CN109776315A - A method of environment-friendly plasticizer dibenzoic diglycol laurate is prepared by Action In The Liquid Phase Oxidation of Xylene residue - Google Patents

Abstract

The invention discloses a kind of methods that recycling Action In The Liquid Phase Oxidation of Xylene residue prepares environment-friendly plasticizer dibenzoic diglycol laurate.This method includes three oxidation, extraction and esterification characterization steps.1) it aoxidizes: the further oxidation processes of oxidant being added into Action In The Liquid Phase Oxidation of Xylene residue, material is sent into extraction cells after oxidation reaction.2) extract: the oxide flow from oxidation unit is mixed with water and oily phase extractant, then separates to obtain solid phase, water phase and oil phase material: oil phase material deesterify unit.3) be esterified: benzoated oil is mutually sent into esterifier with diethylene glycol (DEG), and benzoic acid components and diethylene glycol (DEG), which are gradually esterified, is converted to dibenzoic diglycol laurate；Thick DEDB product obtains environment-friendly plasticizer dibenzoic diglycol laurate product after alkali cleaning, washing and drying.The recycling of benzoic acid in Action In The Liquid Phase Oxidation of Xylene residue in conjunction with the preparation of DEDB, can effectively reduce Action In The Liquid Phase Oxidation of Xylene Slag recovering cost, while obtaining high-quality DEDB product by this method.

Description

It is a kind of that environment-friendly plasticizer dibenzoic diglycol laurate is prepared by Action In The Liquid Phase Oxidation of Xylene residue Method

Technical field

It is to existing recovery method the present invention relates to the method that a kind of resource utilization of Action In The Liquid Phase Oxidation of Xylene residue utilizes It improves, is reacted and separated and be prepared into environment-friendly plasticizer two with the material stream containing benzoic acid recycled by introducing diethylene glycol (DEG) Benzoic acid diethylene glycol (DEG) ester (DEDB).

Background technique

P-phthalic acid (PTA) and smart M-phthalic acid (PIA) are all important polyester monocase raw material, mainly adopt at present It is produced with the catalytic oxidation of dimethylbenzene (PX, MX), first passes through air oxidation and obtain thick phthalic acid, then hydrofinishing obtains To high purity extractive terephthalic acid (TPA) (PTA) and smart M-phthalic acid (PIA) product.In process of production, in order to control benzene diformazan The impurity concentration of acid, a part of circular response mother liquor, which can be extracted, carries out impurity and purification processing, after recovery of acetic acid and catalyst Solid waste is exactly Action In The Liquid Phase Oxidation of Xylene residue.The residue complicated components, main component include benzoic acid, terephthalic acid (TPA), Phthalic acid, phthalic acid, trimellitic acid, p -carboxybenzaldehyde, p-methylbenzoic acid etc., wherein benzoic acid composition may be up to 60wt% has very high recycling value.Currently, for oxidation residua benzoic acid components recycling mostly use dissolution, The separation methods such as crystallization, extraction and rectifying recycle to obtain benzoic acid.As CN01127075 disclose it is a kind of using dissolution, crystallization The method that benzoic acid in TA solid residue is recycled with rectifying, process energy consumption is high, and the rate of recovery is low, while also generating a large amount of waste water, Cost recovery is high.PTA oxidation residue recovery disclosed in CN201310410895.1 utilizes in method, first by residue in water and toluene Or extractive crystallization is carried out in the dual solvent system of dimethylbenzene, then solid phase, oil are mutually enriched with water phase three phase separation, benzoic acid In oily phase, benzoic acid components are obtained by oily phase rectifying is recyclable.Because benzoic acid fusing point is higher, easily occur during rectification under vacuum Equipment and line clogging produce difficult stablize.It is complicated equipped with solid product treatment process, including the equipment such as cooling, slice, packing, It is high to invest big energy consumption.Because of benzoic acid Odor stimulation, labor protection grade is high during practical application in industry, large labor intensity. CN201510429093.4, which is disclosed using methyl esterization, recycles terephthalic acid (TPA), M-phthalic acid and benzene in TA solid residue The method of formic acid, but the methyl benzoate product market demand recycled is small, as large-scale industrial application also needs to develop benzoic acid The subsequent transformation of methyl esters utilizes product.Thus, there is problem in existing Action In The Liquid Phase Oxidation of Xylene Slag recovering method, need to carry out skill Art is improved and product up-gradation.

Phthalic ester plasticizer is current most widely used plasticizer, because such plasticizer has environmental hormone With carcinogenesis risk, use scope is increasingly subject to limit.In comparison, dibenzoic diglycol laurate (DEDB) is a kind of environmental protection The plasticizer of type, toxicity is low, and has the characteristics that better compatibility, cold resistance, antistatic property, thermal stability, is expected to advise greatly Mould replaces existing phthalic ester plasticizer, has good market prospects.Currently, about environment-friendly plasticizer in industry It is catalyst that the preparation of dibenzoic diglycol laurate (DEDB), which mostly uses greatly the concentrated sulfuric acid, toluenesulfonic acid or aluminium oxide, and toluene is band Aqua, technique side reaction is serious, and coloured product is deep, the subsequent processes for needing decoloration etc. complicated, at present about the report of DEDB Road focuses mostly in the exploitation of effective catalyst.CN200810244443.X discloses a kind of DEDB preparation of no water entrainer (solvent) Method, using benzoic acid and diethylene glycol (DEG) as raw material, using the composite catalyst of titanate esters, active carbon and diatomite, catalyst passes through It is separated by filtration.CN201210294097.2 and CN201310608079.1 also uses the similar composite catalyzing containing titanate ester Agent.CN201310058116 then discloses a kind of composite catalyst using titanate esters, stannous oxide or Sold Stannous Chloride Catalyzes agent DEDB preparation method, can effectively reduce esterification reaction temperature, reduce side reaction, improve the quality of product. CN201110046217.2 discloses a kind of for synthesizing the SO4 of DEDB^2-/ZrO₂/SiO₂Solid acid catalyst was synthesized in DEDB Esterifying efficiency can be improved using the catalyst in journey, DEDB yield is up to 98.6%, and esterification yield is up to 99.5%, due to reaction and endless Entirely, the DEDB product of high-quality is such as obtained, claims that the processes such as the neutralization that can be saved, washing, decoloration can not be omitted in patent. CN201110243936.3 discloses a kind of ionic-liquid catalyst for esterification, and ionic-liquid catalyst can bring catalyst At high cost, the problems such as recycling is difficult.The report for carrying out optimization of process conditions using custom catalysts about DEDB preparation is quite a few, CN200810202125.7 uses Bronsted acid to carry out DEDB preparation for catalyst, uses saturated hydrocarbons for water entrainer, in benzoic acid/bis- Glycol mass ratio 1.9~2.0, under the conditions of 90-200 DEG C of reaction temperature, dibenzoic acid diethylene glycol (DEG) can be made in batch-type reaction 6-16h Ester product, conversion of benzoic acid reach 98%.CN201210193060.0 uses Anhydrous potassium carbonate for catalyst, with benzoic ether It is that raw material carries out ester exchange reaction preparation DEDB, while using methanol or ethyl alcohol for entrainer with diethylene glycol (DEG).Due to benzene feedstock first The more difficult acquisition of acid esters, while ester exchange reaction is slower, and further relates to the separating-purifying of alcohols, process is complicated, at high cost. CN201310701995.X then uses sodium bisulfate for catalyst, and benzoic acid and diethylene glycol (DEG) are raw material, needs after the completion of esterification Neutralized, washed, is layered, being decolourized and drying and other steps after obtain high-quality DEDB plasticizer.

In view of the market of DEDB maturation, the present invention is by the recycling of benzoic acid in Action In The Liquid Phase Oxidation of Xylene residue and the preparation knot of DEDB It closes, can effectively reduce Action In The Liquid Phase Oxidation of Xylene Slag recovering cost, while obtaining high-quality DEDB product.

Summary of the invention

The object of the present invention is to provide the methods that a kind of resource utilization of Action In The Liquid Phase Oxidation of Xylene residue utilizes, first by residue point From rich benzoated logistics is recycled to obtain, the benzoic acid material stream of recycling is then subjected to esterification with diglycol material and is made Environment-friendly plasticizer dibenzoic diglycol laurate (DEDB).Technology of the invention includes three oxidation, extraction, esterification steps:

1) it aoxidizes: the further oxidation processes of oxidant being added into Action In The Liquid Phase Oxidation of Xylene residue, material is sent into after oxidation reaction Extraction cells.

2) extract: oxide flow from oxidation unit is mixed with water and oil phase extractant, wherein Action In The Liquid Phase Oxidation of Xylene residue, The mass ratio of water and oily phase extractant is 1:(0.2~10): (0.5~20)；, then separate to obtain solid phase, water phase and oil phase material: Solid-phase material mainly contains M-phthalic acid and terephthalic acid (TPA)；Water phase material mainly contains cobalt, Mn catalyst etc., recycling catalysis It is discharged after agent；Oil containing benzoic acid mutually extracts material deesterify unit.

3) be esterified: benzoated oil is mutually and diethylene glycol (DEG) is with certain ratio feeding esterifier, benzoic acid components and two Glycol, which is gradually esterified, is converted to dibenzoic diglycol laurate (DEDB) and water, and formula (1) is shown in reaction；The water of generation is by the oily phase that vaporizes Extractant takes esterifier out of together, and the extractant of recycling is recycled back to extraction cells；Thick ester DEDB is by alkali cleaning, washing and does Environment-friendly plasticizer dibenzoic diglycol laurate (DEDB) product is obtained after dry.

Heretofore described Action In The Liquid Phase Oxidation of Xylene residue is primarily referred to as the preparation of paraxylene (PX) liquid phase catalytic oxidation to benzene Dioctyl phthalate or meta-xylene (MX) oxidation prepare the solid slag that mother liquor dedoping step generates in M-phthalic acid device.Such is residual Slag component is complicated, not only containing a large amount of benzoic acid (BA), M-phthalic acid (IPA), terephthalic acid (TPA) (TA), to methylbenzene first Acid (PT), m-methyl benzoic acid (IT), p formylbenzoic acid (4-CBA), formylbenzoate (3-CBA), O-phthalic Acid (OPA), trimellitic acid (TMA) component also contain acetic acid, water and metallic cobalt, Mn catalyst.Wherein benzoic acid content is no less than 20wt%.

Heretofore described 1) in oxidation step, Action In The Liquid Phase Oxidation of Xylene residue can be with oxidant oxygen-containing molecules gas or peroxide Oxidation reactor is fed together after changing aqueous solution of hydrogen mixing；It is preferred that use oxygen-containing gas of the oxygen concentration greater than 5.0% for oxidant, It can be air, pure oxygen or oxygen rich gas, preferably air.It is catalysis with Co, Mn that residue slurry is brought into oxidation reactor Agent, methyl, formoxyl and methylol groups on component phenyl ring are oxidized to corresponding carboxyl by oxygen molecule, such as by PT, 4-CBA It is further oxidized to as phthalic acid, key reaction formula is shown in formula (2)~(4).Meanwhile the water of by-product is taken out of instead in company with oxidized tail gas Answer device.

Heretofore described oxidizing reaction temperature range is 140~200 DEG C, and reaction pressure range is 0.2~2.0MPa, It is preferred that 160~180 DEG C, 0.5~1.0MPa；Stirred-tank reactor can be used, it is ensured that gas-liquid two-phase dispersion and oxygen in reactor Transmitting；The liquid phase residence time is 0.5~5 hour, preferably 1~3 hour in oxidation reactor.

If 1) oxidation step of the present invention is omitted or does not use, on the one hand PT, 4- due to containing in residue The amount of CBA is few, cannot obtain effective recycling, waste of resource；On the other hand, after the presence of these impurity also will seriously affect Continuous extraction and esterification recycling dibenzoic diglycol laurate (DEDB) product quality.Especially methyl benzoic acid be easy to by extraction with Benzoic acid enters oily phase together, and esterification enters dibenzoic diglycol laurate product together with diethylene glycol (DEG), influences dibenzoic acid two Glycol ester product quality.And oxidizing process is used, the impurity that can be difficult to these to recycle is completely converted into phthalic acid and its derivative Object is simultaneously enriched in solid phase extraction.

Heretofore described 2) in extraction step, oxidation residua logistics and water and oily phase extractant from oxidation step It mixes, at 50-200 DEG C, hybrid extraction 0.5~2 hour, wherein the mass ratio of oxidation residua, water and oily phase extractant is 1: (0.5~2): (1~4).

Heretofore described 2) in extraction step, in order to improve separative efficiency, while guaranteeing the purity of separated substance, The oil phase extractant is the mixture that one or more of toluene, benzene or dimethylbenzene arbitrarily match.

Heretofore described 2) in extraction step, solid phase, oil are obtained mutually and the object of water phase three phase separation by mutually separating Material, device for phase saparation is using combination one or more of in decanter, movable flow device, centrifuge and filter.Liquid-solid separation process The implementation of the solid-liquid separating equipments such as centrifuge, movable flow device known to this professional domain or filter can be used, liquid-liquid separation process can Implemented using oily water separating equipments such as well known decanter, movable flow devices.

Heretofore described 2) in extraction step, by the solid phase that mutually separates acquisition, oil mutually and in water phase, isophthalic diformazan Acid and terephthalic acid (TPA) be enriched in solid phase, benzoic acid is mainly enriched in oily phase, cobalt, manganese Metal ionic catalyst, acetic acid and Water-soluble aromatic carboxylic acid is enriched in water phase.

Heretofore described 2) in extraction step, by mutually separating the oil containing benzoic acid of acquisition, mutually extraction material is gone 3) esterif iotacation step.

Heretofore described 2) in extraction step, the solid phase by mutually separating acquisition is rich in M-phthalic acid and to benzene The mixture of dioctyl phthalate, by being recycled after washing drying.

Heretofore described 2) in extraction step, cobalt, manganese Metal ion are contained in the water phase by mutually separating acquisition, it can Using the methods of ion exchange resin absorption, oxalic acid precipitation, alkali precipitation separating and recovering cobalt, manganese Metal catalyst；It is enriched inclined benzene The water phase of three sour (TMA), phthalic acid (OPA), acetic acid etc. can separate a variety of fragrance by the method for crystallising such as cooling down, flashing Carboxylic acid, the water after purification, which also can return to, is used as extraction mashing water.

Heretofore described 3) in esterif iotacation step, the oil containing benzoic acid from 2) extraction step mutually extraction material and Diethylene glycol (DEG) is sent into multistage esterifier together and carries out esterification, and benzoic acid components and diethylene glycol (DEG), which are gradually esterified, is converted to hexichol Formic acid diethylene glycol (DEG) ester (DEDB) and water, reaction are shown in shown in formula (1).

Heretofore described 3) in esterif iotacation step, tower reactor, plural serial stage kettle can be selected in multistage esterifier The combination of formula reactor or both, reactor series are 2~10 grades.

Heretofore described 3) in esterif iotacation step, the temperature that multistage esterification uses is 150-250 DEG C, multistage esterification Reaction pressure 5.0kPa~normal pressure, multistage esterification total residence time are 1~6 hour.

Heretofore described 3) in esterif iotacation step, catalyst used by multistage esterification can be selected from titanate esters, The titaniums such as pink salt, antimony glycol, tin, antimony compound, preferred titanate ester catalyst.

Heretofore described 3) in esterif iotacation step, the water of generation takes esterification out of by the oily phase extractant vaporized together Device, the discharging of esterifier liquid phase are mainly high boiling DEDB crude product.

Heretofore described 3) in esterif iotacation step, the discharging of esterifier gas phase passes through condensing recovery extractant and generation Water, oily phase extractant returns to 2) extraction step, and, with recycling, water phase is used as waste water discharge system after passing through stripping.

Heretofore described 3) in esterif iotacation step, it may contain in the thick DEDB product of liquid phase by esterifier outlet The impurity such as the complete benzoic acid of a small amount of unreacted, related impurities can first pass through alkali cleaning and then pass through washing and remove, finally by dry Dry acquisition high-quality environment protective plasticizer dibenzoic diglycol laurate (DEDB) product.

The not specified technology of the present invention is the prior art.Dimethylbenzene can effectively be recycled using method of the invention Benzoic acid (BA), M-phthalic acid (IPA), terephthalic acid (TPA) (TA) and cobalt-manganese catalyst component in oxidation residua.The present invention By in Action In The Liquid Phase Oxidation of Xylene residue benzoic acid recycling in conjunction with the preparation of DEDB, can effectively reduce Action In The Liquid Phase Oxidation of Xylene Slag recovering at This, while obtaining high-quality DEDB product.The resource utilization that chemical waste residue is not only realized using the present invention meets circulation warp The requirement of Ji, and reduce the discharge of waste residue in phthalic acid production process, protect environment.

Detailed description of the invention

Fig. 1 is the present invention using esterification and extractant rectifying separate process general flow chart.

Fig. 2 is the process flow diagram that the present invention is coupled using extractant rectifying and esterification.

Fig. 3 is the process flow diagram of the embodiment of the present invention 5,6.

Fig. 4 is the process flow diagram of the embodiment of the present invention 7,8.

Specific embodiment

For a better understanding of the present invention, below with reference to the embodiment content that the present invention is furture elucidated, but it is of the invention Content is not limited solely to the following examples.

Embodiment 1

P xylene oxidation residue handled by the present embodiment is typical from p-phthalic acid (PTA) production process P xylene oxidation residue composition be shown in Table 1.

PTA oxidation residua airoxidation is carried out using the autoclave of 1.0L.Autoclave is furnished with electric heating With interior cooling oil coil, temperature uses PID control；Reaction kettle gaseous phase outlet is furnished with shut-off valve, condenser, counterbalance valve, condenser Middle condensate liquid is reflowable to reactor, and counterbalance valve can control reaction pressure；It is also equipped with charge flow rate simultaneously and tail oxygen concentration is online Detection system.It uses typical case's Action In The Liquid Phase Oxidation of Xylene residue shown in table 1 for raw material, which is measured using ICP and contains 1500ppm's The Mn of Co and 500ppm.It quantitatively weighs oxidation residua 500.0g and mixes addition autoclave with 100g water；In whipping process In be passed through nitrogen, pressurize and heat up；When pressure rises to 1.8MPa, and temperature reaches 200 DEG C, it is passed through air and carries out oxidation reaction； Stop being passed through air after reaction 1.0 hours, reaction was completed, cooling sampling, using liquid-phase chromatographic analysis each component concentration.

Using Agilent1100 high performance liquid chromatograph when analysis, it be furnished with DAD UV detector and quaternary pump, color Spectrum column is Diamonsil-C18 (250 × 4.6mm/5 μm) column, and mobile phase is the ternary gradient elution of acetonitrile, first alcohol and water, is washed De- gradient is as follows: 0~10min, acetonitrile is by 10% linear increment to 30%, and methanol is by 10% linear increment to 20%；10~ 20min, acetonitrile is by 30% linear increment to 50%, and methanol is by 20% linear increment to 35%.

Residue analysis Comparative result is listed in table 1 after oxidation.

1. p xylene oxidation residue of table forms (butt)

Table 1 the result shows that, 4-CBA and PT effectively can be converted to by terephthalic acid (TPA) and its derivative using oxidizing process.It adopts With oxidizing process, it on the one hand can remove PT, 4-CBA impurity contained in residue, reduce influence of these impurity to DEDB product quality, Reduce later separation cost；On the other hand effective recycling also has been carried out to these a small amount of impurity, has improved resource reclaim efficiency.

Embodiment 2.

Action In The Liquid Phase Oxidation of Xylene residue handled by the present embodiment is residual using aoxidizing after 1 the method oxidation processes of embodiment Slag mainly forms (butt) and is shown in Table 1.The present embodiment uses paraxylene to extract for extractant to the oxidation residua Take processing.It takes 100 grams of residues and 100 grams of water to be added in stirring and the 1000ml three-necked flask being condensed back, adds simultaneously Enter 200 grams of paraxylene extractants (mass ratio of residue, water and extractant maintains to be about 1:1:2 in ingredient), is subsequently placed in 80 Stirring and cooling water are opened in DEG C heating water bath, sealing.80 are warming up to residue, water, paraxylene mixture paste temperature ± After 1.0 DEG C, constant temperature is stirred 1 hour.Gained liquid/solid/liquid three-phase slurry filters at 25 DEG C of room temperature, and room temperature 25 is respectively adopted in filter cake The dosage of water and paraxylene washing at DEG C, water and paraxylene is 50 grams.Solid phase is weighed quantitatively after drying, takes solid Sample.After filtrate stratification, oily phase filtrate and water phase filtrate sample are taken respectively.Using high performance liquid chromatography to solid sample, Each product component in oily phase filtrate sample and water phase filtrate sample carries out quantitative analysis.Because water phase filtrate has in temperature-fall period Solid separation, water phase data error are larger.It analyzes respectively mutually mainly to form and is listed in table 2.

Each phase component analyzes result after 2. embodiment of table, 2 extraction processing

As seen from the results in Table 2, being extracted by PX+ water can be achieved efficiently separating for each component.TA and IPA can be rich in solid phase Collection；For benzoic acid efficiently concentrating in PX extraction oil phase, the BA purity of enrichment may be up to 92.5%.

Embodiment 3.

The extraction and separation the same manner as in Example 2 for carrying out oxidation residua, handled Action In The Liquid Phase Oxidation of Xylene residue is also using reality Apply oxidation residua after 1 the method oxidation processes of example, unlike use toluene for extractant, extraction temperature also controls 80 ± 1.0℃.As different from Example 2, the composition that the present embodiment uses are as follows: 150 grams of residues, 150 grams of water and 150.0 grams of first Benzene, ingredient quality are maintained 1:1:1.After extraction after stratification, oily phase filtrate and water phase filtrate sample are taken respectively.Take solid-like Product, oily phase filtrate sample and water phase filtrate sample, carry out quantitative analysis to each component respectively, are as a result listed in table 3.Wherein Toluene oil The composition of phase is as shown in table 4.

Each phase component analyzes result after 3. embodiment of table, 3 extraction processing

^aContaining the toluene of 65.51wt% in oily phase, the amount of toluene is not calculated in composition.

As seen from the results in Table 3, the efficiently concentrating of benzoic acid can also be realized using toluene.The result of comparative example 2 and 3 can Know, toluene and paraxylene are suitable extractants, and toluene is the enrichment that extractant is more advantageous to benzoic acid.

Embodiment 4.

The Toluene oil phase containing benzoic acid obtained using embodiment 3 is mixed with diethylene glycol (DEG) carries out esterification, Toluene oil Phase composition is as shown in table 4.It takes 287g to form Toluene oil as shown in table 4 mutually in 50ml three-necked flask, while putting into zeolite two Grain three-necked flask is furnished with condensing reflux system, opens stirring condensation.150 DEG C are slowly heated to, lime set, lime set upper oil phase are collected Reflux, the extraction of lime set lower layer liquid phase.Then diethylene glycol (DEG) 39.72g is added, while catalyst butyl titanate 1.0g is added, opens It is stirred and condenses, be slowly heated to 180 DEG C, be heated to reflux under state and carry out esterification.Refluxing toluene is to three-necked flask In, the moisture batch for reacting generation is released.In 180 DEG C or so lower reflux dewatering about 5h, until esterification terminates when no moisture separates, Then it is cooled to room temperature.Using the above-mentioned material of soda lye wash, it is then allowed to stand, liquid separation, gained oil phase drying to obtain is faint yellow, Transparent oily liquid product.Use the yield of high performance liquid chromatography measurement dibenzoic diglycol laurate product for 97.3wt%.

Embodiment 5.

The present embodiment uses toluene extraction and the process flow of double-column in series processing PTA oxidation residua to obtain high-purity Dibenzoic diglycol laurate product, detailed process flow chart are shown in attached drawing 3.The composition of residue handled by the present embodiment (butt) is shown in Shown in table 4, mutually reacts with diethylene glycol (DEG) using the oil after toluene extraction residue and generate dibenzoic diglycol laurate.

Table 4.PTA oxidation residua forms table

By the PTA residue and water by 1:1 mashing charging, benzoic acid is extracted using toluene, before filtering, Liquid liquid Separation etc. Three phase separation is realized in processing, obtains the raw material rich in benzoic acid, toluene and partial impurities.

Then raw material is sent into rectifying separation impurity, then obtains DEDB with diethylene glycol (DEG) esterification, which uses rectifying The mode of tower, esterification reaction tower cascade towers.Specifically, it will be sent into rectifying column by toluene oily phase raw material extracted, Rectification under vacuum under 80kPa, tower top discharging are mainly toluene, and tower bottom is higher boiling residue, and lateral line discharging is mainly benzoic acid, are sent into First block of plate of esterification column overhead, rectification under vacuum under normal pressure, diethylene glycol (DEG) mixing portion toluene is from second piece of plate charging (two of tower top Glycol: benzoic acid mole fraction is about 1:2), tower bottom obtains the dibenzoic diglycol laurate of higher degree.It is subsequent to pass through alkali It washes, wash, drying further purification dibenzoic diglycol laurate product.

The raw material of double-column in series technique and the critical component table of product are shown in Table 5, in which: TL indicates that toluene, DGM indicate benzene first Sour diethylene glycol (DEG) ester, stream stock 101 be with the raw material flow stock after toluene extraction residue, 201 diethylene glycol (DEG)s being added for esterification reaction tower and Toluene mixed flow stock, the 202 toluene stream stocks being added for esterification reaction tower tower bottom, 204 be esterification reaction tower bottom product stream stock (stream Stock number has marked in process flow chart attached drawing 3), the yield of product DEDB is 95.4%.

The crucial stream stock table of 5. embodiment of table 4

Embodiment 6.

The present embodiment use technique same as Example 5, the difference is that change through extraction process treated stream The crucial stream stock composition of the composition (consistent with the ingredient extracted of embodiment 3) of stock 101, the embodiment is shown in Table 6.

The crucial stream stock table of 6. embodiment of table 6

After the composition of feeding flow stock 101 for using the present embodiment instead, the yield of products obtained therefrom DEDB is 97.5%.

Embodiment 7.

The present embodiment uses toluene extraction and three tower cascade connected process treatment PTA oxidation residua to obtain rich in benzoic acid Raw material, wherein toluene extraction process is identical as embodiment 4,5, but subsequent obtains high-purity by the way of three tower cascade connected Dibenzoic diglycol laurate product, detailed process flow chart is shown in attached drawing 4.Residue handled by the present embodiment forms (butt) It is shown in Table 4.

It is obtained respectively from tower top using the same materials obtained with the extraction of the toluene of embodiment 4, then by two rectifying columns The toluene and benzoic acid of high-purity are finally sent into esterification reaction tower according to a certain ratio and both obtain DEDB.Particularly, raw material is first sent Enter piptonychia benzene column, the rectifying under 80kPa pressure, tower top discharging is mainly toluene, and de- benzoic acid tower is sent into tower bottom discharging, in normal pressure Lower rectifying, tower top discharging is mainly benzoic acid, and tower bottom is the residue contained a large amount of impurities；The tower top discharging of de- benzoic acid tower is sent Entering esterification reaction tower third block plate, diethylene glycol (DEG) feeds (diethylene glycol (DEG): benzoic acid mole fraction is about 1:2) from first block of plate of tower top, Atmospheric operation, tower bottom obtain the dibenzoic diglycol laurate of higher degree.It is subsequent further to be mentioned by alkali cleaning, washing, drying Pure dibenzoic diglycol laurate product.

The raw material of three tower cascade connected technique and the critical component table of product are shown in Table 7, and stream stock 101 is with after toluene extraction residue Raw material flow stock, 201 discharge for the top of the distillation column T2, and the 301 diethylene glycol (DEG) stream stocks being added for esterification reaction tower, 304 be esterification Tower bottom product stream stock (stream stock number has marked in process flow chart attached drawing 3), the yield of product DEDB is 97.7%.

The crucial stream stock table of 7. embodiment of table 7

Embodiment 8.

The present embodiment use technique same as Example 7, the difference is that change through extraction process treated stream The crucial stream stock composition of the composition (identical as 5 feed composition of embodiment) of stock 101, the embodiment is shown in Table 8.

The crucial stream stock table of 8. embodiment of table 8

After the composition of feeding flow stock 101 for using the present embodiment instead, the yield of products obtained therefrom DEDB is 97.9%.

Claims (10)

1. a kind of method for preparing environment-friendly plasticizer dibenzoic diglycol laurate by Action In The Liquid Phase Oxidation of Xylene residue, which is characterized in that packet Include following technique unit:

1) oxidation unit: the further oxidation processes of oxidant are added into Action In The Liquid Phase Oxidation of Xylene residue, material is sent into after oxidation reaction Extraction cells；

2) extraction cells: the oxide flow from oxidation unit is mixed with water and oily phase extractant, then separates to obtain solid phase, water phase And oil phase material, the oil phase material deesterify unit containing benzoic acid；

3) esterification unit: benzoated oil is mutually and diethylene glycol (DEG) is with certain ratio feeding esterifier, benzoic acid components and two Glycol is gradually esterified and is converted to dibenzoic diglycol laurate crude product；Crude product obtains environmental protection after alkali cleaning, washing and drying Plasticizer dibenzoic diglycol laurate product.

2. the method according to claim 1, wherein the Action In The Liquid Phase Oxidation of Xylene residue is to urge from dimethylbenzene Change the solid residue generated in mother liquor dedoping step when oxidation prepares phthalic acid；Wherein contain benzoic acid, M-phthalic acid, right One or more of phthalic acid, methyl benzoic acid, formylbenzoate, phthalic acid and trimellitic acid；Additionally Metallic cobalt, Mn catalyst, acetic acid and water can be contained, wherein benzoic acid content is no less than 20wt%.

3. the method according to claim 1, wherein oxidation unit 1) in, the oxidizing reaction temperature range It is 140~250 DEG C, reaction pressure range is 0.2~3.0Mpa, and the oxidant is oxygen-containing molecules gas, aquae hydrogenii dioxidi The combination of solution or both.

4. the method according to claim 1, wherein extraction cells 2) in, the oily phase extractant be toluene, The mixture that one or more of benzene or dimethylbenzene arbitrarily match；The wherein matter of oxidation residua, water and oily phase extractant Amount is than being 1:(0.5~2): (1~4)；The temperature of extraction is 50-200 DEG C, and the time is 0.5~2 hour；Device for phase saparation uses One or more of combination in decanter, movable flow device and filter.

5. the method according to claim 1, wherein esterification unit 3) in, the esterification is using multistage Esterifier, benzoic acid and diethylene glycol (DEG) in charging are esterified step by step generates dibenzoic diglycol laurate and water, while feeding Extraction phase gasify take the water that esterification generates out of system step by step, it is single that the extractant recycled after vapor condensation is recycled back to extraction Member is 2).

6. according to the method described in claim 5, it is characterized in that, used be multistage esterifier is plural serial stage kettle Formula reactor, reactor series are 2~10 grades.

7. according to the method described in claim 5, it is characterized in that, the temperature that uses of the esterification for 150-250 DEG C, Pressure 5.0kPa~normal pressure, total residence time are 1~6 hour.

8. according to the method described in claim 5, it is characterized in that, multistage esterifier is tower reactor, from tower anti- Answer the top of device into reaction mass, reaction while carries out distillation operation, and the dibenzoic acid two for obtaining higher degree from tower bottom is sweet Alcohol ester.

9. according to the method described in claim 5, it is characterized in that, catalyst used by esterification selected from titanium, tin or The compound of antimony.

10. according to the method described in claim 9, it is characterized in that, catalyst used by esterification selected from titanate esters, Pink salt or antimony glycol.