A kind of method for preparing dichlorohydrine from glycerine
Technical field
The invention belongs to chemical field, is about the propylene oxide intermediates preparation.A kind of method for preparing dichlorohydrine from glycerine of more specifically saying so.
Background technology
Dichlorohydrine is the key intermediate in the epoxy chloropropane production process, and its annual production is near 2,000,000 tons.The main method of producing dichlorohydrine in the world wide is based on the propylene high-temperature chlorination process of U.S. shell company in exploitation in 1948, and preparation process comprises:
Such technology has technical maturity, and raw material propylene source is sufficient, can satisfy great demand, but also there is important disadvantages in this operational path: 1. high-temp chlorination, and energy consumption height, side reaction are many; 2. the easy green coke of reaction process, equipment needs the frequent shutdowns coke cleaning; 3. the utilization ratio of chlorine has only about 38% in the reaction process, and the concentration of product dichlorohydrine generally is controlled at 4%, so produces very a large amount of chlorine-contained wastewaters in the production process.Yet all use such method to produce dichlorohydrine at present in about 90% the epoxy chloropropane full scale plant.
The method of the suitability for industrialized production dichlorohydrine of another less use is the propylene acetate method, and reaction process comprises:
Compare with traditional propylene high-temperature chlorination process, above-mentioned propylene acetate method has stable operation, and the chlorine consumption is few, the advantage that side reaction is less relatively.But this operational path is long, and investment is big, and the palladium catalyst life-span is short, the production cost height.
Generally speaking above-mentioned two commercial runs are the non-renewable petroleum resources of mass consumption all, but also mass consumption chlorine causes serious environmental to pollute.
So, in the last few years, worldwide just to seek new method and producing dichlorohydrine, the glycerine method that derives from renewable resources comes into one's own.The primitive reaction principle of this method is:
The method of No. 197308,1906, German Patent research is to be catalyzer with acetic acid or propionic acid, at 100 ℃ of left and right sides HCl gases and glycerine reaction 20~40h, obtains yield and be 75% dichlorohydrine.The carrying out of the water inhibited reaction that generates.
United States Patent (USP) 2144612 adds n-butyl ether, ethylene dichloride, chlorobenzene equal solvent in reactive system, utilize the method for component distillation, constantly sloughs the water that generates in the reaction, promotes reaction to carry out, and suppresses the generation of high boiling material simultaneously.With the acetic acid that accounts for amounts of glycerol 5% is catalyzer, HCl gas about 100 ℃ with glycerine reaction 35h, the molar yield of dichlorohydrine is greater than 87%, essentially no condenses generates.But such technology is difficult to use in industry, because solvent load is big, reduces usage ratio of equipment, and the backflow energy consumption of a large amount of solvents is big, and the HCl gas loss is big, and residual solvent also influences the purity of product, the burden of increase tripping device.
Czech chemical metallurgy affiliated company discloses a kind of continuous circulating reacting process in its patent CN1845888A (or WO2005021476).React in bubbling reactor with HCl gas and glycerine under acetic acid catalysis, reactant enters in the rectifying tower subsequently, steams the water and the dichlorohydrine of generation from cat head, and tower bottoms pumps in the reactor, thereby carries out circulating reaction.Under situation, constantly remove dichlorohydrine and water in the reactant by the rectifying tower in the insertion reaction circulation way, thereby reaction is carried out smoothly without plus solvent.The drawback of having avoided a large amount of use solvents to bring.Yet such technological reaction inefficiency, because reactant continuously enters rectifying in the rectifying tower, normally underpressure distillation makes HCl at first be steamed reaction system, forms spent acid, cause the HCl concentration in the reaction system very low, thereby speed of reaction is low.In addition, underpressure distillation is continuously steamed the catalyst acetic acid major part, causes catalyst levels big.
In addition, Solvay company discloses the similar technology of a kind of and aforementioned Czech chemical metallurgy affiliated company in its patent WO2005054167 (or Fr2862644).React in separate unit or many blistering reaction stills, reactant enters rectifying tower continuously, adopts component distillation to remove the dichlorohydrine and the water of generation, reaction is carried out smoothly, the tower bottoms circulating reaction.Different is the trend of material for this part patent of Solvay company and Czech chemical metallurgy affiliated company patent.HCl gas and liquid reactants are countercurrent flows in the patent of Solvay company, so the HCl utilization ratio improves.In addition, preferred catalyzer is not volatile hexanodioic acid in this patent, so the loss of catalyzer is very little in the material circulating reaction.But this technology remains the energy consumption height, and plant factor is low.
Generally speaking existing technology all is to react in bubbling still (tower) or stirring tank, and HCl concentration is low in the reaction system, and speed of reaction is low.Reactor types has determined reaction efficiency low, the energy consumption height.And inefficient reaction, also easily cause the generation of high boiling material, reduce the selectivity of reaction.
Summary of the invention
For overcoming these shortcomings of prior art, the present invention proposes a kind of method for preparing dichlorohydrine from glycerine.
The reaction that glycerine and HCl reaction generates dichlorohydrine in two steps, reaction formula is as follows:
By the general knowledge of reaction kinetics as can be known, under the situation of initial reaction stage, low-conversion, reaction is not subjected to thermodynamical restriction, the existence that is water is little to the influence of reaction, and the later stage of reaction is under the transformation efficiency condition with higher, reaction is subjected to thermodynamical restriction, the carrying out that has inhibited reaction of water in the reaction system.
Technical scheme of the present invention is:
At first glycerine is added mixing tank with HCl and carboxylic acid catalyst, be pressed into continuously and carry out chlorination reaction in the tubular reactor, through the tubular reactor reaction, glycerine transforms rapidly.Reactant then enters HCl bubbling still and continues reaction.At this, water that reaction generates and dichlorohydrine, HCl and part catalyzer form azeotrope and steam from bubbling still top, reclaim product through condensation, and bubbling still still liquid then enters rectifying tower continuously to be separated, obtain the product dichlorohydrine from rectifying tower top, the rectifying tower bottoms is sent to circulating reaction.
Entering the glycerine of tubular reactor and the mol ratio of HCl is 1:0.5~1:3, preferred 1:1.0~1:2.0, and available glycerol concentration is 85~100%.HCl can be that gas also can be concentration range at 25~38% hydrochloric acid, preferably HCl gas.
Catalyzer is C
1~C
12Carboxylic acid, preferably butyric acid or valeric acid.Catalyst levels accounts for 0.5%~5% of amounts of glycerol, and preferably 1~3%.
There are filler or suitable inner member in the inside of tubular reactor, to guarantee reactant good mixed effect is arranged in flow process.General used filler or the used inner member of static mixer of packing tower can use.
Temperature of reaction in tubular reactor is 80~140 ℃, preferably 95~105 ℃.Too high temperature of reaction can cause burnt shape thing to generate.
Reaction times in tubular reactor is 2h~12h, preferably 4h~6h.
Enter bubbling reactor continuously through the reacted material of tubular reactor and continue reaction, the water of generation and dichlorohydrine and HCl discharge from reactor top continuously.This bubbling reactor can be a stirring-type, tower, also can be to fill pillar or jet-type.Preferably tower bubbling reactor.In the reactor stirring rake or internals can be set,, thereby improve speed of reaction with raising gas-liquid mass transfer effect.
Gas blasts bubbling reactor by gas distributor from the bottom, and available any dispersing method blasts, as porous nozzle, porous ceramic plate etc.The gas that blasts can be pure HCl, and the mol ratio of itself and glycerine is 0.5:1~3:1, preferred 1:1.0~2.0:1.Also can be HCl and other gas mixture by a certain percentage.Here said other gas generally is meant nitrogen, air, carbonic acid gas, argon gas, helium etc. to this reactive system inert gasses, preferably nitrogen or carbonic acid gas.The volume ratio of described rare gas element and HCl is 0~1:1, preferably 0~0.5:1.The use of rare gas element makes the H of generation
2O can in time shift out from reaction system, thereby promotes reaction.
The service temperature of bubbling reactor is at 90~140 ℃, and preferably 105~115 ℃, the residence time of reactant in bubbling reactor is 6~16h, preferably 8~10h.
The combination of reactors method that the present invention proposes is to design according to the characteristics that are reflected at different steps, and speed of reaction is improved, and plant factor improves, and glycerine transforms fully in 12~16h, and the yield of dichlorohydrine can be greater than 90%.Because do not resemble the long-time back flow reaction of needs of prior art, so the HCl utilization ratio is increased to more than 70%, energy consumption reduces greatly.
Description of drawings
Fig. 1 structural representation of the present invention
1. mixing tank 2. fresh feed pumps 3. tubular reactors 4,11. sampling valves 5,12. flowrate control valves
6. bubbling reactor 7. gas distributors 8,15. condensers 9,16. bleeder valves 10. tail gas condensate drums
13. rectifying tower 14. overhead product jars 17. still liquid recycle pumps
Tubular reactor among the figure (3) is a polytetrafluoroethylene (PTFE) coil pipe, fills some ceramic rings in the pipe, the having of reactor The about 400ml of effect volume, reactor places oil bath, and reactor outlet has a flow control valve (5) in order to the conditioned reaction device Internal pressure.
Bubbling still reactor among the figure is a glass reactor, i.e. bubbling column reactor (6), effective reacting volume about 900 Ml, HCl gas passes into from the bottom by gas distributor (7). The bubble tower lower part outlet has a flow control valve (12) In order to the conditioned reaction thing time of staying. Reactant liquor CaCO3Carry out decompression distillation after the neutralization, from overhead collection product dichlorohydrin and a small amount of H2The azeotropic mixture of O and dichlorohydrin.
Embodiment
Example 1. with glycerine (95% industrial goods) with 0.6mol/h (acetic acid that wherein comprises catalyzer 2%) and HCl (by PCl
3With H
2O presses the 1:3.5 reaction and produces) with 0.6mol/h.Squeeze into pump in the reactive system shown in Figure 1 through pre-mixing, 105 ℃ of tubular reactor oil bath temperatures are regulated by rate of discharge variable valve 5, and making material residence time in tubular reactor is 6h.By sampling valve 4 sampling gas chromatographic analysiss as can be known, glycerol conversion yield 93.6%, glycerine monochlorohydrin production rate 84.4%, dichlorohydrine production rate 8.9%.NaOH labeling response liquid acid concentration 0.49mol/L.
The effusive reaction solution of tubular reactor directly enters the HCl bubbling column reactor, temperature of reaction is controlled to be 108 ℃, the feeding amount of HCl is 1.2mol/h, and controlling the residence time of material in bubbling reactor by outlet valve 12 Flow-rate adjustment is that (excessive HCl discharges from reactor with azeotrope 10h.Azeotrope consists of: 19.6% dichlorohydrine, 30.4% HCl, 48% H
2O, 2% acetic acid).By sampling valve 11 samplings, reaction solution sample CaCO
3Fully carry out gas chromatographic analysis after the neutralization again: glycerine monochlorohydrin 21.6%, 1,3-dichloroisopropanol 77.1%, 2,3-dichloro n-propyl alcohol 0.6% (1,3-dichloroisopropanol and 2,3-dichloro n-propyl alcohol does not have difference for generating epoxy chloropropane, so hereinafter no longer distinguish the general designation dichlorohydrine), all the other (comprising condenses) are 0.7%.With NaOH drop reaction liquid acid concentration is 0.45mol/L.
Behind the continuously feeding 10h, reactive system enters steady state operation.In the 5h of steady state operation, glycerine (95%) charging 295g (3mol), HCl charging 9mol, glycerine transforms fully.Get phlegma 187.6g (wherein containing dichlorohydrine 37.6g, HCl 56.3g, water 89.7g, acetic acid 4g) from the condensation of bubbling reactor tail gas.Dichlorohydrine from rectification under vacuum overhead collection 30~32 ℃/15mmHg dichlorohydrine and water azeotrope and 70~72 ℃/15mmHg obtains 352.6g altogether, wherein moisture 33g, dichlorohydrine 319.6g.Dichlorohydrine yield 92.3% (based on glycerine).
Example 2. changes material residence time in bubbling reactor.Industry glycerol (95%) is pumped in the reactive system shown in Figure 1 through pre-mixing with 0.6mol/h with 0.6mol/h (2% acetic acid is made catalyzer in wherein containing) and HCl, 100 ℃ of tubular reactor oil bath temperatures, by the top hole pressure Flow-rate adjustment, material residence time in tubular reactor is 6h.
The temperature of control bubbling reactor is 110 ℃, regulates rate of discharge, and making the residence time of material in bubbling reactor is 7h, and the feeding amount of HCl is 0.8mol/h, the azeotrope of generation with the tail gas condensation after gas-liquid separation collect.
In the 5h of steady state operation, glycerine feed 295g (3mol), HCl charging 9mol, glycerine transforms fully.Get phlegma 198g (wherein containing dichlorohydrine 39.1g, HCl 62g, water 91.8g, acetic acid 5.2g) from the condensation of bubbling reactor tail gas.Dichlorohydrine from rectifying tower top collection 30~32 ℃/15mmHg dichlorohydrine and water azeotrope and 70~72 ℃/15mmHg obtains 338g, wherein moisture 26.3g, dichlorohydrine 311.7g, dichlorohydrine yield 90.6% altogether.
Example 3. changes material residence time in tubular reactor.Industry glycerol (95%) is with 1.0mol/h (containing 2% acetic acid), HCl 1.0mol/h charging, 105 ℃ of control tubular type temperature of reactor, about 3.5h of the residence time of material in tubular reactor, tubular reactor outlet glycerol conversion yield 81.6, glycerine monochlorohydrin production rate 79.2, dichlorohydrine production rate 2.0%.NaOH demarcates acid number 1.4mol/L.
The reaction solution of tubular reactor enters the HCl bubbling reactor and continues reaction, and HCl feeding amount is 2mol/h, 110 ℃ of control blistering reaction actuator temperatures, residence time 10h.
In the 5h of steady state operation, glycerine feed 5mol, HCl charging 15mol, glycerine transforms fully.Get phlegma 257.2g from the condensation of bubbling reactor tail gas, wherein contain dichlorohydrine 50.8g, H
2O 122g, HCl 77.6g, acetic acid 6.8g.Dichlorohydrine from rectifying tower top collection 30~32 ℃/15mmHg dichlorohydrine and water azeotrope and 70~72 ℃/15mmHg obtains 514.8g altogether, wherein contains dichlorohydrine 469.8g, H
2O 45g.Dichlorohydrine yield 80.7%.
The temperature of reaction of example 4. control tubular reactors is 95 ℃, and all the other are operated with example 1, and reaction result is listed in table 1.
Example 5. bubbling reactors are with 0.8mol HCl/h+0.6mol N
2/ h mixed gas bubbling, all the other are operated with example 1, and reaction result is listed in table 1.
Example 6. bubbling reactors are with 0.8mol HCl/h+0.6mol CO
2/ h mixed gas bubbling, all the other are operated with example 1, and reaction result is listed in table 1.
115 ℃ of example 7. blistering reaction actuator temperatures controls, all the other are with example 1, and reaction result is listed in table 1.
Contain 2% valeric acid in example 8. glycerin fed and make catalyzer, all the other are with example 1, and reaction result is listed in table 1.
Example 9. glycerin fed content be 99% analytical pure glycerine reagent to replace content be 95% industry glycerol, all the other are with example 1, reaction result is listed in table 1.
Example 10. usefulness 1000ml replace bubbling column reactor among Fig. 1 with churned mechanically glass flask, and with siphonage discharging at the bottom of the bottle, all the other are with example 1, and reaction result is listed in table 1.
Example 11. changes tubular reactor charging proportioning.With industry glycerol (95%) with 0.6mol/h (2% acetic acid is made catalyzer in wherein containing) and HCl with 0.3mol/h through the pre-mixing charging, material residence time in tubular reactor is 7.5h.All the other are with example 1, and reaction result is listed in table 1.
Example 12. changes tubular reactor charging proportioning.With industry glycerol (95%) with 0.6mol/h (2% acetic acid is made catalyzer in wherein containing) and HCl with 1.2mol/h through the pre-mixing charging, material residence time in tubular reactor is 5.5h.All the other are with example 1, and reaction result is listed in table 1.
In the example 13. tubular reactor chargings be 36% salt acid substitution HCl gas with concentration.With industry glycerol (95%) with 0.6mol/h (2% acetic acid is made catalyzer in wherein containing) and concentration be 36% hydrochloric acid with 0.6mol/h through the pre-mixing charging, material residence time in tubular reactor is about 3.7h.All the other are with example 1, and reaction result is listed in table 1.
Reference examples: according to the WO2005054167 of Solvay house journal (or Fr2862644) method, in the four-hole boiling flask of the 1000ml that is with mechanical stirring, tail gas condenser and gas duct, add 453g glycerine (4.92mol) and 29.5g Glacial acetic acid (0.49mol), be heated to 110 ℃, feeding HCl gas reacts, feed 2h with 5.2molHCl/h earlier, then with the logical 100min of 3.8mol HCl/h, at last with the logical 380min of 1.3mol HCl/h.Amount to and feed 25.0mol HCl.Total reaction time is 10h.Glycerine transforms fully, and tail gas phlegma and rectifying product the results are shown in table 1.
Table 1 changes operational condition experimental result (mass unit: gram)