Oxides, Hydroxides, and Aluminosilicates

Soils formed in volcanic ejecta have many distinctive physical, chemical, and mineralogical properties that are rarely found in soils derived from other parent materials. These distinctive properties are largely attributable to the formation of noncrystalline materials (e.g., allophane, imogolite, ferrihydrite) containing variable charge surfaces, and the accumulation of organic matter. Formation of noncrystalline materials is directly related to the properties of volcanic ejecta as a parent material, namely the rapid weathering of glassy particles. The composition of the colloidal fraction forms a continuum between pure Al–humus complexes and pure allophane/imogolite, depending on the pH and organic matter characteristics of the weathering environment. For soil management purposes, volcanic soils are often divided into two groups based on the colloidal composition of the surface horizons: allophanic soils dominated by allophane and imogolite, and nonallophanic soils dominated by Al–humus complexes and 2:1 layer silicates. Volcanic soils exhibit a wide range of agricultural productivity, depending on the degree or intensity of pedogenic development and the colloidal composition of the rooting zone. The different charge characteristics of allophanic and nonallophanic soils is the most important factor regulating chemical fertility attributes. Phosphorus fixation, strong acidity, and aluminum toxicity are the primary chemical limitations to agricultural productivity. Volcanic soils generally have high physical fertility (tilth) and mature soils are relatively resilient to erosion and compaction. To maximize the productivity of volcanic soils, proper management based on an understanding of the unique physical, chemical, and mineralogical properties of these soils must be practiced.

The Nature, Properties and Management of Volcanic Soils

The discovery of simple and efficient catalyst systems for the asymmetric oxofunctionalization of hydrocarbons is a challenging task of catalytic chemistry. In this paper, we give an overview of catalyst systems capable of conducting asymmetric oxygenative transformations of organic molecules and, in line with the major trend to sustainability, relying on green oxidants H2O2 and O2 as the ultimate oxygen source. The full historical period of asymmetric oxidation catalysis (1970 to the present day) is covered; both transition-metal-based and organocatalytic systems are considered. The focus of this review is the catalytic properties of the existing catalyst systems, in particular stereoselectivity, activity, efficiency, and synthetic outlook. At the same time, mechanistic peculiarities of stereoselective oxygen transfer are given attention.

Catalytic Asymmetric Oxygenations with the Environmentally Benign Oxidants H2O2 and O2.

Most soils derived from volcanic ash and pumice show distinctive properties that are not found in soils derived from other parent materials under the same vegetation and climate. Thorp and Smith (1949) first recognized them as a great soil group and gave them the tentative name Ando soils; Ando means dark soils in Japanese. They noted a wide distribution of these soils in deposits of volcanic ash not only in Japan but in other parts of the world. The Ando soils consist, primarily, of dark brown to black A1 horizons, averaging about 30 cm thick, of fine crumb or granular structure with the organic content close to 8% on average and ranging up to 30% in the darkest members of the group. Some members of the group have distinct B horizons with more clay than A horizons, but the younger members are essentially AC soils. The soils have low exchangeable “bases” and occur in humid to perhumid climates with temperature efficiency ranging from cool mesothermal to tropical. Natural vegetation varies from place to place and includes broad-leaved and coniferous forest types often with an understory of bamboo. Thorp and Smith (1949) had some difficulty in deciding whether Ando soils should be placed in the zonal or intrazonal orders, because they did not know whether the dark color of the soils was caused by vegetation or by the soils’ parent material.

The Distinctive Properties of Andosols

Publisher Summary Volcanic ash soils have many unique physical properties that are attributable directly to the properties of the parent material, the noncrystalline materials formed by weathering, and the soil organic matter accumulated during soil formation. These properties include dark soil color, difficult clay dispersion, unique consistence, low bulk density, and high water holding capacity. Soil color is the most striking feature observed for volcanic ash soils, especially for their A horizons. Andisols typically display a large difference in texture when comparing field and laboratory determination methods. Noncrystalline materials play an important role as cementing agents and react with an excess amount of sodium hexametaphosphate. Furthermore, each of the inorganic colloids shows a different point of zero net charge, so that complete dispersion of mineral particles is virtually impossible. Andisols generally have low bulk densities that are attributable to the development of highly porous soil structure. Andisols usually show low degrees of stickiness, plasticity, and hardness that result from the abundance of noncrystalline materials and/or soil organic matter. These physical properties also provide an excellent environment for root growth. Andisols have well-developed soil structure resulting in high porosity with a range of pore sizes that retain a large amount of water with varying tensions.

Chapter 7 Physical Characteristics of Volcanic Ash Soils

Physical and chemical properties and the clay mineralogy of Normal and Light-Colored Andosols from Kitakami, Japan were studied. The profiles of both Andosols had features reflecting the repeated falls of tephras with different ages.The Normal Andosol, which is a common Andosol in Japan, sho

Physical and chemical properties and clay mineralogy of andosols from kitakami, japan

The reaction proceeds with good diastereoselectivity, even when the substrates are applied as mixtures of E/Z-isomers.

Asymmetric Organocatalyzed Epoxidation of 2‐Oxoindoline‐3‐ylidene Acetaldehydes

Asymmetric Nitrocyclopropanation of α-Substituted α,β-Enals Catalyzed by Diphenylprolinol Silyl Ether for the Construction of All-Carbon Quaternary ­Stereogenic Centers

Organocatalyzed Michael, Mannich, and aldol reactions of aldehydes or ketones, as nucleophiles, have triggered several discussions regarding their reaction mechanism. H2 (18) O has been utilized to determine if the reaction proceeds through an enamine or enol mechanism by monitoring the ratio of (18) O incorporated into the final product. In this communication, we describe the risk of H2 (18) O as an evaluation tool for this mechanistic investigation. We have demonstrated that exchange of (16) O/(18) O occurs in the aldehyde or ketone starting material, caused by the presence of H2 (18) O and amine catalysts, before the Michael, Mannich, and aldol reactions proceed. Because the newly generated (18) O starting aldehydes or ketones and (16) O water affect the incorporation ratio of (18) O in the final product, the use of H2 (18) O would not be appropriate to distinguish the mechanism of these organocatalyzed reactions.

16O/18O Exchange of Aldehydes and Ketones caused by H218O in the Mechanistic Investigation of Organocatalyzed Michael, Mannich, and Aldol Reactions

第1報で明らかにされた各種の火山灰土壤について, 母材と土壤生成の関係を研究した結果, 母材の累積的堆積状態が, 各地形面での土壤生成に密接に関係していることが明らかにされた. また本研究では, テフラ中の強磁性鉱物の化学組成が, テフラの識別に有効であることも明らかにされた.研究対象とされた村崎野軽石層までのテフラは, 上部より1,000～5,000年と推定される石英安山岩質の累積火山灰 (金ケ崎および村崎野面の黒ボク土のA1層), 10,000～数万年と推定される安山岩質の累積性火山灰 (例えば村崎野面の黒ボク土のIIBb層), および数万年ないしそれ以上の安山岩質の火山灰と村崎野軽石層 (例えば村崎野面の黒ボク土のIIIAb層以下) よりなっている. そして, このような累積性の母材は, 間けつ的な降灰によって供給されたため, それぞれかって地表風化を受け, 下部ほどよく風化していることが分った.金ケ崎段丘上の火山灰は, すべて若い累積性火山灰 (1,000～5,000年) を母材とする若返りタイプのA1層を形成している. そして火山灰層の下位には扇状地を構成する堆積物が存在する.村崎野段丘では母材の人為的混合, 削剥, 移動再積が各土壤の生成に密接に関係している. この段丘上の黒ボク土のA1層は, 金ケ崎段丘の黒ボク土のA1層の母材に加えて, 下位のIIB1b層の火山灰も一部含まれている. しかもこれらの母材が人為的によく混合されていることが分った. 淡色黒ボク土-IIは, 人為の影響を強く受けて, 黒ボク土のA1層に相当する母材が削剥されて生成している. 一方多湿黒ボク土は, 再積性土壤である.西根段丘の地域の土壤は, 地形の開析が進んでいるため, 頂面 (summit) から背斜面 (backslope) までは削剥土壤である淡色黒ボク土-IIが, また斜面の下部 (footslope) から谷底部 (valley bottom) までは再積性の多湿黒ボク土であることが明らかとなった. なお本地域の火山灰土壤の生成には, 地形と母材に加えて, 人為や植生もまた密接に関係していることが, 考察された.

https://www.jstage.jst.go.jp/article/jaqua1957/17/1/17_1_15/_pdf

Tsuyoshi Ono

Papers

Physical and chemical properties and clay mineralogy of andosols from kitakami, japan

Asymmetric Organocatalyzed Epoxidation of 2‐Oxoindoline‐3‐ylidene Acetaldehydes

Asymmetric Nitrocyclopropanation of α-Substituted α,β-Enals Catalyzed by Diphenylprolinol Silyl Ether for the Construction of All-Carbon Quaternary Stereogenic Centers

16O/18O Exchange of Aldehydes and Ketones caused by H218O in the Mechanistic Investigation of Organocatalyzed Michael, Mannich, and Aldol Reactions

Genesis of Andosols at Kitakami, Iwate Prefecture, Northeast Japan

Tsuyoshi Ono

Papers

Physical and chemical properties and clay mineralogy of andosols from kitakami, japan

Asymmetric Organocatalyzed Epoxidation of 2‐Oxoindoline‐3‐ylidene Acetaldehydes

Asymmetric Nitrocyclopropanation of α-Substituted α,β-Enals Catalyzed by Diphenylprolinol Silyl Ether for the Construction of All-Carbon Quaternary ­Stereogenic Centers

16O/18O Exchange of Aldehydes and Ketones caused by H218O in the Mechanistic Investigation of Organocatalyzed Michael, Mannich, and Aldol Reactions

Genesis of Andosols at Kitakami, Iwate Prefecture, Northeast Japan

Asymmetric Nitrocyclopropanation of α-Substituted α,β-Enals Catalyzed by Diphenylprolinol Silyl Ether for the Construction of All-Carbon Quaternary Stereogenic Centers