CN1065655A - Making with extra care of diglycol monotertiary butyl ether - Google Patents

Abstract

The process for purification of a kind of diglycol monotertiary butyl ether (MBE) is with glycol ether (DEG) and C ₄Cut raffinate (SBB) is in synthetic diglycol monotertiary butyl ether (MBE) process of raw material, and monoether of etherificate product (MBE) and bis ether (DBE) can form azeotrope, and azeotrope and MBE boiling point are quite approaching.Adopt general rectificating method to separate and be difficult to obtain highly purified MBE, add the azeotropic distillation flow process that water is made entrainer and adopt, then can reach the high separation of MBE and DBE, both all reach more than 98% purity.

Description

Making with extra care of diglycol monotertiary butyl ether

The present invention is the process for purification of a kind of diglycol monotertiary butyl ether (MBE).

Glycol ether (DEG) and C ₄Fraction divinyl raffinate (SBB) is in synthetic diglycol monotertiary butyl ether (MBE) process of raw material, the etherificate product mixtures that comes out from reactor, except that containing purpose product MBE, also comprise by product glycol ether dual-tert-butyl ether (DBE) and unreacted DEG, SBB.Liquid phase etherificate composition sees Table 1.

For with the MBE in the etherificate product, DBE, SBB and DEG be Separation and Recovery one by one, according to the boiling-point difference that each component exists, can adopt general distillating method to separate.But when adopting general distillating method to separate, MBE and DBE can form azeotrope.And the boiling point of MBE-DBE azeotrope and MBE is quite approaching, is difficult to obtain highly purified MBE.

According under absolute pressure 8.0KPa to MBE-DBE, the vapor-liquid equilibrium data measurement result such as the table 2 of MBE-DEG two-component system, shown in the table 3, MBE and DBE can form minimum azeotropic mixture as can be known from the vapor-liquid equilibrium data that records, the boiling point of this azeotrope is 133.9 ℃ under absolute pressure 8.0KPa, therefore MBE can not separate with general distillating method with DBE, and MBE-DBE azeotrope and MBE boiling point are quite approaching, both boiling points only differ from 1.6 ℃ under absolute pressure 8.0KPa, are difficult to a small amount of MBE-DBE azeotrope is separated from MBE.If both energy delamination then except that obtaining highly purified MBE product, are returned azeotrope in the etherificate system, can play the effect that suppresses the DBE formation reaction, when 50 ℃ of etherification reaction temperatures, when DBE content was the different twenty alkene mole number 8% of raw material, the DBE formation reaction was almost ended.But another reason that can not adopt this separation process is that MBE content is higher in the azeotrope, returns the etherification reaction system, equally also will suppress to form the main reaction of MBE.

MBE and DEG relative volatility are very big, and from recording data under absolute pressure 8.0KPa, the boiling-point difference of MBE and DEG is 33.1 ℃, and can not form azeotrope, so rectification under vacuum is very easy in both separation.

The objective of the invention is to select for use an energy and DBE and MBE to form the entrainer of ternary azeotropic, and this entrainer should have and can dissolve each other and the characteristic of indissoluble DBE with MBE.So just can accomplish that MBE and the effective of DBE separate.

In azeotropic distillation, record water, the composition of DBE and MBE azeotrope is as shown in table 3.Water and oil phase composition is listed in table 4 after the azeotrope layering.

Because water-DBE-MBE ternary azeotropic temperature (99 ℃) is significantly less than MBE(212 ℃), therefore with water as entrainer, it is effective adopting the azeotropic distillation method to separate DBE.

The azeotropic distillation technology of interpolation entrainer provided by the invention can contrast Fig. 1 etherificate product separation process synoptic diagram and be illustrated.The etherificate product that reactor comes out adds less water, with etherificate product ratio be 0.018～0.03: 1(adds water can reduce tower still temperature).

In pressure distillation tower (1), remove unreacted SBB, import then in the atmospheric distillation tower (2) and carry out component distillation, deviate from DBE.It is water that cat head steams thing, and the azeotropic mixture that DBE and MBE form after condenser (7) cooling liquid, is separated into oil reservoir and water layer two-phase, the water total reflux in liquid-liquid separation jar (6).The oil phase of rich DBE is sent into simple distillation tower (4) distillation, and overhead product is the mixture of water and a small amount of DBE and MBE composition, rework solution-liquid separating tank (6); The tower still then obtains highly purified DBE byproduct.Tower (2) still liquid mainly is MBE and DEG, is introduced into tower (3) underpressure distillation, and overhead product is highly purified MBE finished product.Remaining system reclaims DEG at the bottom of the tower, and it after vaporization becomes not chalybeate fraction, returns the etherification reaction systemic circulation and use in simple distillation tower (5).

Because DBE content is heavy less than 2.5%(in the etherification reaction product), therefore when requiring the MBE of 98% above purity, the user can will not remove the tower 1 still liquid of SBB without tower 2, directly enter tower 3 underpressure distillation by bypass, obtain MBE and DBE mixture as product by cat head, MBE purity＞95%.

Adopt above-mentioned flow process, can get purity＞98% or＞95%(is heavy) MBE, DBE also can be used as byproduct and obtains, it is heavy that its purity can reach 98%(), SBB reclaims as liquefied gas; DEG reclaims the back as charging.Therefore, this flow process is to adjust flexibly, can obtain the MBE's of different purity effectively.

In addition, batch fractionating separates the etherificate product, adopts interpolation water to make entrainer and also can obtain the MBE of purity more than 98%.

Following example will further specify implementation method of the present invention.

Example 1

Experimental installation by Fig. 1 record take off DBE tower (2) and take off MBE tower (3) separating resulting as follows:

Take off DBE tower P=1.013 * 10 ⁶

Operational condition: t _D=98 ℃, t _W=108～115 ℃

Add H ₂O295g(300ml)

Charging F=9917g

Form: impurity 6.8217

DBE 1.3041

MBE 41.4132

DEG 50.4607

Cat head D=309.5g

Form: H ₂O 97.6546

DBE 1.5691

MBE 0.573

DEG 0.2031

The tower still

Form: impurity 1.1763

DBE 0.1479

MBE 44.871

DEG 53.8043

Take off MBE tower P=2.27 * 10 ⁸～2.67 * 10 ³Pa

Operational condition: t _D=86～87 ℃, t _W=152～156 ℃

Charging F=967g

Form: impurity 0.2570

DBE 0.1063

MBE 45.8395

DEG 53.6880

Cat head D=437.4g

Form: impurity 0.2570

DBE 0.1063

MBE 99.6365

Tower still W=521g

Form: impurity 0.4741

DBE 0.09

MBE 0.1746

DEG 98.7612

Example 2

Testing apparatus by Fig. 1 record take off DBE tower (2) and take off MBE tower (3) separating resulting as follows:

Take off DBE tower normal pressure

Operational condition: t _D=98 ℃, t _W=109～112 ℃

Add H ₂O235g(240ml)

Charging F=1010g

Form: impurity 6.8217

DBE 1.3041

MBE 41.4132

DEG 50.4607

Cat head D=254.1g

Form: H ₂O 97.7433

DBE 1.7026

MBE 0.4377

DEG 0.1162

Tower still W=985.9g

Form: impurity 1.5969

DBE 0.1456

MBE 44.7279

DEG 53.5294

Take off MBE tower P=1.33 * 10 ³～2.0 * 10 ⁸Pa

Operational condition: t _D=82～84 ℃, t _W=152～154 ℃

Charging F=995g

Form: impurity 0.3941

DBE 0.2274

MBE 45.3395

DEG 54.0389

Cat head D=450.4g

Form: impurity 0.5176

DBE 0.2636

MBE 99.2186

Tower still W=538g

Form: impurity 0.2908

DBE 0.1971

MBE 0.2331

DEG 99.2789

Annotate: above and later composition is peak area percentage ratio

Example 3

Azeotropic distillation takes off DBE continuously, and each inventory distributes as following table

Operational condition: pressure, MPa 0.101

Tower top temperature, ℃ 99.9

Column bottom temperature, ℃ 219.5

Quantity of reflux, Kg/hr 36.22

Example 4

The vacuum continuous rectification separates the MBE product, and each inventory distributes as following table

Tower top temperature, ℃ 118

Column bottom temperature, ℃ 178

Quantity of reflux, Kg/hr 10.52

Reflux ratio 4.2

The composition of table 1 liquid phase etherificate product

The component boiling point, ℃ content, %(is heavy)

Carbon four-6.5 1～2

Unknown material～0.25

Impurity (DEG brings into)～1

DBE 223 1～2.5

MBE 212 45.0～50.0

DEG 246 47.0～50.0

Temperature-composition (T-X-Y) of table 2 MBE and DBE

Test number	Solution boiling point T, ℃	MBE mole fraction X in the liquid phase	MBE mole fraction Y in the gas phase
				D-29 D-28 D-39 D-26 D-25 D-24 D-23 D-22 D-21 D-20 D-19 D-18 D-16 D-14 D-13 D-34 D-31 D-32 D-30 D-1	143.5 143.1 142.4 141.9 141.5 141.0 140.5 139.4 138.7 137.6 137.0 136.6 135.6 135.0 134.6 134.2 134.7 134.8 134.9 135.5	0.000 0.035 0.080 0.120 0.140 0.170 0.185 0.230 0.260 0.305 0.360 0.395 0.505 0.605 0.670 0.845 0.912 0.925 0.943 1.000	0.000 0.040 0.098 0.155 0.180 0.230 0.260 0.325 0.365 0.420 0.452 0.495 0.580 0.655 0.712 0.820 0.880 0.890 0.910 1.000

Pressure: 8.0KPa(is exhausted)

Temperature-composition (T-X-Y) of table 3 MBE and DEG

Test number	Solution boiling point T, ℃	MBE mole fraction X in the liquid phase	MBE mole fraction Y in the gas phase
				E-1 E-14 E-13 E-12 E-11 E-8 E-7 E-16 E-17 E-15 D-1	168.6 168.3 167.9 164.4 162.0 155.3 148.3 143.3 141.7 136.6 135.5	0.000 0.008 0.010 0.030 0.065 0.142 0.270 0.490 0.560 0.955 1.000	0.000 0.072 0.115 0.515 0.625 0.748 0.835 0.880 0.895 0.985 1.000

Pressure: 8.0KPa(is exhausted)

Table 4 water, DBE and MBE ternary azeotropic are formed

Azeotropic component is formed, %(weight)

Water 97.9

DBE 1.7

MBE 0.4

* normal pressure, 99 ℃ of azeotropic temperatures

The water of table 5 ternary azeotrope, oily two phase composites

Component is formed, and %(is heavy)

The water oil phase

Water 99 25.7

DBE 0.2 73.7

MBE 0.3 0.6

* room temperature lower leaf

Claims (7)

1, glycol ether (DEG) and the C that contains iso-butylene ₄Fraction (SBB) is characterized in that adopting the two tower azeotropic distillation flow processs of adding entrainer through the separation and refining method of the etherify reaction mixture of interruption or successive reaction generation, reaches the method for the smart MBE of MBE and DBE high separation.

2, the method for claim 1 is characterized in that described entrainer is a water.

3, method as claimed in claim 2, the consumption that it is characterized in that described its agent water that boils are 100～300ml/1000ml etherificate product.

4, the method for claim 1 is characterized in that DBE knockout tower (2) temperature is controlled at 108～115 ℃ of tower still temperature, 98 ℃ of tower top temperatures.

5, the method for claim 1, the working pressure that it is characterized in that DBE knockout tower (2) is a normal pressure.

6, the method for claim 1 is characterized in that the temperature of taking off monoether tower (3) is controlled at 84～212 ℃ of tower top temperatures, 152～245 ℃ of tower still temperature.

7, the method for claim 1, the working pressure that it is characterized in that taking off the monoether tower is 1.33 * 10 ³～1.013 * 10 ⁶Pa.

Images