CN1163883A - Utilization of residue in DMT refining process - Google Patents
Utilization of residue in DMT refining process Download PDFInfo
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- CN1163883A CN1163883A CN 96104753 CN96104753A CN1163883A CN 1163883 A CN1163883 A CN 1163883A CN 96104753 CN96104753 CN 96104753 CN 96104753 A CN96104753 A CN 96104753A CN 1163883 A CN1163883 A CN 1163883A
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Abstract
A process for comprehensive utilization of waste (also known as residual dregs) generated after distillation of crystallizing mother liquor of dimethyl tere-phthalate (DMT) during production of DMT includes such technological steps as: pre-treating, ester exchange reaction and post-treatment of coarse ester to obtain esterified substance which is used as plasticizer of plastics.
Description
The present invention relates in a kind of dimethyl terephthalate (DMT) (DMT) production process a kind of method of comprehensive utilization of the waste that the DMT crystalline mother solution is produced (being commonly called as residual II I in the industrial production) after distillation.
Prestige is stepped on (Witten) explained hereafter DMT process and mainly comprised: (I) p-Xylol (PX) and methyl p-methyl benzoate (PTE) merge oxidation, (II) oxide compound esterification, (III) thick ester distillation, (IV) thick DMT carries out operations such as crystal refining in methanol solution.In these several operations, two kinds of residues of main generation: a kind of is that this residue of distillation residue (being commonly called as residue I or IV) that produces in the thick ester distillation of operation (III) accounts for 3～7% of DMT (W) amount, its composition is very complicated, is made up of kind of ester, acid, ether, aldehydes high boiling point polymkeric substance or monomer surplus 40.For the comprehensive utilization of residue I, made lot of research both at home and abroad.The method that JP discloses clear 56-142244 to be provided be with this residue and carbon atoms 4-20 and at least the alcohol of valency carry out transesterification reaction, obtain dun heavy-gravity resultant, this resultant can be used as phthalic acid type softening agent.And for example the method that provides of CN87102846A is that residue I and binary or trivalent alcohol are carried out transesterification reaction, and then carries out polycondensation, dissolution with solvents; Add linking agent at last and make polyester insulating lacquer.
Another kind of residue is the residue (being commonly called as residual II I) that operation (IV) DMT crystalline mother solution is produced after distilling, and this residue accounts for 0.8～1.2% of DMT amount.Mainly form, mainly contain DMT15～30%, DMI40～50%, DMO3.0～8.0% by isomer and a small amount of other impurity of DMT.When DMT content＞15%,, generally raffinate is returned crystallizer crystallization again in order to extract DMT wherein; When DMT＜15%, this part raffinate just no longer utilizes, and burns but this part raffinate acted as a fuel.In order to make full use of this part residue, how residue is further separated at present, isolate DMT, DMI, DMO, utilize respectively.But separating technology is very numerous and diverse, has increased cost greatly, and is unreasonable from saying economically, has not yet to see the most economical approach report that utilizes of relevant residual II I.
The purpose of this invention is to provide the comprehensive utilization process method of a kind of new residual II I, products therefrom can be used as plastic plasticizer.
Comprehensive utilization process method provided by the invention comprises the residue pre-treatment, the reaction of transesterify alcohol, thick three operations of ester aftertreatment.
The residue pre-treatment: with the crystalline mother solution of DMT, the residual II I of gained after distilling, further (negative pressure, absolute pressure are that 6～200mmHg) fractionation by distillation become＜180 ℃ of cuts, 180 ℃～240 ℃ cuts, three parts of＞240 ℃ of cuts by decompression again; First part sends the crystallization again of DMT production system back to, and third part discards, and second section is as the raw material of transesterification reaction.
Transesterification reaction: transesterification reaction is carried out in reactor, and reactor is provided with agitator, and thermometer, condenser, well heater and add C by a certain percentage after adding raw material in the still
4Or C
4Above pure and mild catalyzer, warming while stirring has risen to liquid methanol until temperature and has steamed, stable heating, when waiting to distillate liquid measure near the methyl alcohol theoretical amount, reaction terminating obtains thick ester.
Reacting used catalyzer can be 0.05～0.1% of isomer weight for 1. an acidic catalyst (as sulfuric acid, phosphoric acid etc.) add-on.2. the compound of aluminium is as Al
2O
3, sodium aluminate etc., add-on is 0.05～1%.3. alkaline earth metal oxide, as zinc oxide, magnesium oxide, tin protoxide etc., add-on is 0.1～1%.4. acetate, as zinc acetate, magnesium acetate, calcium acetate etc., add-on is generally 0.1～1%.5. titanate ester, the catalyzer add-on is generally 0.1～1%.Preferably use acetate and titanate ester.
Product postprocessing working procedures: thick ester is put into the conical vessel that opening is arranged at a bottom, and the adding strength of solution is 5～15% Na
2CO
3Solution, volume is 1～2 times of thick ester volume, temperature remains on 70 ℃, stirs standing demix 30～60 minutes, after isolating the waste lye of bottom, clean thick ester till washing water PH=7～8 o'clock with distilled water or deionized water again, the thick ester after the washing is sent into distillation tower and is carried out underpressure distillation (negative pressure, pressure 30～200mmHg post), remove unnecessary pure fraction, the thick ester after the processing passes through activated carbon (or carclazyte) adsorption bleaching again.By pressure filter sorbent material is separated with liquid ester, the gained liquid ester can be used as plastic plasticizer.
DMT in the raw material, DMI, DMO all can with C
4～C
20Alcohol generation transesterification reaction, particularly react with octanol (2-Ethylhexyl Alcohol), terephthalic acid two octanols (DOTP) that generated, m-phthalic acid two octanols (DOIP), phthalic acid two octanols (DOP), it all is the Plasticizer for plastics of excellent property, therefore the mixture with this three kinds of esters of this feedstock production is used as softening agent, has good plasticising performance equally; This product can be used for plastics such as polyvinyl chloride.
The present invention further sets forth by embodiment.
Embodiment 1:
(1) filtrate residue distillation: operation of equipment condition: packing tower, 50 of theoretical trays, reflux ratio is 2, periodical operation, negative pressure (pressure 100～200mmHg) distillations, raw material residual II I160g, must be less than 180 ℃ of fractions, 14.5 grams, greater than 240 ℃ of fractions, 20.0 grams, 180～240 ℃ of fractions 113.5 restrain.
(2) with the octanol reaction: get isomer (i.e. 180～240 ℃ of fractions) 98 grams, octanol 200 grams, catalyzer 1 gram, put into reactor, warming while stirring is when temperature of reactor is raised to 152 ℃, have methyl alcohol to steam, heat up gradually then, methyl alcohol is steamed continuously, after 90 minutes, reactor temperature rises to 200 ℃, has not had methyl alcohol and has distillated, and reaction finishes, get methyl alcohol 31.8 grams, reactant is thick ester 260 grams.
(3) thick ester aftertreatment: get thick ester 240 grams, add 30 gram 1.0%Na
2CO
3Solution stirred 60 minutes down at 70 ℃, and standing demix divides and removes the bottom waste lye, and washes with water then, to the washing water pH value be 7～8.Thick ester underpressure distillation after will washing again, pressure are 80mmHg (absolute pressure), and the still temperature is 118～200 ℃, to remove octanol.Through activated carbon adsorption, press filtration gets finished product 176 grams again.Product quality indicator is: ester content 99%, acid number 0.10, No. 30, color and luster (APHA), 216 ℃ of flash-points.
Embodiment 2:
(1) filtrate residue distillation: operation of equipment condition: packing tower, 80 of theoretical trays, reflux ratio is 2, periodical operation, negative pressure (pressure 100～200mmHg) distillations, raw material residual II I310g, must be less than 180 ℃ of fractions, 25.0 grams, greater than 240 ℃ of fractions, 48.0 grams, 180～240 ℃ of fractions 220.0 restrain.
(2) with the octanol reaction: get isomer (i.e. 180～240 ℃ of fractions) 200 grams, octanol 360 grams, catalyzer 1 gram, add in the reactor, warming while stirring is when temperature of reactor is raised to 160 ℃, have methyl alcohol to steam, heat up while react then, methyl alcohol is steamed continuously, after 80 minutes, reactor temperature rises to 220 ℃, has not had methyl alcohol and has distillated, and reaction finishes, get methyl alcohol 66.5 grams, reactant is thick ester 480 grams.
(3) thick ester aftertreatment: get thick ester 300 grams, add 40 gram 1.0%Na
2CO
3Solution stirred 60 minutes down at 70 ℃, and standing demix divides and removes the bottom waste lye, and washes with water then, to the washing water pH value be 7～8.Thick ester underpressure distillation after will washing again, pressure are 80mmHg (absolute pressure), and the still temperature is 110～200 ℃, to remove octanol.Through activated carbon adsorption, press filtration gets finished product 240 grams again.Product quality indicator is: ester content 99.2%, acid number 0.09, No. 35, color and luster (APHA), 220 ℃ of flash-points.
Embodiment 3:
(1) filtrate residue distillation: operation of equipment condition: packing tower, 50 of theoretical trays, reflux ratio is 2, periodical operation, negative pressure (pressure 100～200mmHg) distillations, raw material residual II I340g, must be less than 180 ℃ of fractions, 28.0 grams, greater than 240 ℃ of fractions, 58.0 grams, 180～240 ℃ of fractions 230.0 restrain.
(2) with positive tetradecyl alcohol reaction: get isomer (i.e. 180～240 ℃ of fractions) 170 grams, positive tetradecyl alcohol 500 grams, catalyzer 2 grams, put into reactor, warming while stirring is when temperature of reactor is raised to 179 ℃, have methyl alcohol to steam, heat up gradually then, methyl alcohol is steamed continuously, after 190 minutes, reactor temperature rises to 240 ℃, has not had methyl alcohol and has distillated, and reaction finishes, get methyl alcohol 63.4 grams, reactant is thick ester 560 grams.
(3) thick ester aftertreatment is the same.Product quality indicator is: ester content 99.4%, acid number 0.12, No. 30, color and luster (APHA), 227 ℃ of flash-points.
With the product of embodiment 1,2 join in the polyvinyl chloride performance and with the comparison of DOP:
Claims (3)
- In a kind of DMT treating process residue (III) utilize method, it is characterized in that comprising residue pre-treatment, transesterification reaction, thick three operations of ester aftertreatment:(1) residue pre-treatment: the DMT crystalline mother solution is gained raffinate III after distilling, further (absolute pressure 6～200mmHg) fractionation by distillation become＜180 ℃ of cuts by decompression again, 180～240 ℃ of cuts, three parts of＞240 ℃ of cuts, first part's (＜180 ℃ of cuts) returns the crystallization again of DMT production system, third part (＞240 ℃ of cuts) discards, and second section (180～240 ℃ of cuts) DMT isomer is as the raw material of next operation transesterification reaction;
- (2) transesterification reaction: the isomer raw material that last operation obtains adds in the transesterification reactor, and adds C in proportion 4Or C 5～C 20Alcohol (alcohol/isomer=1.0～2.0/1.0), under normal pressure, 140 ℃～240 ℃ of temperature are reaction down, reactor is provided with agitator, well heater, condenser, when treating the methyl alcohol quantity of distillate near the methyl alcohol theoretical amount, reaction terminating obtains thick ester; Catalyst for ester exchange reaction adopts acetate or titanic acid ester, and add-on is the isomery scale of construction (W) 0.1～1.0%;
- (3) thick ester is put into the conical vessel that a bottom is provided with opening, and adding concentration is 5～15% NaCO 3Solution, volume is 1～2 times of thick ester volume, temperature remains on 70～80 ℃, stirred 30～60 minutes, standing demix is isolated the waste lye of bottom, clean thick ester till water outlet PH=7～8 with distilled water or deionized water again, thick ester after the washing is sent into vacuum still again, and (pressure 30～200mmHg) is removed unnecessary pure cut, and the thick ester after distillation passes through activated carbon (or carclazyte) adsorption bleaching again, by pressure filter sorbent material (activated carbon or carclazyte) is separated with the liquid carboxylate.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 96104753 CN1163883A (en) | 1996-04-26 | 1996-04-26 | Utilization of residue in DMT refining process |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 96104753 CN1163883A (en) | 1996-04-26 | 1996-04-26 | Utilization of residue in DMT refining process |
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| Publication Number | Publication Date |
|---|---|
| CN1163883A true CN1163883A (en) | 1997-11-05 |
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ID=5118506
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 96104753 Pending CN1163883A (en) | 1996-04-26 | 1996-04-26 | Utilization of residue in DMT refining process |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111205182A (en) * | 2020-02-13 | 2020-05-29 | 厦门大学 | Method for preparing mixed plasticizer and environment-friendly plasticizer by using PTA residues |
-
1996
- 1996-04-26 CN CN 96104753 patent/CN1163883A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111205182A (en) * | 2020-02-13 | 2020-05-29 | 厦门大学 | Method for preparing mixed plasticizer and environment-friendly plasticizer by using PTA residues |
| CN111205182B (en) * | 2020-02-13 | 2020-10-27 | 厦门大学 | Method for preparing mixed plasticizer and environment-friendly plasticizer by using PTA residues |
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