SU1610314A1 - Method of calortmetric titration - Google Patents

Abstract

The invention relates to calorimetry, in particular, to methods for measuring the thermal effects of interaction in liquid-liquid systems on calorimeters having an isothermal shell. The purpose of the invention is to increase the resolution and accuracy of calorimetric titration. A temperature-controlled titrant in an isothermal shell is continuously pumped through a heat exchanger installed in a calorimetric vessel and a switch valve, which allows for the introduction of a dose of titrant at a temperature of a calorimetric vessel with an idle input effect close to zero. The amount of dose administered is controlled by the gravimetric method. 1 il.

Description

This invention relates to calorimet-. rii and can be used for dl. measuring heat effects of interaction in liquid-liquid systems on calorimeters having an isothermal shell.

The purpose of the invention is to increase the resolution and accuracy of calorimetric titration by decreasing the idle thermal effect of introducing a titrant into a calorimetric vessel and controlling the dose of titrant by the gravimetric method ..

The drawing shows a device for carrying out the proposed method.

The device consists of a heat exchanger 1, placed in an isothermal shell of the calorimeter, and a calorimetric vessel 2, fixed in a calorimetric socket 3. The calorimetric vessel 2 is closed with a conical lid 4, on which heat exchanger 5, valve switch 6, electric heater 7, inlet fitting 8 for are located titrant, outlet nozzle 9 for the titrant and nozzle 10 for the injection solution. The valve switch 6 allows directing the flow of titrant into the outlet fitting 9 or into the volume of the calorimetric vessel 2 through the windows 11. The valve is controlled using button 12. At the exit of the titrant from the calorimeter, a faucet .13 is installed to select portions of the titrant.

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The method is carried out as follows.

The calorimeter is brought to the desired mode with a working micropump. Using a micropump, Tit Wrant is continuously pumped through the heat exchanger 1 in an isothermal shell, where it receives its temperature and then enters the heat exchanger 5, where it receives the temperature of the vessel, then returns through valve switch 6 and the fitting 9 to the external tank with a titrant. therefore, the temperature of the titrant in the switch-valve 6 is always equal to the temperature of the calorimetric vessel .. Therefore, if using the switch-valve 6 to direct the flow of the titrant into the volume of the calorimetric vessel 2, then the idle heat oic effect titrant input will be close to zero. The heat flux introduced by the titrant flux from the isothermal shell acquires the character of constant heat release over the entire calorimetric experiment, which allows it not to be taken into account when processing the results of the experiment. The PPM-type scrubber pump pumps the titrant in small portions, the change in the magnitude and speed of which is provided by the pump design. The use of a 2C grade pumping unit with a precision ruby plunger allows to obtain highly reproducible in mass portions of the pumped titrant. A tap 13 installed at the outlet of the calorimeter allows the selection of a known number of portions, which are then weighed and the mass of a single portion is calculated from their mass. Determination of the mass of a single portion can be carried out at any time, except for the moment the titrant is introduced into the calorimetric vessel through the valve-switch 6.

Weight control of the titrant dose is carried out as follows. The titrant is pumped with a micropump one: IN ANIMAL portions with a constant speed

rosty. Through the valve 13, the titrant stream is transferred to the weighed container and the known number of portions of the titrant is collected. By weighing the container before and after sampling, the total mass of a single portion is determined by the formula

ha: -

M

 I

P

0

Q 5

0

five

0

50

five

where t is the mass of a single portion;

M is the total mass of the selected titrant;

n is the number of selected portions. If you know the mass of a single portion, you can calculate the mass of the dose of titrant introduced into the calorimetric vessel through the valve-switch 6:

D m- k,

where D is the mass dose of the titrant;

k is the number of portions of the titrant, introduced into the calorimetric vessel.

At the highest point of the internal volume of the calorimetric vessel 2 there is an opening for draining the impurity solution through the nozzle 10, which excludes the presence of free vapor space in the vessel. The dose is determined by the number of portions of the titrant introduced through the valve-switch 6 into the calorimetric vessel 2. The dose of the titrant is not limited.

For example, when a prototype is introduced into a calorimetric vessel with a volume of 100 cm, a portion of water with a volume of 10 cm with a temperature difference between the calorimetric vessel and the isothermal shell equal to 0.2 K, the idle effect will be approximately 10 J. The proposed method gives an idle an effect of 0.1 J, which increases the resolution of measuring thermal effects by a factor of 100.

Claims (1)

The formula of the invention H And Calorimetric titration method, which includes temperature control of the titrant in the isothermal shell of the calorimeter, characterized in that, in order to increase the resolution and titration accuracy by reducing the idle thermal effect from introducing the titrant to the calorimetric vessel, the titrant is continuously pumped through the closed loop through the calorimetric vessel, carried out the dose of titrant, the amount of which is controlled by weighing. FREE CONTROL DOSES