Green carbon feedstock

In the process, the carbon feedstock is calcined (1250°C) to volatilize any impurities, after which the calcined products are ground, screened, weighed, mixed with binder, formed by molding or extrusion into green electrodes, and arranged in the furnace (Fig. 4). 

Filler coke is formed by the same general mechanism as that already described for binder coke. However, the feedstocks used are various petroleum residual fractions, instead of coal tar. Temperatures of 400-500°C convert these resids into green coke within a day. A complex series of endothermic pyrolysis reactions produce liquid-crystal mesophase which is transformed to a carbon polymer of generally graphitic structure. However, there are varying amounts of... 

In some cases, green reactions are based on feedstocks derived from renewable resources that produce highly pure compounds. Another green option is the use of supercritical fluids that are more benign substances (e.g., water, carbon dioxide, and light nonhalogenated hydrocarbons) such fluids can be used as solvents for separations or as media for reactions, and can be easily recovered from the product mixture and recycled. We can also include here the use of ionic systems of nonvolatile salts that are molten at ambient temperature, and that act as solvents or even have a dual role (as catalysts and solvents), without the risk of unwanted vapors. These ionic solvents replace the more hazardous, volatile, and expensive organic solvents used traditionally. 

Using carbon dioxide as a feedstock in synthetic chemistry is an important area of green chemistry. It is significantly soluble in water, and water is therefore a good medium for its conversion. However, when it dissolves it forms carbonic acid (Figure 3.13). Considerable efforts have been made to understand this process and control the pH of aqueous-carbon dioxide systems.This is also highly relevant to studies involving supercritical carbon dioxide and water in biphasic catalysis, especially for pH-sensitive enzymes. 

Coke consists mainly of carbon (90-95%) and has a low mineral matter content (determined as ash residue). Coke is used as a feedstock in coke ovens for the steel industry, for heating purposes, for electrode manufacture, and for production of chemicals. The two most important categories are green coke and calcinated coke. This latter category also includes catalyst coke deposited on the catalyst during refining processes this coke is not recoverable and is usually burned as refinery fuel. 

Succinic acid, known as amber acid or butanedioic acid, is a four-carbon dicarboxylic acid produced as an intermediate of the tricarboxylic acid cycle (TCA) [1,2]. Succinic acid and its derivative have wide industrial applications such as the feedstock of food and pharmaceutical products, as the intermediate of chemical synthesis of surfactants, detergents, green solvents, and biodegradable plastics, and also as ingredients of animal feeds to stimulate animal and... 

Another ideal aspiration of the proponents of green chemistry is that the feedstock should be renewable. Renewability can take a variety of forms, but all avoid the gouging out of resources from the Earth. Nature furnishes crops each year, and they count as renewable due to the benevolence of the Sun and its powering of the recycling of carbon dioxide through the medium of photosynthesis. Materials other than carbon dioxide can be recycled and plans have been proposed for the treatment of landfill as mines, but that resource is hazardous and not open to geological judgement. 

The first part of this chapter is intended to survey recent literature on new catalytic materials because the development of new types of metal oxides and layered- and carbon-based materials with different morphologies opens up novel acid-base catalysis that enables new type of clean reaction technologies. Mechanistic considerations of acid- and base-catalyzed reactions should result in new clean catalytic processes for Green and Sustainable Chemistry, for example, transformations of biorenewable feedstock into value-added chemicals and fuels [21-35]. The latter part of this chapter, therefore, focuses on biomass conversion using solid acid and base catalysts, which covers recent developments on acid-base, one-pot reaction systems for carbon-carbon bond formations, and biomass conversion including synthesis of furfurals from sugars, biodiesel production, and glycerol utilization. 

As shown in Fig. 10.4, the origin of the feedstock defines the color as well as the carbon footprint of the hydrogen. Available renewable feedstocks are green electricity as well as renewable biomass— be it gaseous, solid or liquid. 

To start with, the most abundant five- and six-carbon sugars and some of their isomers, as well as shorter chained sugars, are indicated in green. Chemicals produced by fermentative or biocatalytic processes of carbohydrate feedstocks are... 

Fig. 8 0 C vs F C ratio for a range of carbohydrate-derived chcanicals and derivatives thereof. Feedstocks highlighted in green box. Cx resp. x-carbon monosaccharide...

Fig. 9 F C ratio for a selection of carbohydrates, carbohydrate derivatives, and other chemicals, ordered by carbon number. Feedstocks highlighted in green. Blue arcs, see text...

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