The study of lignin with the aim of correlating data, which may lead to a greeter utilization of this wood waste product, has been the subject of investigations since 1838. Previous investigations by Othmer, Harris, Sherrard and others have indicated that chlorinated lignin had potential value as a plastic.
The purpose of this investigation was to study the chlorination reaction of lignin obtained from the black liquors of the sulfate process of paper manufacture. Results of preliminary experimental work indicated that the optimum method of chlorinating lignin was by suspending or dissolving the lignin in methyl alcohol.
The sulfate lignin was chlorinated in two liter wolff flask which was equipped with a motor driven stirrer, and the chlorine flow was measured by a calibrated U-tube differential gage. The flask was charged with the alcohol-lignin mixture and chlorinated from one to seven hours. The rates of chlorine flow for the tests were 0.472, 0.85 and 1.084 gm. Cl₂/min at temperatures of 25 and 65ºC. The reactant gases were passed through a condenser to return the vaporized alcohol to the reaction flask and then into a 3 normal sodium hydroxide solution to react the excess chlorine gas. Samples of the reaction gas, which were analyzed for chlorine, were collected in a 1.5 normal sodium hydroxide solution at 10 minutes intervals. With this information the progress of the reaction could be plotted and the rate of chlorination measured.
The chlorination of a suspension of lignin in methyl alcohol in a ratio of l to 20 was possible at 25°C. The critical temperature above which the lignin would not stay in solution was 43°C. The reaction was exothermic and produced an orange colored product containing 25 per cent chlorine. Increasing the rate of chlorine flow from 0.85 to 1.084gm. Cl₂/min. increased the chlorine consumption from 0.74 to 0.833 gm Cl₂/min.
The chlorination of lignin dissolved in methyl alcohol produced two chlorinated products. One was precipitated as an orange red powder from solution during the chlorination reaction, and had a chlorine percentage as high as 29 per cent. The other lignin remained dissolved in the alcohol solution. When precipitated from solution by ice water this chloro-lignin was a light yellow powder with a chlorine percentage as high as 28.0 per cent. Increasing the rate or chlorine flow trom 0.472 to 1.084 gm Cl₂/min. during tests at 25°C resulted in increasing the rate of chlorination from 0.454 to 0.935gm Cl₂/min. Adding ferric chloride, as a catalyst, increased the chlorine consumption from 0.768 to 0.967 gm Cl₂/min. Raising the reaction temperature from 25 to 65°C decreased the chlorine consumption trom 0.935 to 0.768 gm. Cl₂/min.
The chlorinated product showed definite bonding value when mixed with sawdust and pressed at a temperature or 112°C and pressures from 1000 to 5000 lb/in². The percentage lignin in the samples was varied from 5 to 60 per cent. The lignin-sawdust samples were light yellow in color and firmly bonded and water resistant. / Master of Science
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/76273 |
| Date | January 1946 |
| Creators | Severson, Burns Oscar |
| Contributors | Chemical Engineering |
| Publisher | Virginia Polytechnic Institute |
| Source Sets | Virginia Tech Theses and Dissertation |
| Language | en_US |
| Detected Language | English |
| Type | Thesis, Text |
| Format | [3], 154 leaves, application/pdf, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
| Relation | OCLC# 29449859 |
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