Rubber lining sulphuric acid

In spite of the unsaturation of rubber it is said to be resistant to chemical attack since a few chemical derivatives like chlorinated rubbers, cyclised rubbers and chlorides are formed as protective layers retarding further attack by the chemicals. Properly compounded vulcanizates satisfactorily resist the action of most inorganic acids other than oxidizing acids such as nitric, hydrochloric and sulphuric acids. Rubber linings which are to resist swelling to a lower degree should be "tightly" vulcanized. 

Sulphur-dyed cotton fabrics are commonly used for lining boots and other goods made of rubber and, when intended for the purpose, should not be after-treated with copper salts. It is also undesirable to use copper on materials which have been dyed with sulphur blacks because it can cause catalytic oxidation of the sulphur, converting it to sulphuric acid which degrades the cellulose. 

Bjorkmann, of Stockholm, Sweden, gives the following recipe for the nianufacture of the new explosive, vigorite Mix in a wooden or rubber vessel 5 to 20 Mrts of sugar or molasses. 25 to 30 parts of nitric acid, and 50 to 76 parts of sulphuric acid. 25 to SO parts of this mixture, called nltro-line, are mixed with 15 to 86 parts of nitrate of potash and 15 to 35 parts of cellulose. 

The majority of anodizing is performed using process equipment similar to chat found in electroplating. Tanks are typically rubber, plastic or lead-lined steel (which may also serve as the cathode) in the case of sulphuric acid mild steel tanks are preferred for chromic acid. The vigorous oxygen evolution during anodizing creates a fine acid mist which requires effective ventilation and/or... 

To determine the purity of your product, weigh accurately about 0.2 g into a Buchner flask fitted with a rubber bung with a hole to accommodate the tip of a burette containing standardised 0.02 M permanganate. Add 40 cm dilute sulphuric acid, replace the bung, and connect the Buchner to the vacuum line. Warm the flask on a sand bath and titrate with the permanganate solution as before. Repeat the determination and calculate the percentage purity. 

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