如何凯发国际网址溶液中的纤维素?

 来源:http://www.hbctest.com/news/17.html     时间:2019-07-17
溶液中纤维素的凯发国际网址步骤如下:

The detection steps of cellulose in solution are as follows:

(1) 配制所需的各种溶液,硫酸亚铁铵溶液在使用的一周内准备,并在使用当天测定其滴定度K。用该硫酸亚铁铵溶液滴定25mL 0.1N的重铬酸钾溶液,用去m mL。K= 25×0.1/m

(1) All kinds of solutions needed for preparation, ammonium ferrous sulfate solution is prepared within a week of use, and its titration K is determined on the day of use. The ammonium ferrous sulfate solution was used to titrate 25 mL 0.1N potassium dichromate solution, and m mL was removed. K = 25 x 0.1/m

(2) 称取自然风干的生物质粉末0.05-0.06g,数值为n。

(2) The natural air-dried biomass powder was weighed 0.05-0.06g and the value was n.

(3) 装入离心管内,加入硝酸和醋酸的混合液5mL。

(3) Put it into centrifugal tube and add 5 ml mixture of nitric acid and acetic acid.

(4) 塞住离心管,在沸水中煮沸25min,并定期搅拌。

(4) Close the centrifugal tube, boil it in boiling water for 25 minutes, and stir regularly.

(5) 离心,倒去清液,加入蒸馏水离心洗涤沉淀,共洗三次 。

(5) Centrifuge, pour out the clear liquid, add distilled water to centrifuge, wash and precipitate three times.

(6) 加入10mL 0.5N的重铬酸钾溶液和8mL浓硫酸,搅匀,放入开水中10min,并定期搅拌 。

(6) Add 10 mL 0.5N potassium dichromate solution and 8 mL concentrated sulfuric acid, stir well, put in boiling water for 10 minutes, and stir regularly.

(7) 冷却,倒入锥形瓶中,用少许蒸馏水冲洗沉淀,滴入3滴试亚铁灵试剂,用0.1N的硫酸亚铁铵溶液滴定,用去b mL,由黄色经黄绿色至红褐色为终点。

(7) Cooling, pouring into a conical bottle, rinsing and precipitating with a little distilled water, dropping 3 drops of ferrous reagent, titrating with 0.1N ammonium ferrous sulfate solution, using removal of B mL, from yellow to red-brown as the end point.

(8) 用0.1N的硫酸亚铁铵溶液单独滴定加入8mL浓硫酸和10mL 0.5N重铬酸钾溶液,用去a mL 。

(8) Add 8 mL concentrated sulfuric acid and 10 mL 0.5N potassium dichromate to titrate with 0.1N ammonium ferrous sulfate solution separately and remove a mL.

(9) 生物质中纤维素的含量计算公式: x% = 0.675×K(a-b)/n 0.05mol/L硫代硫酸钠溶液。

(9) Formula for calculating cellulose content in biomass: x% = 0.675 *K(a-b)/n 0.05mol/L sodium thiosulfate solution.



实验原理如下:

The experimental principle is as follows:

生物制粉末在加热的情况下用醋酸和硝酸的混合液处理,在这种情况下,细胞间的物质被溶解,纤维素也分解成单个的纤维,木质素、半纤维素和其它的物质也被除去。淀粉、多缩戊糖和其它物质受到了水解。用水洗涤除去杂质以后,纤维素在硫酸存在下被重铬酸钾氧化成二氧化碳和水。 C6H10O5 + 4K2Cr2O7 + 16H2SO4 = 6CO2 + 4Cr2(SO4)3 + 4K2SO4 + 21H2O

Biological powders are treated with a mixture of acetic acid and nitric acid when heated. In this case, substances between cells are dissolved, cellulose is decomposed into individual fibers, and lignin, hemicellulose and other substances are removed. Starch, pentose polycondensate and other substances were hydrolyzed. After removing impurities by washing with water, cellulose is oxidized to carbon dioxide and water by potassium dichromate in the presence of sulfuric acid. C6H10O5 + 4K2Cr2O7 + 16H2SO4 = 6CO2 + 4Cr2 (SO4) 3 + 4K2SO4 + 21H2O

过剩的重铬酸钾用硫酸亚铁铵溶液滴定,再用硫酸亚铁铵滴定同量的但是未与纤维素 反应的重铬酸钾,根据差值可以求得纤维素的含量。

The excess potassium dichromate is titrated with ammonium ferrous sulfate solution, and then with ammonium ferrous sulfate to titrate the same amount of potassium dichromate without reaction with cellulose. The content of cellulose can be calculated according to the difference.

相关新闻

相关产品