biaryl ketones. Herein, we report the successful indirect electrooxidation of secondary biaryl methanols featuring the use of a slight excess amount of KI (1.2 equivalents, relative to the substrate) in MeOH.

One Pot Electrooxidative Conversion of Benzyl Type Alcohols into the Corresponding Methyl Carboxylates

Abstract One-pot conversion of several benzyl type alcohols into the corresponding methyl carboxylates was carried out by indirect electrooxidation using iodide ion as the electron carrier.

One-pot synthesis of 1-arylmethyl-4-[(E)-alk-1-enyl]-1H-1,2,3-triazoles via a cross-coupling/click reaction sequence

1-Arylmethyl-4-[(E)-alk-1-enyl]-1H-1,2,3-triazoles have been synthesized from terminal conjugated (E)-enynes, prepared by copper-mediated cross-coupling reaction of (E)-alk-1-enyldisiamylboranes with (trimethylsilyl)ethynyl bromide, benzyl bromides and sodium azide in a one-pot fashion. In this cross-coupling/click reaction sequence, the copper precursor Cu(acac)2 can serve as a tandem catalyst.