A kind of synthetic method of N- ethyl carbazoles
Technical field
The present invention relates to N- ethyl carbazoles, more particularly, to a kind of synthesis of N- ethyl carbazoles green, without discharging of waste liquid
Method.
Background technology
N- ethyl carbazoles are used as the intermediate of the dyestuffs such as green light hydron blue GC and permanent violet RL.Wherein, downstream product it
One permanent violet RL tinting strength, tinting powers are high, bright in luster, even more by excellent chemical properties such as its heat-resisting, sun-proof, resistance to migrations, as
High-end pigment is widely used in coating, rubber, synthetic fibers and plastics industry etc..
The method of commercial synthesis N- ethyl carbazoles is broadly divided into three kinds:Dithyl sulfate method, ethylene ester process and halogen ethane
Method.Dithyl sulfate method obtains N- ethyl carbazoles using dithyl sulfate ethylization carbazole, and dithyl sulfate alkanisation is very capable,
And the moderate alkylation reaction that can be carried out on amino of reaction condition, the hydroxyl without influenceing phenyl ring.Document (Telore
R.D.,Satam M.A.,Sekar N.Dyes and Pigments2015;122:359-367) report, made with acetone molten
Agent, KOH make dithyl sulfate and carbazole reaction, backflow 4h, gained yield is 90% as proton-removed agent.
Using ethyl carbonate as alkylating reagent, European patent EP 0635490 discloses one kind and prepares N- ethylene ester process
The method of ethyl carbazole, using sodium hydroxide, potassium carbonate or potassium ethoxide as proton-removed agent, 24h is reacted, products obtained therefrom purity is
96%.Similar with dithyl sulfate method, the alkylating reagent cost used in this method is high, and reaction needs toxic organic solvents to join
With reaction yield is not high.
By contrast, halogen ethane method is the most extensive in actual applications.Conventional alkylating reagent is mainly chloroethanes and bromine
Ethane, reaction can be divided into homogeneous and heterogeneous synthesis:Homogeneous synthesis is that carbazole first generates carbazole salt, pressurized conditions with proton-removed agent
It is passed through chloroethanes to be ethylized, reaction temperature is higher;Report is more main or using phase transfer catalysis process, i.e., one
In individual multiphase system, being smoothed out for reaction is realized using phase transfer catalyst.Conventional N- alkylations using alkyl quaternary ammonium salts as
Phase transfer catalyst, by the 50%NaOH aqueous solution-benzene mixed solvent as two-phase system.European patent EP 557993 (1993)
The open amine organic matter-triethylamine less expensive using price replaces conventional quaternary ammonium salts as phase transfer catalyst, with 48%
The NaOH aqueous solution-o-dichlorohenzene reacts 9h, reaction yield can reach 99.6% as solvent at 100 DEG C.Likewise, with diethyl
Amine, 2- phenyl -1- propylamine etc. are also fine as catalyst reaction effect.European patent EP 858995 (1998) is with o-dichlorohenzene
Make solvent, N, N, N ', N '-tetramethyl-1,3-propane diamine react 4h, gained yield reaches as phase transfer catalyst at 100 DEG C
99.3%.
Traditional N- ethyl carbazoles synthetic method not only needs toxic organic solvents to participate in alkylation process, has to human body
Evil, environment is polluted, the halogen waste water such as chloride that particularly halogen ethane method is brought, serious environment can be brought by dealing with improperly
Problem.Paid close attention in terms of current Environmental protection, it is particularly intensive to great environmental protection policy appearance in recent years, such as
New environment Protection Code, Air Pollution Prevention Law and ten etc., soil.Therefore, propose a green N- ethyl carbazoles synthesis road
Line, it appears particularly important.
Hydrogenation synthesis N- ethyl carbazoles, it is the effective way realized clean manufacturing and improve product quality, but so far,
Almost nobody synthesizes N- ethyl carbazoles by hydrogenation.Reason essentially consists in the strong electron transfer capacity of carbazole group, makes
The hydro-reduction tool for obtaining vinyl acquires a certain degree of difficulty.Also another key factor, raw material-carbazole 90% is above is derive from coal
Chemical products, because raw material has sulfur containing species in itself, this has also been proposed new requirement for the anti-poisoning ability of catalyst, directly
Connect be related to catalyst apply mechanically activity.
The content of the invention
It is an object of the invention to provide precious metals pd catalyst is applied in the hydrogenation of N- vinyl carbazoles, hydrogen
It is high to change activity, can be with a kind of synthetic method of N- ethyl carbazoles of recycled.
The present invention comprises the following steps:
1) in 1-METHYLPYRROLIDONE solvent, carbazole and proton-removed agent is subjected to salt-forming reaction, generate carbazole salt, is continued
After being passed through acetylene reaction, N- vinyl carbazoles are obtained;
2) in the N- vinyl carbazole organic solvents of generation, Pd catalyst is added, hydrogenation is carried out in auxiliary agent,
Obtain N- ethyl carbazoles.
It is described in 1-METHYLPYRROLIDONE solvent in step 1), by carbazole and the substance withdrawl syndrome of proton-removed agent
Than for 1 ︰ (0.02~0.5), preferably 1 ︰ (0.06~0.12);The temperature of the salt-forming reaction can be 80~100 DEG C, salt-forming reaction
Time can be 20~30min;The condition for continuing to be passed through acetylene reaction can be 140~200 DEG C, anti-under 0.1~0.5MPa
Answer 4~6h.
It is described in the N- vinyl carbazole organic solvents of generation in step 2), by catalyst and N- vinyl carbazoles
Substance withdrawl syndrome ratio can be 1 ︰ (1000~5000);The Pd catalyst may be selected from one kind in phosphate, MgO etc.;It is described
Auxiliary agent can use weak acid, and the weak acid may be selected from one kind in phosphoric acid, hypophosphorous acid etc.;It is described that hydrogenation is carried out in auxiliary agent
Condition can be that pH is 5~7, and 3~4h of hydrogenation is carried out at 0.1~1.2MPa, 30~120 DEG C;The weak acid regulation system
The middle condition for carrying out hydrogenation is preferably that hydrogenation is carried out at 0.2~0.6MPa, 60~100 DEG C.
The present invention is synthesized using two steps:N- vinyl carbazoles are first prepared by carbazole, then direct hydrogenation obtains N- ethyl carbazoles,
Avoid the inferior position that conventional alkylation reagent price is high, toxicity is big, at the same avoid that halogen ethane method brings it is chloride etc. halogen useless
Water emission problem.
The present invention's has the prominent advantages that:
1) a series of preferred special catalyst, the green of N- ethyl carbazoles can be effectively realized by catalytic hydrogenation process
Color synthesizes, and reduces three waste discharge.
2) in hydrogenation process, catalyst is reusable, reduces cost.
3) the N- ethyl carbazole product qualities that hydrogenation technique is prepared are higher.
4) present invention compared with traditional synthesis, it is not necessary to conventional alkylation reagent (dithyl sulfate, ethyl carbonate,
Halogen ethane etc.) and toxic organic solvents participation, no discharging of waste liquid problem, it is a production technology for really meeting green cleaning.
Brief description of the drawings
Fig. 1 is the high-efficient liquid phase chromatogram of the intermediate product N- vinyl carbazoles of the embodiment of the present invention 1.
Fig. 2 is the high-efficient liquid phase chromatogram of the product N- ethyl carbazoles of the embodiment of the present invention 1.
Embodiment
Following examples are for a more detailed description to the present invention, and these embodiments are only to the optimal embodiment party of the present invention
The description of formula, does not have any restrictions to the scope of the present invention.
Embodiment 1
In 50ml glass pressure bottles, 2g carbazoles are added, 0.04g proton-removed agent KOH and 10ml 1-METHYLPYRROLIDONE are made
For solvent, start to stir and be warming up to progress salt-forming reaction 30min at 80 DEG C, generate carbazole sylvite, then pass to acetylene, 160
DEG C, react 2.5h under normal pressure, obtain N- vinyl carbazoles, yield reaches 98.6%;Continue hydrogenation generation N- ethyl clicks in next step
Be 1 ︰ 2000 by catalyst and N- vinyl carbazoles substance withdrawl syndrome ratio during azoles, (carrier is addition Pd catalyst
MgO), it is passed through 0.3MPaH2, hydrogenation is carried out at 70 DEG C, and reaction time 3h obtains N- ethyl carbazoles, and yield reaches
98.8%.
The high-efficient liquid phase chromatogram of the intermediate product N- vinyl carbazoles of the embodiment of the present invention 1 is implemented referring to Fig. 1, the present invention
The high-efficient liquid phase chromatogram of the product N- ethyl carbazoles of example 1 is referring to Fig. 2.
Embodiment 2
In 50ml glass pressure bottles, 2g carbazoles are added, 0.08g proton-removed agent KOH and 10ml 1-METHYLPYRROLIDONE are made
For solvent, start to stir and be warming up to progress salt-forming reaction 20min at 80 DEG C, generate carbazole sylvite, then pass to acetylene, 160
DEG C, react 5h under normal pressure, obtain N- vinyl carbazoles, yield reaches 99.0%;Continue hydrogenation generation N- ethyl carbazoles in next step
During, it is 1 ︰ 2000 by catalyst and N- vinyl carbazoles substance withdrawl syndrome ratio, adds Pd catalyst (carrier MgO),
It is passed through 0.3MPaH2, hydrogenation is carried out at 70 DEG C, and reaction time 3h obtains N- ethyl carbazoles, and yield reaches 98.7%.
Embodiment 3
In 50ml glass pressure bottles, 2g carbazoles are added, 0.12g proton-removed agent KOH and 10ml 1-METHYLPYRROLIDONE are made
For solvent, start to stir and be warming up to progress salt-forming reaction 20min at 80 DEG C, generate carbazole sylvite, then pass to acetylene, 160
DEG C, react 2.5h under normal pressure, obtain N- vinyl carbazoles, yield reaches 98.9%;Continue hydrogenation generation N- ethyl clicks in next step
Be 1 ︰ 2000 by catalyst and N- vinyl carbazoles substance withdrawl syndrome ratio during azoles, (carrier is addition Pd catalyst
MgO), it is passed through 0.3MPaH2, hydrogenation is carried out at 70 DEG C, and reaction time 3h obtains N- ethyl carbazoles, and yield reaches
98.4%.
Embodiment 4
In 50ml glass pressure bottles, 2g carbazoles are added, 0.04g proton-removed agent KOH and 10ml 1-METHYLPYRROLIDONE are made
For solvent, start to stir and be warming up to progress salt-forming reaction 30min at 80 DEG C, generate carbazole sylvite, then pass to acetylene, 160
DEG C, react 2.5h under normal pressure, obtain N- vinyl carbazoles, yield reaches 98.6%;Continue hydrogenation generation N- ethyl clicks in next step
Be 1 ︰ 2000 by catalyst and N- vinyl carbazoles substance withdrawl syndrome ratio during azoles, (carrier is addition Pd catalyst
MgO), it is passed through 0.1MPaH2, hydrogenation is carried out at 50 DEG C, and reaction time 3.5h obtains N- ethyl carbazoles, and yield reaches
98.0%.
Embodiment 5
In 50ml glass pressure bottles, 2g carbazoles are added, 0.04g proton-removed agent KOH and 10ml 1-METHYLPYRROLIDONE are made
For solvent, start to stir and be warming up to progress salt-forming reaction 30min at 80 DEG C, generate carbazole sylvite, then pass to acetylene, 160
DEG C, react 2.5h under normal pressure, obtain N- vinyl carbazoles, yield reaches 98.6%;Continue hydrogenation generation N- ethyl clicks in next step
Be 1 ︰ 2000 by catalyst and N- vinyl carbazoles substance withdrawl syndrome ratio during azoles, add Pd catalyst (carrier for γ-
Al2O3), it is passed through 0.1MPaH2, hydrogenation is carried out at 50 DEG C, and reaction time 3.5h obtains N- ethyl carbazoles, and yield reaches
98.4%.
Embodiment 6
In 50ml glass pressure bottles, 2g carbazoles are added, 0.04g proton-removed agent KOH and 10ml 1-METHYLPYRROLIDONE are made
For solvent, start to stir and be warming up to progress salt-forming reaction 30min at 80 DEG C, generate carbazole sylvite, then pass to acetylene, 160
DEG C, react 2.5h under normal pressure, obtain N- vinyl carbazoles, yield reaches 98.6%;Continue hydrogenation generation N- ethyl clicks in next step
It is 1 ︰ 2000 by catalyst and N- vinyl carbazoles substance withdrawl syndrome ratio during azoles, adding Pd catalyst, (carrier is phosphoric acid
Magnesium), it is passed through 0.3MPa H2, hydrogenation is carried out at 70 DEG C, and reaction time 3h obtains N- ethyl carbazoles, and yield reaches
99.1%.
The invention discloses a kind of green synthesis method of N- ethyl carbazoles.Using carbazole as raw material, carbazole has been added to
In solvent, salt-forming reaction occurs, generates carbazole salt.Continue to be passed through acetylene reaction at ambient pressure, obtain N- vinyl carbazoles.So
Afterwards, noble metal catalyst is added in the organic solvent of N- vinyl carbazoles, catalytic hydrogenation reaction is carried out in a mild condition, obtains
To N- ethyl carbazoles.Present invention, avoiding the inferior position that conventional alkylation reagent price is high, toxicity is big, no discharging of waste liquid, N- ethyls
The yield of carbazole is up to more than 98%.