CN108484392A - The method that choline eutectic ionic liquid catalyzed alcoholysis polyethylene terephthalate prepares Di-2-ethylhexyl terephthalate - Google Patents

Abstract

The invention relates to a method for preparing diisooctyl terephthalate (DOTP) from polyethylene terephthalate (PET) catalyzed by a novel catalyst, which is characterized in that it uses choline deep eutectic ionic liquid As a catalyst for alcoholysis, when the catalyst is synthesized, choline chloride is used as a hydrogen bond donor, and metal salts are used as a hydrogen bond acceptor. In the reaction process, isooctanol is used as solvent, the molar ratio of raw material to solvent is 1:2.5～1:8, the reaction temperature is 145°C～185°C, normal pressure, the reaction time is 30min～180min, and the amount of catalyst used is the mass of raw material Carry out alcoholysis of PET under the condition of 0.5%～10%. The method has the advantages of simple catalyst preparation, low cost, mild reaction conditions, short reaction time, high efficiency, high PET conversion rate, high target product selectivity, and an environmentally friendly reaction process.

Description

Preparation of Polyethylene Terephthalate by Alcohol Decomposition Catalyzed by Choline Eutectic Ionic Liquid Method for diisooctyl terephthalate

technical field

The invention belongs to the technical field of green and clean catalysis, and relates to a method for preparing diisooctyl terephthalate by catalyzing alcohol decomposition of polyethylene terephthalate (PET) with a novel catalyst.

Background technique

Diisooctyl terephthalate (DOTP), also known as bis(2-ethylhexyl) terephthalate, is a new type of plasticizer developed in recent years and is used in polyvinyl chloride (PVC) plastics. A primary plasticizer with excellent performance, widely used. DOTP is used as a plasticizer with low toxicity and high safety. It has been recognized as a non-toxic plasticizer and can be used in medical PVC products and plastic toys.

So far, there are three main methods for industrially synthesizing DOTP: one is the direct esterification of terephthalic acid and isooctyl alcohol; the other is the transesterification of dimethyl terephthalate; the third is polyterephthalic acid Ethylene glycol ester waste alcoholysis method (PET method). In addition to these three methods, there is also a terephthaloyl chloride method on a theoretical level. When using the first two methods to prepare DOTP, the requirements for raw materials are relatively high, and the reaction process is relatively complicated, and the reaction cost is high, so the polyethylene terephthalate waste preparation method (PET method) is currently the most studied method. , because there will be a lot of waste in the production of polyester industry, recycling these wastes to prepare plasticizers can not only turn waste polyester into treasure, but also bring new profit growth points to enterprises and increase the benefits of enterprises. The conventional catalysts for this process are concentrated sulfuric acid, zinc chloride, tetrabutyl titanate, sodium hydroxide and solid acid. However, these catalysts have a series of problems such as catalyst instability, corrosion of equipment, slow reaction due to long catalyst activation time, and high reaction temperature.

Because ionic liquids have obvious green chemical properties, the application of ionic liquids to certain catalytic reactions can replace those traditional toxic and heavily polluting non-environmentally friendly catalysts. With the deepening of research on ionic liquids, researchers have found that when some solid organic molecules and specific ionic compounds are mixed in a certain proportion, a eutectic mixture that is liquid at room temperature can be obtained, which contains both ionic components , also contains a certain amount of organic molecules. This kind of deep eutectic ionic liquid not only exhibits similar physical and chemical properties to traditional ionic liquids, but also has the advantages of easy preparation, low price, convenient storage, and 100% atom utilization. Due to their own advantages, deep eutectic ionic liquids have attracted increasing interest in many research fields, and there are more and more studies on deep eutectic ionic liquids as cheap and safe solvents or catalysts for many catalytic processes. .

The eutectic catalyst synthesized by choline chloride and metal salt is used in the reaction of degrading PET to prepare DOTP. The catalyst shows high activity, and the reaction time can be reduced by 5 to 8 times compared with traditional catalysts, and the required temperature for the reaction There was also a marked decline. The two raw materials are combined by hydrogen bond or metal coordination and complexation. The high activity of the catalyst is mainly due to the synergistic effect formed by choline and metal ions, which can simultaneously attack the hydroxyl on the alcohol and the long chain of PET. The carbonyl group accelerates the breaking of the long chain and connects with octanol to synthesize DOTP. Compared with the traditional reaction process, the reaction process has the advantages of mild conditions, fast reaction rate, and environmental protection. It provides an efficient and feasible new method for recycling waste PET to prepare environmentally friendly plasticizer DOTP.

Contents of the invention

The present invention uses deep eutectic ionic liquid as a catalyst and isooctanol as a solvent to realize green energy saving, high efficiency, high conversion rate and high selectivity to prepare terephthalic acid by catalytic alcoholysis of PET under mild reaction conditions Diisooctyl (DOTP) process.

General reaction formula of the present invention is:

A method for preparing diisooctyl terephthalate by alcoholysis of polyethylene terephthalate with a deep eutectic ionic liquid catalyst synthesized from choline chloride and metal salts, characterized in that isooctanol is used as a solvent , a deep eutectic ionic liquid catalyst synthesized with choline chloride and a metal salt of zinc acetate, zinc chloride, zinc nitrate, zinc sulfate, manganese acetate, and copper nitrate for alcoholysis of polyethylene terephthalate Preparation of di-isooctyl terephthalate.

The raw material source of the degraded polyethylene terephthalate is one or a mixture of mineral water bottles, carbonated beverage bottles and tea beverage bottles or polyethylene terephthalate particles.

When using choline chloride and zinc acetate, zinc chloride, zinc nitrate, zinc sulfate, manganese acetate, copper nitrate as raw materials to synthesize eutectic ionic liquid, the molar ratio of choline chloride and metal salt is 1:0.1 ~1:2.

When using choline chloride, zinc acetate, zinc chloride, zinc nitrate, zinc sulfate, manganese acetate, and copper nitrate as raw materials to synthesize the eutectic ionic liquid, the reaction temperature is 50°C to 120°C, and the reaction time is 30min ~240min.

The dosage of the catalyst is 0.5%-10% of the mass of polyethylene terephthalate.

The molar ratio of raw material to solvent for preparing di-isooctyl terephthalate by using choline deep eutectic ionic liquid as a catalyst to degrade polyethylene terephthalate is 1:2.5-1:8.

The reaction temperature for preparing di-isooctyl terephthalate by using choline deep eutectic ionic liquid as a catalyst to degrade polyethylene terephthalate is 145° C. to 185° C.

The reaction time for preparing diisooctyl terephthalate by using choline deep eutectic ionic liquid as a catalyst to degrade polyethylene terephthalate is 30 minutes to 180 minutes.

After the reaction finishes, the degradation rate of PET and the selectivity of product are calculated by formula (1) (2) respectively:

Among them, A represents the initial mass of PET added, and B represents the mass of undegraded PET after the reaction.

specific implementation plan

The present invention is described with the following examples, but the present invention is not limited to the following examples, and all changes are included in the technical scope of the present invention without departing from the scope of the subject.

Example 1

Using PET granules as raw material, 5.0g PET raw material, 17.0g isooctyl alcohol and 0.25g choline deep eutectic ionic liquid catalyst were added successively in a 50ml three-necked round-bottomed flask. The raw materials for the synthesis catalyst were choline chloride and zinc acetate. The molar ratio is 1:2, and the synthesis conditions are 70°C, 120min. The reaction temperature was controlled at 175° C. under normal pressure, condensed and refluxed for 60 minutes, and then cooled to room temperature. Under these conditions, the degradation rate of PET is 100%, and the selectivity of di-isooctyl terephthalate (DOTP) is 78.2%.

Example 2

Using PET granules as raw material, 5.0g PET raw material, 17.0g isooctyl alcohol and 0.25g choline deep eutectic ionic liquid catalyst were added successively in a 50ml three-necked round-bottomed flask. The raw materials for the synthesis catalyst were choline chloride and zinc acetate. The molar ratio is 1:1.5, and the synthesis conditions are 70°C, 120min. The reaction temperature was controlled at 185° C. under normal pressure, condensed and refluxed for 60 minutes, and then cooled to room temperature. Under these conditions, the degradation rate of PET is 100%, and the selectivity of di-isooctyl terephthalate (DOTP) is 82.5%.

Example 3

Using PET granules as raw material, 5.0g PET raw material, 17.0g isooctyl alcohol and 0.25g choline deep eutectic ionic liquid catalyst were added successively in a 50ml three-necked round-bottomed flask. The raw materials for the synthesis catalyst were choline chloride and zinc acetate. The molar ratio is 1:0.25, and the synthesis conditions are 50°C, 240min. The reaction temperature was controlled at 185° C. under normal pressure, condensed and refluxed for 60 minutes, and then cooled to room temperature. Under these conditions, the degradation rate of PET is 99.2%, and the selectivity of di-isooctyl terephthalate (DOTP) is 79.4%.

Example 4

Using PET granules as raw material, 5.0g PET raw material, 17.0g isooctyl alcohol and 0.25g choline deep eutectic ionic liquid catalyst were added successively in a 50ml three-necked round-bottomed flask. The raw materials for the synthesis catalyst were choline chloride and zinc acetate. The molar ratio is 1:2, and the synthesis conditions are 90°C, 180min. The reaction temperature was controlled at 175° C. under normal pressure, condensed and refluxed for 60 minutes, and then cooled to room temperature. Under these conditions, the degradation rate of PET is 100%, and the selectivity of di-isooctyl terephthalate (DOTP) is 78.4%.

Example 5

Using PET granules as raw material, 5.0g PET raw material, 17.0g isooctyl alcohol and 0.25g choline deep eutectic ionic liquid catalyst were added successively in a 50ml three-necked round-bottomed flask. The raw materials for the synthesis catalyst were choline chloride and zinc acetate. The molar ratio is 1:0.25, and the synthesis conditions are 70°C, 120min. The reaction temperature was controlled at 175° C. under normal pressure, condensed and refluxed for 120 minutes, and then cooled to room temperature. Under these conditions, the degradation rate of PET is 100%, and the selectivity of di-isooctyl terephthalate (DOTP) is 75.3%.

Example 6

Using PET granules as raw material, 5.0g PET raw material, 17.0g isooctyl alcohol and 0.25g choline deep eutectic ionic liquid catalyst were added successively in a 50ml three-necked round-bottomed flask. The raw materials for the synthesis catalyst were choline chloride and zinc acetate. The molar ratio is 1:0.1, and the synthesis conditions are 70°C, 120min. The reaction temperature was controlled at 175° C. under normal pressure, condensed and refluxed for 120 minutes, and then cooled to room temperature. Under these conditions, the degradation rate of PET is 98.7%, and the selectivity of di-isooctyl terephthalate (DOTP) is 79.4%.

Example 7

Using PET granules as raw material, 5.0g PET raw material, 17.0g isooctyl alcohol and 0.25g choline deep eutectic ionic liquid catalyst were added successively in a 50ml three-necked round-bottomed flask. The raw materials for the synthesis catalyst were choline chloride and zinc acetate. The molar ratio is 1:1, and the synthesis conditions are 85°C, 120min. The reaction temperature was controlled at 155° C. under normal pressure, condensed and refluxed for 120 minutes, and then cooled to room temperature. Under these conditions, the degradation rate of PET is 88.3%, and the selectivity of di-isooctyl terephthalate (DOTP) is 93.4%.

Example 8

Using PET granules as raw material, 5.0g PET raw material, 17.0g isooctyl alcohol and 0.25g choline deep eutectic ionic liquid catalyst were added successively in a 50ml three-necked round-bottomed flask. The raw materials for the synthesis catalyst were choline chloride and zinc acetate. The molar ratio is 1:1, and the synthesis conditions are 100°C, 90min. The reaction temperature was controlled at 145° C. under normal pressure, condensed and refluxed for 180 minutes, and then cooled to room temperature. Under these conditions, the degradation rate of PET is 83.9%, and the selectivity of di-isooctyl terephthalate (DOTP) is 94.6%.

Example 9

Using PET granules as raw material, 5.0g PET raw material, 17.0g isooctyl alcohol and 0.25g choline deep eutectic ionic liquid catalyst were added successively in a 50ml three-necked round-bottomed flask. The raw materials for the synthesis catalyst were choline chloride and zinc acetate. The molar ratio is 1:1, and the synthesis conditions are 80°C, 120min. The reaction temperature was controlled at 185° C. under normal pressure, condensed and refluxed for 180 minutes, and then cooled to room temperature. Under these conditions, the degradation rate of PET is 100%, and the selectivity of di-isooctyl terephthalate (DOTP) is 84.5%.

Example 10

Using PET granules as raw material, 5.0g PET raw material, 17.0g isooctyl alcohol and 0.25g choline deep eutectic ionic liquid catalyst were added successively in a 50ml three-necked round-bottomed flask. The raw materials for the synthesis catalyst were choline chloride and zinc acetate. The molar ratio is 1:1, and the synthesis conditions are 120°C, 60min. The reaction temperature was controlled at 145° C. under normal pressure, condensed and refluxed for 180 minutes, and then cooled to room temperature. Under these conditions, the degradation rate of PET is 93.9%, and the selectivity of di-isooctyl terephthalate (DOTP) is 94.6%.

Example 11

Using PET particles as raw materials, 5.0g PET raw materials, 27.0g isooctyl alcohol and 0.25g choline-based eutectic ionic liquid catalyst were added successively in a 50ml three-necked round-bottomed flask. The raw materials for the synthesis catalyst were choline chloride and zinc acetate. The molar ratio is 1:1, and the synthesis conditions are 120°C, 30min. The reaction temperature was controlled at 155° C. under normal pressure, condensed and refluxed for 180 minutes, and then cooled to room temperature. Under these conditions, the degradation rate of PET is 95.9%, and the selectivity of di-isooctyl terephthalate (DOTP) is 95.7%.

Example 12

Using PET granules as raw material, 5.0g PET raw material, 12.0g isooctyl alcohol and 0.25g choline deep eutectic ionic liquid catalyst were added successively in a 50ml three-neck round bottom flask. The raw materials of the synthetic catalyst were choline chloride and zinc acetate, two The molar ratio is 1:2, and the synthesis conditions are 70°C, 120min. The reaction temperature was controlled at 145° C. under normal pressure, condensed and refluxed for 180 minutes, and then cooled to room temperature. Under these conditions, the degradation rate of PET is 97.9%, and the selectivity of di-isooctyl terephthalate (DOTP) is 94.4%.

Example 13

Using PET particles as raw materials, 5.0g PET raw materials, 17.0g isooctyl alcohol and 0.25g choline-based eutectic ionic liquid catalyst were successively added in a 50ml three-necked round-bottomed flask. The raw materials for the synthesis catalyst were choline chloride and copper nitrate. The molar ratio is 1:1, and the synthesis conditions are 70°C, 120min. The reaction temperature was controlled at 185° C. under normal pressure, condensed and refluxed for 120 minutes and then cooled to room temperature. Under these conditions, the degradation rate of PET is 100%, and the selectivity of di-isooctyl terephthalate (DOTP) is 78.4%.

Example 14

Using PET granules as raw material, 5.0g PET raw material, 17.0g isooctyl alcohol and 0.25g choline-based eutectic ionic liquid catalyst were added successively in a 50ml three-necked round-bottomed flask. The raw materials for the synthesis catalyst were choline chloride and manganese acetate, two The molar ratio is 1:1, and the synthesis conditions are 70°C, 120min. The reaction temperature was controlled at 185° C. under normal pressure, condensed and refluxed for 120 minutes and then cooled to room temperature. Under these conditions, the degradation rate of PET is 100%, and the selectivity of di-isooctyl terephthalate (DOTP) is 79.2%.

Example 15

Using PET granules as raw material, 5.0g PET raw material, 17.0g isooctyl alcohol and 0.25g choline deep eutectic ionic liquid catalyst were added successively in a 50ml three-neck round bottom flask. The raw materials for the synthesis catalyst were choline chloride and zinc sulfate. The molar ratio is 1:1, and the synthesis conditions are 70°C, 120min. The reaction temperature was controlled at 185° C. under normal pressure, condensed and refluxed for 120 minutes and then cooled to room temperature. Under these conditions, the degradation rate of PET is 100%, and the selectivity of di-isooctyl terephthalate (DOTP) is 78.9%.

Example 16

Using PET granules as raw material, 5.0g PET raw material, 17.0g isooctyl alcohol and 0.5g choline deep eutectic ionic liquid catalyst were added successively in a 50ml three-neck round bottom flask. The raw materials for the synthesis catalyst were choline chloride and zinc acetate. The molar ratio is 1:1, and the synthesis conditions are 60° C., 180 min. The reaction temperature was controlled at 175° C. under normal pressure, condensed and refluxed for 30 minutes, and then cooled to room temperature. Under these conditions, the degradation rate of PET is 97.5%, and the selectivity of di-isooctyl terephthalate (DOTP) is 84.7%.

Example 17

Using PET granules as raw material, 5.0g PET raw material, 17.0g isooctyl alcohol and 0.25g choline deep eutectic ionic liquid catalyst were added successively in a 50ml three-neck round bottom flask, and the raw materials of the synthetic catalyst were choline chloride and zinc chloride, The molar ratio of the two is 1:1, and the synthesis conditions are 70°C, 120min. The reaction temperature was controlled at 185° C. under normal pressure, condensed and refluxed for 120 minutes and then cooled to room temperature. Under these conditions, the degradation rate of PET is 100%, and the selectivity of di-isooctyl terephthalate (DOTP) is 82.8%.

Example 18

With the Sprite bottle flakes with a side length of 0.5cm × 0.5cm as the PET raw material, 5.0g PET raw material, 17.0g isooctyl alcohol and 0.25g choline deep eutectic ionic liquid catalyst were added successively in a 50ml three-neck round bottom flask to synthesize the catalyst. The raw materials are choline chloride and zinc chloride, the molar ratio of the two is 1:1, and the synthesis conditions are 80°C, 120min. The reaction temperature was controlled at 185° C. under normal pressure, condensed and refluxed for 120 minutes, and then cooled to room temperature. Under these conditions, the degradation rate of PET is 100%, and the selectivity of di-isooctyl terephthalate (DOTP) is 80.6%.

Example 19

With the side length of 0.5cm × 0.5cm mineral water bottle flakes as PET raw materials, 5.0g PET raw materials, 17.0g isooctyl alcohol and 0.25g choline deep eutectic ionic liquid catalyst were added successively in a 50ml three-neck round bottom flask, and the catalyst was synthesized. The raw materials are choline chloride and zinc nitrate, the molar ratio of the two is 1:1, and the synthesis conditions are 70°C, 120min. The reaction temperature was controlled at 185° C. under normal pressure, condensed and refluxed for 120 minutes, and then cooled to room temperature. Under these conditions, the degradation rate of PET is 100%, and the selectivity of di-isooctyl terephthalate (DOTP) is 79.4%.

Example 20

Using PET granules as raw material, 5.0g PET raw material, 17.0g isooctyl alcohol and 0.5g choline deep eutectic ionic liquid catalyst were added successively in a 50ml three-neck round bottom flask. The raw materials for the synthesis catalyst were choline chloride and zinc acetate. The molar ratio is 1:1, and the synthesis conditions are 70°C, 120min. The reaction temperature was controlled at 185° C. under normal pressure, condensed and refluxed for 60 minutes, and then cooled to room temperature. Under these conditions, the degradation rate of PET is 100%, and the selectivity of di-isooctyl terephthalate (DOTP) is 83.5%.

Example 21

Using PET granules as raw material, 5.0g PET raw material, 8.5g isooctyl alcohol and 0.25g choline deep eutectic ionic liquid catalyst were added successively in a 50ml three-neck round bottom flask. The raw materials of the synthetic catalyst were choline chloride and zinc acetate. The molar ratio is 1:2, and the synthesis conditions are 70°C, 120min. The reaction temperature was controlled at 185° C. under normal pressure, condensed and refluxed for 60 minutes, and then cooled to room temperature. Under these conditions, the degradation rate of PET is 97.5%, and the selectivity of di-isooctyl terephthalate (DOTP) is 74.4%.

Example 22

Using PET granules as raw material, 5.0g PET raw material, 17.0g isooctyl alcohol and 0.025g choline-based eutectic ionic liquid catalyst were added successively in a 50ml three-necked round-bottomed flask. The raw materials for the synthesis catalyst were choline chloride and zinc acetate. The molar ratio is 1:2, and the synthesis conditions are 70°C, 120min. The reaction temperature was controlled at 185° C. under normal pressure, condensed and refluxed for 120 minutes, and then cooled to room temperature. Under these conditions, the degradation rate of PET is 99.5%, and the selectivity of di-isooctyl terephthalate (DOTP) is 77.6%.

Claims (7)

1. take choline chloride and metal salt as the method that the eutectic ionic liquid catalyst alcoholysis polyethylene terephthalate (PET) of raw material synthesis diisooctyl terephthalate (DOTP) is prepared, with Isooctyl alcohol is used as solvent, catalyst and polyethylene terephthalate for mixed reaction degradation. It is characterized in that choline chloride and metal salts: zinc acetate, zinc chloride, zinc nitrate, zinc sulfate, manganese acetate and copper nitrate are used as raw materials when preparing the catalyst. 2. catalyst according to claim 1 is characterized in that choline chloride and metal salt: the mol ratio of zinc acetate, zinc chloride, zinc nitrate, zinc sulfate, manganese acetate, copper nitrate is 1:0.1～1: 2. 3. The method for preparing the catalyst according to claim 1, characterized in that the reaction temperature is 50°C to 120°C and the reaction time is 30min to 240min when preparing the catalyst. 4. The method according to claim 1, characterized in that the catalyst consumption is 0.5% to 10% of the polyethylene terephthalate raw material quality. 5. The method according to claim 1, characterized in that the reaction temperature is 145°C to 185°C. 6. The method according to claim 1, characterized in that the molar ratio of raw material to solvent is 1:2.5 to 1:8. 7. The method according to claim 1, characterized in that the reaction time is 30min to 180min.