CN103333073B

CN103333073B - Process for preparing N,N-dimethyl-1,3-propane diamine through continuous method

Info

Publication number: CN103333073B
Application number: CN201310254600.6A
Authority: CN
Inventors: 孟庆伟; 邓朝芳; 都健; 李亚楠; 卿海
Original assignee: Dalian University of Technology
Current assignee: Dalian University of Technology
Priority date: 2013-06-24
Filing date: 2013-06-24
Publication date: 2015-06-24
Anticipated expiration: 2033-06-24
Also published as: CN103333073A

Abstract

The invention discloses a process for preparing N,N-dimethyl-1,3-propane diamine through a continuous method and belongs to the field of organic chemical industry. The process comprises the following steps: by taking dimethylamine and acrylonitrile as raw materials, continuously preparing dimethylamino propionitrile by employing a fixed bed, wherein the molar ratio of dimethylamine to acrylonitrile is (10:1)-(1:1), the reaction temperature is 10-120 DEG C, the air speed is 0.1-10h<-1>, and the conversion rate of the acrylonitrile and the selectivity of the dimethylamino propionitrile are over 99 percent; and allowing the obtained dimethylamino propionitrile intermediate to directly enter a second fixed bed reactor for hydrogenating without any purification treatment, wherein the hydrogenation pressure is 3-10 MPa, a Raney-Ni catalyst is used, an alcoholic solution promoter with 0.1-10 percent of alkali is matched, the air speed is 0.1-4h<-1>, and the yield of N,N-dimethyl-1,3-propane diamine is not lower than 93 percent. The process for preparing N,N-dimethyl-1,3-propane diamine is simple, stable in quality, energy-saving and environment-friendly and is suitable for large-scale production.

Description

A kind of continuous processing prepares N, the technique of N-dimethyl-1,3-propylene diamine

Technical field

The invention belongs to field of chemical technology, relate to a kind of continuous processing and prepare N, the technique of N-dimethyl-1,3-propylene diamine

Background technology

N, N-dimethyl-1,3-propylene diamine belongs to lower aliphatic diamines, is a kind of important chemical intermediate, is widely used in and prepares sanitising agent, tensio-active agent, textiles, lubricating oil additive, gasoline dope, sanitas, moistening agent, whipping agent etc.Along with progress that is scientific and technological and social development, the range of application of DMAPA is also corresponding constantly to be expanded, and the market requirement also increases year by year.Therefore, N, N-dimethyl-1,3-propylene diamine is a kind of organic chemical industry's intermediate very with application potential.

The preparation method of N, N-dimethyl-1,3-propylene diamine mainly contains two kinds.The first is with vinyl cyanide and dimethylamine for raw material, preparation N, N-dimethyl-1,3-propylene diamine; Another kind is for raw material prepares N, N-dimethyl-1,3-propylene diamine with propenal and dimethylamine.

First method (CN101321722A) be with vinyl cyanide and dimethylamine for raw material, after hydrogenation, prepare N, N-dimethyl-1,3 propylene diamine.What this method adopted is batch tank hydrogenation, and catalyzer is Raney-Ni, and under the aqueous solution of caustic alkali exists, hydrogen pressure is about 3MPa, temperature of reaction 90 DEG C, and the yield of final N, N-dimethyl-1,3-propylene diamine is about 93%.This method is the still of interval is hydrogenation, and need the non-productive operation of handling material, reactor back mixing phenomenon after the meeting, reacts more difficult and reach very high selectivity.

Second method (CN102026956A) is that 0 ~ 3MPa is obtained by reacting N, N with propenal and dimethylamine at 4 DEG C, N ', 1,3-Pn of N '-replacement, the mixture obtained and ammonia and hydrogen are in the presence of a catalyst at 40 ~ 400 DEG C, N is obtained by reacting under 6MPa, N-dimethyl-1,3-propylene diamine, its yield is about 91%, the method environmental protection, but yield comparatively first method is low.

Summary of the invention

The N that the problem that the present invention solves is to provide that a kind of technique is simple, low cost, selectivity are high and be easy to realize continuous prodution, the preparation method of N-dimethyl-1,3-propylene diamine.

Technical scheme of the present invention is as follows:

By the dimethylamine of mol ratio 10:1 ~ 1:1 and vinyl cyanide in fixed-bed reactor, reaction pressure is 0.1 ~ 8MPa, temperature of reaction 10 ~ 120 DEG C, and cumulative volume air speed is 0.1 ~ 10h ^-1condition under reaction prepare dimethylaminopropionitrile, acrylonitrile conversion rate is more than 99.5%, and the selectivity of dimethylaminopropionitrile is more than 99.5%.Dimethylaminopropionitrile obtained for the first step can be directly fixed bed hydroprocessing reaction without any purifying, and hydrogenation pressure is 2 ~ 12MPa, uses Raney-Ni catalyzer, is furnished with the alkali alcosol promotor of 0.1% ~ 40%, air speed 0.1 ~ 4h ^-1scope in, the productive rate productive rate of N, N-dimethyl-1,3-propylene diamine is not less than 98%, and this technique prepares N, and N-dimethyl-1,3-propylene diamine technique is simple, and steady quality, green, power consumption are less, cost is low, be applicable to scale production.

When dimethylaminopropionitrile prepared by fixed-bed reactor, the filler of filling in fixed-bed reactor is any inert solid fillers not with dimethylamine and acrylonitrile reactor, comprise glass filler, Stainless Steel Helices, quartz sand, plastic filler, ceramic packing and molecular sieve, aluminum oxide, one or more the mixture in silica gel; Form has regular and loose heap, and the shape of random packing is saddle type, spherical, ring-like, strip.

When dimethylaminopropionitrile reaction prepared by fixed-bed reactor, the volume space velocity of reaction is 0.1 ~ 10h ^-1, the temperature of reaction is 10 ~ 120 DEG C, and the pressure of reaction is 0.1 ~ 8.0MPa.

When dimethylaminopropionitrile prepared by fixed-bed reactor, dimethylamine and vinyl cyanide mol ratio 10:1 ~ 1:1 scope.

Fixed bed continuous hydrogenation the first step product dimethylaminopropionitrile prepares N, and during the technique of N-dimethyl-1,3-propylene diamine, filling hydrogenation catalyst is Raney-Ni catalyzer, the air speed 0.1 ~ 4h of reaction ^-1, the pressure of hydrogenation is 2.00 ~ 12.0MPa, and the temperature of hydrogenation is 10 ~ 200 DEG C.

Fixed bed continuous hydrogenation the first step product dimethylaminopropionitrile prepares N, and during the technique of N-dimethyl-1,3-propylene diamine, promotor is one of the methyl alcohol of NaOH, KOH, CsOH, LiOH, ethanol or the aqueous solution and composition thereof, and concentration is 0.1 ~ 40%.

When dimethylaminopropionitrile is prepared in the first step methylamine reaction of the present invention, take cost low, the inert fillers such as the stainless steel that the life-span is long, and the selectivity of the transformation efficiency of vinyl cyanide and dimethylaminopropionitrile is all higher than 99%, dimethylaminopropionitrile obtained for the first step can be directly fixed bed hydroprocessing reaction without any purifying or separation and prepare N, N-dimethyl-1, 3-propylene diamine, what add in second step hydrogenation reaction is alkali alcosol, the ability that alcohols transmits hydrogen is stronger, and easily remove, and two-step reaction is all the fixed-bed reactor adopted to be operated, be easy to realize continuous prodution, technique is simple, cost is low, the three wastes are few, be suitable for suitability for industrialized production.

Accompanying drawing explanation

Accompanying drawing is structure of reactor schematic diagram used of the present invention.

In figure: 1 steel cylinder (nitrogen); 2 ball valves; 3 tensimeters; 4 non-return valves; 5 raw material blow-off valves; 6 drying tubes; 7 double plunger micro pumps; 8 steel cylinders (dimethylamine); 9 reagent bottles (vinyl cyanide); 10 methylamine reactors; 11 gas-liquid separators; 12 sampling valves; 13 constant pressure valves; 14 back pressure valves; 15 temperature controllers; 16 container for storing liquids (dimethylaminopropionitrile); 17 reagent bottles (alkali lye); 18 steel cylinders (hydrogen); 19 hydrogenators; 20 container for storing liquids (N, N-dimethyl-1,3-propylene diamine).

Specific implementation method

Describe specific embodiments of the invention in detail below in conjunction with accompanying drawing and technical scheme, but processing condition are not limited only to these embodiments.

Embodiment 1:

Continuous processing prepares N, N-dimethyl-1, the process flow sheet of 3-propylene diamine as shown in Figure 1, (A) full filler is inserted by reactor 10, the temperature 30 DEG C of setting experimental pressure 1MPa and reaction, then, use double plunger micro pump 8 and double plunger micro pump 9 by dimethylamine and acrylonitrile 1:50:1.00 and air speed 2h in molar ratio respectively ^-1simultaneously be sent to reactor 10 from the top of device, reaction solution cools through gas-liquid separator 11, runs about 4h, carries out gas phase analysis, the transformation efficiency 99.6% of acrylonitrile and the selectivity 99.5% of dimethylaminopropionitrile by sampling valve 12 liquid that takes a morsel.The dimethylaminopropionitrile of preparation is loaded in container for storing liquid 16, directly hydrogenation reaction is carried out without any process, (B) first in reaction tubes 19, Raney-Ni catalyzer is filled up, the pressure 6MPa of setting hydrogen, 0.5%NaOH methanol solution and dimethylaminopropionitrile are sent to reactor 19 from the bottom of device by double plunger micro pump 8 and double plunger micro pump 9 simultaneously, air speed 0.3h ^-1fate row 4h is carried out in device sampling, reaction solution cools through gas-liquid separator 11, gas phase analysis is carried out by sampling valve 12 liquid that takes a morsel, the transformation efficiency 99.8% of dimethylaminopropionitrile and N, the productive rate of N-dimethyl-1,3-propylene diamine is higher than 98.0%, and the N that will obtain, N-dimethyl-1,3-propylene diamine is stored in storage tank 20.

Embodiment 2 ~ 15

As can be seen from institute's embodiment, higher transformation efficiency and selectivity or productive rate can be realized in a wider conditions.Therefore, this technique prepares N, and N-dimethyl-1,3-propylene diamine technique is simple, and steady quality, green, power consumption are less, cost is low, be applicable to scale production.

Claims

1. a continuous processing prepares N, N-dimethyl-1, the technique of 3-propylene diamine, it is characterized in that with fixed-bed reactor, with dimethylamine and vinyl cyanide for raw material, in mol ratio, temperature of reaction, under pressure and air speed, any catalyzer successive reaction is not adopted to prepare dimethylaminopropionitrile, acrylonitrile conversion rate is not less than 99.5%, the productive rate of dimethylaminopropionitrile is more than 99%, the dimethylaminopropionitrile intermediate the first step prepared again directly enters second fixed-bed reactor without any purification process and carries out hydrogenation, take Raney-Ni as hydrogenation catalyst, at hydrogen pressure, temperature, under air speed and promotor exist, continuous production N, N-dimethyl-1, 3-propylene diamine productive rate is not less than 98%,

During the first step fixed-bed reactor continuous production dimethylaminopropionitrile, do not adopt any catalyzer, the filler of filling in fixed-bed reactor is any inert solid fillers not with dimethylamine and acrylonitrile reactor, described inert solid fillers is glass filler, one or more the mixture in Stainless Steel Helices, quartz sand, plastic filler, ceramic packing, molecular sieve, aluminum oxide, silica gel; Form has regular and loose heap, and the shape of random packing is saddle type, spherical, ring-like, strip;

During the reaction of the first step fixed-bed reactor continuous production dimethylaminopropionitrile, the volume space velocity of reaction is 0.1 ~ 10h ^-1; During the reaction of the first step fixed-bed reactor continuous production dimethylaminopropionitrile, the temperature of reaction is 10 ~ 120 DEG C, and the pressure of reaction is 0.1 ~ 8.0MPa;

During the reaction of the first step fixed-bed reactor continuous production dimethylaminopropionitrile, the feed molar proportioning of dimethylamine and vinyl cyanide is 10:1 to 1:1.

2. technique according to claim 1, it is characterized in that second fixed bed continuous hydrogenation the first step product dimethylaminopropionitrile prepares N, N-dimethyl-1, during the technique of 3-propylene diamine, hydrogenation catalyst filled by fixed bed is Raney-Ni catalyzer, and the volume space velocity of the raw material dimethylaminopropionitrile of hydrogenation is 0.1 ~ 4.0h ^-1;

Second fixed bed continuous hydrogenation the first step product dimethylaminopropionitrile prepares N, and during the technique of N-dimethyl-1,3-propylene diamine, the pressure of hydrogenation is 2.00 ~ 12.0MPa, and the temperature of hydrogenation is 10 ~ 200 DEG C.

3. technique according to claim 1 and 2, it is characterized in that, second fixed bed continuous hydrogenation the first step product dimethylaminopropionitrile prepares N, N-dimethyl-1, during the technique of 3-propylene diamine, promotor is one of the methyl alcohol of NaOH, KOH, CsOH, LiOH, ethanol or the aqueous solution and composition thereof; Second fixed bed continuous hydrogenation the first step product dimethylaminopropionitrile prepares N, and during the technique of N-dimethyl-1,3-propylene diamine, the methyl alcohol of NaOH, KOH, CsOH, LiOH, ethanol or concentration of aqueous solution are 0.1 ~ 40%.