| 单词 | pyrogallol |
| 例句 | The one called the pyrogallol group, which includes sumac, gall nuts and oak bark, is commended by the Committee of the Society of Arts. Library Bookbinding 2011-12-24T03:07:58.950Z An alkaline solution of pyrogallol is also used; this solution rapidly absorbs oxygen, becoming black in colour, and it is necessary to prepare the solution immediately before use. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 4 "G" to "Gaskell, Elizabeth" 2011-08-24T02:00:20.690Z The pyrogallol method of Preisz also proved to be unreliable in his hands. Contagious Abortion of Cows 2011-02-14T03:00:33.157Z The tannins are divided into two general classes, known respectively as the pyrogallol tannins and the catechol tannins. The Chemistry of Plant Life The acid is a phenolic derivative of benzoic acid, viz. trihydroxybenzoic acid, and on heating it readily passes into trihydroxybenzene, which is the “pyrogallic acid” or pyrogallol familiar as a photographic developer. Coal and What We Get from It The United States Government Printing Office proposals call for leathers tanned with a pyrogallol tannin, since it has been proved that such leathers prove most resistant to the evil effects of light, heat and gas. Library Bookbinding 2011-12-24T03:07:58.950Z The class of tanning materials which produce the most suitable leather for this particular purpose belong to the pyrogallol group, of which a well known and important example is sumach. Bookbinding, and the Care of Books A handbook for Amateurs, Bookbinders & Librarians In collodion it should at first not be used of greater strength than three to four per cent., as in this form pyrogallol sometimes acts with unexpected energy. Essentials of Diseases of the Skin Including the Syphilodermata Arranged in the Form of Questions and Answers Prepared Especially for Students of Medicine It exhibits all the characteristic properties which have been listed above for tannins in general and responds to all the characteristic reactions of a pyrogallol tannin. The Chemistry of Plant Life The phthaleïn formed from gallic acid and phthalic anhydride really results from the union of the latter with pyrogallol. Coal and What We Get from It In the American and Japanese species they are a mixture of catechol and pyrogallol tannins, while they appear to be pure pyrogallol tannins in the Chinese species. Northern Nut Growers Association Report of the Proceedings at the 43rd Annual Meeting Rockport, Indiana, August 25, 26 and 27, 1952 A brown sepia is obtained by toning first with potassium permanganate, 1 per cent. of water, then, after washing, with a solution of pyrogallol. Photographic Reproduction Processes Newton employs it in combination with pyrogallol and soda in the development of bromo-gelatine plates. Scientific American Supplement, No. 483, April 4, 1885 Dr. Eder has for a considerable time directed especial attention to the soda and potash developers, either of which seems to offer certain advantages over the ammoniacal pyrogallol. Scientific American Supplement, No. 415, December 15, 1883 But although pyrogallol is a benzene derivative, and could if necessary be prepared synthetically, it can hardly be claimed as a tar product, as it is generally made from gallic acid. Coal and What We Get from It If gallic acid be used instead of pyrogallol, the tone is black. Photographic Reproduction Processes |
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