Sugar from wood

Bergius (2) Also known as Beigius-Willstater-Zechmeister. A process for extracting sugar from wood by hydrolyzing the cellulose with concentrated hydrochloric acid. Lignin remains undissolved. Developed in the 1920s. 

The production of sugar from wood waste has claimed the attention of chemists for the last fifty years. It is of interest, both as a process of producing a supplement to agricultural products and also as a means of converting the vast amount of wood waste resulting from lumber manufacture into useful products. 

Processes for the production of sugar from wood are grouped in two classes (1) the hydrolysis of wood at elevated temperature and pressure with dilute acid (sulfuric or hydrochloric) as a catalyst and (2) the treatment of wood with strong acid in which it is dissolved and then dilution with water and hydrolysis of the resulting solution. 

Udic-Rheinau A process for making sugars from wood by hydrolysis with hydrochloric acid. Operated in Germany. See also Bergius (2). 

Bergius-Willstatter saccharification process. Process for industrial production of fermentable sugar from wood by hydrolysis of tannin and xylan-free cellulose with 40-45% hydrochloric acid. The use of concentrated acid requires acid-resistant equipment and recovery of acid. The sugar produced must be rehydrolyzed prior to fermentation. 

In this period Fischer began to be involved with the substitute foods commission, and other commissions such as the one for fat and oils. One of the most important projects was the production of food by heating straw with caustic soda. In May 1916 about 100,000 tons of straw were used for this process. By-products were methanole and acetone, and Fischer offered them to the Bayer company. He knew, however, that the production of acetone from acetylene was already under way. Fischer also tried to find a substitute for coffee. He offered to use synthetic caffeine and mix it with sliced turnips. He made different trials and offered the result to Bayer. In 1918 he reported to the Bayer company on the production of sugar from wood. Richard Willstatter had tried to develop this process, which the Holzspiritusfabrik in Mannheim scaled up for production. But Fischer was not convinced of the efficiency of this company and, in fact, it did not run well. In the 1920s the Nobel Prize winner Friedrich Bergius improved this process and built up a new factory which remained in operation until after World War II. 

Cellulose an unbranched plant polysaccharide, M, 300,000-500,000, consisting of pi,4-linked glucose units. C. is enzymatically hydrolysed to the disaccharide cellobiose. It can be hydrolysed to D-glucose by treatment with concentrated acids, such as 40% HCl or 60-70 % H2SO4 at high temperature. This process, called saccharification of wood, is used to produce fermentable sugar from wood. 

HemiceUulose is a mixture of amorphous branched-chain polysaccharides consisting of a few hundred sugar residues. They are easily hydrolyzed to monomeric sugars and uronic and acetic acids. Many different hemiceUuloses have been isolated from wood. 

Although the hydrolysis of wood to produce simple sugars has not proved to be economically feasible, by-product sugars from sulfite pulping are used to produce ethanol and to feed yeast (107). Furthermore, a hemiceUulose molasses, obtained as a by-product in hardboard manufacture, can be used in catde feeds instead of blackstrap molasses (108). Furfural can be produced from a variety of wood processing byproducts, such as spent sulfite Hquor, bquors from the prehydrolysis of wood for kraft pulping, hardboard plants, and hardwood wastes (109). 

Sony Energytec uses a disordered hard carbon of the type described in region 3 of Fig. 2. These carbons have been produced by a number of Japanese manufacturers including Kureha [41] and Mitsubishi Gas [40], Our recent work [44], and other work in the patent literature shows how such carbons can be produced from natural precursors like sugar and wood. This suggests that it should ultimately be possible to prepare such carbons very cheaply. The specific capacity of region-3 carbons which are in commercial production are around 500 mAh/g. 

Tannins are polyhydroxyphenols. They are soluble in water, aleohols and aeetone and ean eoagulate proteins. They are yielded by extraetion from wood substanee, bark, leaves and fruits. Other components of the extraction solutions are sugars, pectins and other polymeric carbohydrates, amino acids and other substances. The content of non-tannins can reduce wood failure and water resistance of glued bonds. The polymeric carbohydrates especially increase the viscosity of the extracts. 

Biomass includes chemicals obtained from wood, sugar, grain, etc. A totally renewable source, it will become more important in the future. 

Before 1900, a large share of the chemical industry was based on biomass it served as a feedstock for chemicals made from wood, sugars, starches, and fats. 

The situation with regard to ethanol is much clearer there is long industrial experience in the manufacture of ethanol from wood, by fermentation of the sugars in the waste effluents of pulp mills, or of the sugars made by wood hydrolysis ( ). In the years following World War II, wood hydrolysis plants have been unable to compete economically with petroleum-based ethanol synthesis, mainly by hydration of ethylene, and they have been shut down in most countries. However, in the Soviet Union, we understand, there are still about 30 wood hydrolysis plants in operation (10). Many of these are used for fodder yeast production (11) but the wood sugars are also available for ethanol production. 

While ethanol from wood sugars has not been part of that program, the successful substitution of ethanol for gasoline commercially has raised the prospect of a large market outlet, and the rapidly increasing price of gasoline here suggests that the economics, if not favorable now, may become so in a foreseeable future. 

Alcohol recovery from the fermentation brews was less than complete in most cases, which may be attributable to less than ideal conditions. The best yields, 60 to 97% of theory, were obtained with sugars obtained by hydrolysis of cellulosic residues of the autohydrolysis-extraction process. Unextracted pulps, or the hemicellulose solutions, gave poor ethanol formation, which suggests inhibition. In the calculation of material and energy balances which follows, we have assumed 95% yields of ethanol from wood sugars, which is readily achieved in industrial practice and which we believe to be achievable with our wood sugars as well. 

Mention has already been made of two polymers that can be obtained naturally from living animals silk (from the silkworm) and wool (from sheep). They are proteins made of various amino acids both are used in textiles. Other biologically derived polymers are also familiar such as wood, starch, and some sugars. We will not cover these in detail here. However, certain cellulosics we will discuss briefly since they are compared to synthetic fibers later. Cellulose is the primary substance of which the walls of vegetable cells are constructed and is largely composed of glucose residues. It may be obtained from wood or derived in very high purity from cotton fibers, which are about 92% pure cellulose. 

Production of 2,3-Butylene Glycol from Wood Sugar. 184... 

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