Hydrogenometer (two)

(4) Safety instructions

(1) The catalyst Raney Ni has a high density, sinks to the bottom of the bottle, and the particles are rough.

(2) Long-term use under pressure and heating will cause hydrogenation bottle fatigue and cause danger, so hydrogenation bottles that have been used for 2000h must be resolutely eliminated

(3) The borosilicate glass is not suitable for the reaction of strong alkali medium; the cross meter is a metal product and is not suitable for the reaction of acid medium.

(4) The hydrogenation bottle can only be used for oxidation reactions or carbonyl insertion reactions with a pressure below 60 psi (room temperature) or below 50 psi (heating reaction below 80°C).

(5) The hydrogenation bottle cannot be used for reactions that have exothermic decomposition and polymerization; in addition, for gas production reactions, such as Boc or de-Boc, gas will be generated.

(6) When cleaning, check whether the rubber ring on the PTFE plug is in good condition

(7) When installing the cross meter head, check whether it is actually connected (you can judge by sound and observation, the bottom of the meter head is closed, you can pay attention to it)

(8) There are three valves on the whole device.

(9) When the reaction temperature is too high, especially higher than the boiling point of the solvent used, the temperature should be lowered first when sampling or discharging.

(10) Only after hydrogen gas or carbon monoxide (carbon monoxide (carbonyl insertion) reaction) can start the stirring.

(5) Swing Hydrogenation Apparatus

The swing hydrogenator is also called the swing mixer.

Figure 22-26 Rocking Hydrogenation Apparatus

Because the entire hydrogenation bottle is shaken by shaking, the gas-liquid-solid contact is more frequent and sufficient, which is 3 to 5 times higher than the static stirring efficiency of the hydrogenator, and it has a metal protective cover to prevent hurting people when the bottle bursts

(6) Factors affecting pressure changes

The pressure change in the hydrogenation reaction requires close attention.

(1) A reaction that releases gas during the hydrogenation process

(2) Under hydrogenation conditions, decomposed substances are produced in the reaction system

(3) A large amount of exothermic reaction in the reaction process

(4) In order to promote or inhibit the reaction rate, protect specific groups, etc.
, a certain amount of acid or ammonia gas is added.
When heating, the pressure of the reaction system increases due to vaporization, or even explodes
.
Generally, it is forbidden to strengthen acid and strong alkali in the hydrogenation bottle.
Strong acid corrodes the metal parts above the mouth of the hydrogenation bottle, such as the meter head, male and female inserts, crosses, etc.
, and strong alkali corrodes the hydrogenation bottle
.

(5) A reaction in which low-boiling substances are cooled down at a low temperature and then put into a hydrogenation bottle and then heated
.

Related Links: Hydrogenation Apparatus (1)