Sciencemadness Discussion Board

Sugar(fermentable goods) from cellulose?

testimento - 9-7-2013 at 20:25

I heard that it is possible to make short chained carbohydrates from wood by boiling them long enough. Another method was to use sulfuric acid to ferment food: Some 100-150kg was needed to produce over one ton of sugar-like substance.

Metacelsus - 10-7-2013 at 08:23

Quote: Originally posted by testimento  
Some 100-150kg was needed to produce over one ton of sugar-like substance.


This is a blatant violation of conservation of mass. Where did you find this information?

Magpie - 10-7-2013 at 09:37

I think he means the amount of acid required.

FYI - an edited extract from: http://www.sandyhershelman.com/alcoholplanthistory.htm

From 1911 to 1913, the Classen Chemical Company made alcohol out of sawdust at a plant built at the southern tip of Port Townsend Bay, WA.

Classen made its alcohol using a French distilling process known as the Bergius Process.

Wood waste, shredded into chips, was dried in a steam dryer until it contained no more than one percent moisture. The wood was mixed with cold 40 percent hydrochloric acid. The cellulose was converted to glucose, and the lignin extracted.

Through evaporation, the acid was also recovered and reused. Fresh supplies of the acid were made in stone tanks from salt and sulfuric acid.

Special yeast, grown in the plant, was added to the fermentation tank housing the glucose-rich wood solution.

When the "beer" was ready, the eight-percent-alcohol solution was moved from the beer well and entered the distillation stage. This distillation yielded 190-proof ethyl alcohol. The neighboring cattle also benefited: the spent wort was used for feed.

Metacelsus - 10-7-2013 at 10:31

Oops, sorry for the confusion. I thought you meant 100-150 kg of cellulose. Yes, I have heard of acid-catalyzed hydrolysis of cellulose:

http://www.eng.umd.edu/~nsw/ench485/lab4.htm

https://en.wikipedia.org/wiki/Acid_hydrolysis

http://www.google.com/patents/US4174976

The hydrolysis is usually done with dilute sulfuric acid.

Fantasma4500 - 12-7-2013 at 07:13

interesting, been wondering for some time where the cellulose went then conc. H2SO4 was added to it, by logic it wouldnt just disappear without any type of decomposition etc.
first carbonised, thereafter nowhere to be found
since dilute acids are used, i wonder if concentrated acids could yield a different compound, speed up the reaction overall or totally ruin it?

Adas - 12-7-2013 at 07:27

Quote: Originally posted by Antiswat  
interesting, been wondering for some time where the cellulose went then conc. H2SO4 was added to it, by logic it wouldnt just disappear without any type of decomposition etc.
first carbonised, thereafter nowhere to be found
since dilute acids are used, i wonder if concentrated acids could yield a different compound, speed up the reaction overall or totally ruin it?


Concentrated acids would just carbonize it.

hyfalcon - 12-7-2013 at 08:28

Isn't 40% HCl above the concentration of the azotrope?

Random - 29-8-2013 at 16:13

i want pure lignin, in which form is it present after wood hydrolysis?

Would 18 percent HCl be sufficient?

Agricola - 2-11-2013 at 14:28

Attached to this post is a paper on the preparation of alcohol from grass. The cellulose of grass is converted by the enzyme cellulase to glucose which is then fermented to alcohol.

You can read about cellulase here.

Attachment: alcohol_epstein2010.pdf (600kB)
This file has been downloaded 741 times

Ozone - 2-11-2013 at 15:31

Dilute acid will not work with whole biomass or crystalline cellulose. Strong acid such as quenched sulfuric (72%) or supersaturated HCl are required (they dissolve HCl gas into cold 36-38% acid to 40-42% and keep it cold under pressure in a reactor). The acid is extracted or otherwise removed for recycling. Once the primary hydrolysis is complete, the liquor is strained from the lignin (which is washed to remove residual acid) and the mixture of glucose and higher DPs is subject to a secondary hydrolysis, usually with dilution and high heat, say 120°C. The result is a mixture of sugars with DP 1 >90 %.

This mixture us then refined and evaporated to give a fermentable product.

Although not required for strong acid hydrolysis, pretreatment can be done to remove the hemicellulosic sugars prior to hydrolysis. This is usually done with dilute acid at high temperature under pressure. The hemicellulose depolymerizes, but the cellulose does not.

Personally, I'd pretreat it with NaOH, wash it well, and saccharify it with a cellobiase-cellulase cocktail.

But that's just me.

Cheers,

O3

[Edited on 2-11-2013 by Ozone]