SU905189A1 - Method for detecting carbon and hydrogen in organoselenium compounds - Google Patents

Description

t

This invention relates to analytical chemistry, specifically to a method for determining the elemental composition of organic substances.

A known method for determining carbon and hydrogen in organo selenium compounds, which turns off the capture of selenium oxide in a Pregl quartz apparatus, which is filled with crushed quartz, cooled with water and ground to a combustion tube C

There is also known a method for determining carbon and hydrogen in organo selenium compounds by quantitative condensation of c-eleven dioxide in the cold zone of a tube in a sleeve filled with quartz cotton 2.

The disadvantage of these methods is the low absorption of selenium oxide by quartz.

The closest to the proposed method is the determination of carbon and hydrogen in organic selenium

compounds, which include the absorption of salga in the first stage by the Kakabadze catalyst, which is a mixture of copper oxide and magnesium oxide.

. A portion of the analyte 5 in a cup is filled with 300 ml of Kakabadze catalyst, previously calcined to constant weight in a stream of oxygen at 850 ° C, and introduced into a quartz tube with a sleeve

10 filled with the same catalyst. The decomposition of the sample takes place at BSO-SOO C at an oxygen rate of M25 ml / min, the sleeve with the catalyst is heated to lOO. Selenium oxide

15 is partially absorbed in the cup, quantitatively in the sleeve, and hydrogen is determined by the usual method 31.

The disadvantage of this method is that in addition to carbon and

20 hydrogen, other elements cannot be determined, since the catalyst absorbs not only selenium oxide, but also phosphorus oxide. The purpose of the invention is to develop a method for the simultaneous determination of carbon, hydrogen and phosphorus in organo selenium compounds. This goal is achieved by burning the analyte and absorbing selenium oxide in the first stage with nickel oxide at 280300 ° C, and carbon, hydrogen and forfor are determined by known methods. The catalyst is prepared as follows. Nickel oxide (N10) is kneaded with distilled water to a thick slurry. The resulting mass is rubbed through a sieve, the formed nickel oxide granules are calcined in chamotte crucibles in a muffle at 1000 for 2 hours, and then in an atmosphere of a quartz tube in an atmosphere of air at 1100-1150 for 10 hours. Example 1. mg is placed in a quartz glass and fall asleep by 2/3 quartz. The cup is then introduced into a combustion tube with a sleeve filled with nickel oxide heated to 280 ° C. The decomposition of the sample was carried out at a rate of 25 ml / at oxygen. Burn duration 0 min. Found,%: C, 51.83; 52.12; H 5.85, 5.69; Р 10.03, 10.37С «ЧРа-5е Calculated: С B2, ПП, Н 5, б7, Р 10.34. The error in determining the carbon of hydrogen and phosphorus is ± 0.3 abs. % Example 2. A weighed portion of 5 mg of Cjj gPOSe is placed in a quartz glass and covered with 2/3 of quartz. At the same time, it is introduced into a quartz tube, with a helium filled with nickel oxide, heated to. The decomposition of the sample is carried out gradually at a rate of 25 ml / min of oxygen. Duration 0 min. Found,%: C 51.96; 51.71; H 6.31, 6.32; Р 10.00, 10. ОДДРОЗе С 51.82; H 6.31, Calculated, R 10.29. The error in determining carbon, hydrogen and phosphorus is +0.3 abs. % 94 - Diphenydidelenide () is taken as a standard substance when burning organo-organic compounds. All burn options are carried out on this standard. The temperature of the sleeve with nickel oxide 260-270C. A portion of -wSej 3.63 mg is burned as indicated in Example 1. Found,%: C 5.1, H 2-39- “Calculated,%: C 46.20, H 3.21. The temperature of the liner with nickel oxide is 280-30 ° C. A portion of diphenyl selenide, 3.45 mg, is burned as in example 1. Found: C 46.10, H 3.01. Calculated,% C 46.20, H 3.21. The temperature of the sleeve with nickel oxide is 310-320 0. 4.77 mg of diphenyl selenide is analyzed according to Example 1. Found: C 48.34, H 4.90. Calculated; %: C 46.20 ,, H 3.21. As can be seen from the above data, the most optimal is burning at the temperature of the liner with oxide jet 280-300 ° C. At temperatures below the liner, carbon and water results are underestimated due to the partial adsorption of carbon dioxide and water on nickel oxide, and with increasing temperature above. overestimate results due to the volatility of selenium dioxide. The results of analyzes of the standard substance and phosphorus-containing seleno-organic compounds are given in the table. The proposed method makes it possible to simultaneously determine carbon, hydrogen, and phosphorus in organo selenium compounds. Errors of determination do not exceed ± 0.3 abs. %, The method is simple to implement, it does not require special instrumental formation. The catalyst used to absorb selenium oxide is available and can be easily prepared by any analytical laboratory. The analyzer can be used without regeneration for 45-50 determinations of the elemental composition of selenium-organic compounds.

Claims (1)

Claim A method for determining carbon and hydrogen in organo-selenium compounds, including burning a sample in an oxygen stream at 850 ~ 900 ° С, absorbing the formed selenium oxide on a catalyst, followed by analysis by one of the known methods, characterized in that, in order to simultaneously determine carbon, hydrogen and phosphorus, nickel oxide is used as an absorber of selenium oxide at 280 ~ 300 ° C.