The electrical resistance to currents of high frequency shown by wires that are enclosed in conducting envelopes
✍ Scribed by G.F.S.
- Publisher
- Elsevier Science
- Year
- 1923
- Tongue
- English
- Weight
- 115 KB
- Volume
- 196
- Category
- Article
- ISSN
- 0016-0032
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✦ Synopsis
LABORATORY experiments were made to determine the effect of using small quantities of catalysts. With hydrochloric, sulphuric, and phosphoric acids a marked increase in the yield of furfural was obtained when the quantities of acid added were sufficient to neutralize the natural base of the cobs. Larger quantities did not give a proportionate increase. The effect of the mineral acids is probably due largely to the organic acids, especially formic, which are liberated. Direct addition of formic acid produced a somewhat greater increase in yield than did the mineral acids. Sulphurous acid gave results comparable with those obtained by formic acid, indicating that the presence of a reducing agent increases the yield. From an economic standpoint the sulphuric and sulplmrous acid catalysts seem to offer the greatest promise.
Semi-commercial runs using the sulphuric acid catalyst gave furfural yields of about 9 per cent., 5 ° per cent. higher than those obtained in steam digestion without catalysts. The small quantity of acid used does not require neutralization, and there is 11o increase in steam requirement for the process. Hence the catalytic process offers a decided commercial advantage.