JP2008069130A - Process for preparing dry 3,9-bis(1,1-dimethyl-2-hydroxyethyl)-2,4,8,10-tetraoxaspiro[5,5]undecane powder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a process for preparing a dry 3,9-bis(1,1-dimethyl-2-hydroxyethyl)-2,4,8,10-tetraoxaspiro[5,5]undecane powder which can be stably operated. <P>SOLUTION: The process for preparing a dry 3,9-bis(1,1-dimethyl-2-hydroxyethyl)-2,4,8,10-tetraoxaspiro[5,5]undecane powder by indirectly heating a 3,9-bis(1,1-dimethyl-2-hydroxyethyl)-2,4,8,10-tetraoxaspiro[5,5]undecane powder wet with a solvent is a method of drying a wet 3,9-bis(1,1-dimethyl-2-hydroxyethyl)-2,4,8,10-tetraoxaspiro[5,5]undecane powder comprising passing a heating medium in the temperature range of the boiling point (°C) of the solvent to 190°C through a heating zone with the use of a drying machine which has a specific section and meets specific conditions. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to dry 3,9-bis (1,1-dimethyl-2-hydroxyethyl) -2,4,8,10-tetraoxaspiro [5,5] undecane (abbreviated as spiroglycol or SPG) powder. The present invention relates to a method for manufacturing a body.

Conventionally, when manufacturing dry SPG powder, an inlet for SPG powder moistened with a solvent, an outlet for dry SPG powder, an agitating blade rotating around the shaft, and a jacket on the outer wall of the dryer Was heated indirectly through the heating medium in the jacket (see Patent Document 1).

However, when the powder is kneaded by the stirring blade, adhesion occurs on the stirring blade and the like, and it is necessary to stop the apparatus in order to remove the adhesion.
JP 2003-55383

  The object of the present invention is to solve the above problems and to provide a method for producing dry SPG powder that can be stably operated.

  As a result of diligent investigations to solve the above problems, using a dryer having one or more heating parts inside, by rotating the heating part, 3,9-bis ( 1,1-dimethyl-2-hydroxyethyl) -2,4,8,10-tetraoxaspiro [5,5] undecane powder is stabilized by stirring and / or transporting from the inlet to the outlet The present invention has been completed.

That is, the present invention indirectly relates to a 3,9-bis (1,1-dimethyl-2-hydroxyethyl) -2,4,8,10-tetraoxaspiro [5,5] undecane powder wetted with a solvent. To dry 3,9-bis (1,1-dimethyl-2-hydroxyethyl) -2,4,8,10-tetraoxaspiro [5,5] undecane powder, (1) to (3) and satisfying the condition (4), a heating medium having a temperature range from the boiling point of the solvent (° C.) to 190 ° C. is passed through the heating section. The present invention relates to a method for drying 3,9-bis (1,1-dimethyl-2-hydroxyethyl) -2,4,8,10-tetraoxaspiro [5,5] undecane powder.
(1) Input port of 3,9-bis (1,1-dimethyl-2-hydroxyethyl) -2,4,8,10-tetraoxaspiro [5,5] undecane powder wetted with solvent (2 ) Dry 3,9-bis (1,1-dimethyl-2-hydroxyethyl) -2,4,8,10-tetraoxaspiro [5,5] undecane powder outlet (3) Inside the dryer Heating part through which heating medium is located (4) 3,9-bis (1,1-dimethyl-2-hydroxyethyl) -2,4,8, wet with solvent by rotating the heating part 10-tetraoxaspiro [5,5] undecane powder is stirred and / or transported from the inlet to the outlet

  According to the present invention, scaling formed inside the dryer is suppressed, and there is no adhesion on the stirring blade and the like, and a dry SPG powder can be stably and efficiently produced.

Hereinafter, the present invention will be described in detail.
The present invention is a method for producing a dry SPG powder by indirectly heating an SPG powder wetted with a solvent. The SPG powder wetted with a solvent, for example, combines hydroxypivalaldehyde and pentaerythritol with an acid. Synthesized by acetalization reaction in an aqueous solution under a catalyst, neutralized with an alkali, and then obtained through filtration and washing with spiroglycol crystals precipitated during the reaction (see JP-A-59-148776) . It can also be obtained by recrystallizing spiroglycol with alcohol and filtering and washing the crystals (Japanese Patent Laid-Open No. 2000-7678). Spiroglycol used for drying is wetted in the range of 5 to 40% by weight.

The dryer used in the present invention has the following (1) to (3).
(1) Input port for SPG powder moistened with solvent (2) Discharge port for dried SPG powder (3) Heating unit for passing a heating medium located inside the dryer Preferred dryer used in the present invention For example, as shown in FIG. 1 or FIG. 2, it has a heating part 4 for passing a heating medium located inside the dryer outer cylinder part 1, and an inlet for wet SPG powder. As for 2, what is provided in the side surface or upper part of a dryer is mentioned. Moreover, it is preferable that the discharge port 3 for the dry SPG powder is provided at the lower part of the dryer.
The shape of the heating section through which the heating medium is passed is tubular, prismatic, plate-like, disk-like, etc., and wings, plates, pins, etc. may be provided here.

The dryer used in the present invention satisfies the condition (4).
(4) By rotating the heating unit, the SPG powder wet with the solvent is stirred and / or transported from the inlet to the outlet. The SPG powder is stirred and / or transported from the inlet to the outlet. As the means, the heating unit is rotated. At this time, it is possible to provide pins and plates on the inner wall of the dryer so that the SPG powder is sufficiently mixed.
The rotation speed of the heating part is determined by the peripheral speed of the part where the heating part comes into contact with the wet SPG powder. Usually, the peripheral speed of the part where the heating part comes into contact with the wet SPG powder is 20 to 60 m / min, preferably 30 to 50 m / min.

  The dryer used in the present invention may have a condenser 6 that condenses a solvent such as water, hydrophilic and / or hydrophobic organic solvent evaporated from the SPG powder wet during drying, You may have the exhaust port 5 and the vacuum pump which exhaust the solvent vapor | steam which is not condensed with a condenser. Further, when the SPG powder is entrained in the solvent vapor, an SPG powder collection device such as a scrubber or a cyclone may be provided at the exhaust port. At this time, if necessary, the piping to the collecting device can be kept warm by steam tracing or the like so that the exhaust gas does not concentrate.

  In order to increase the efficiency of drying, or as an auxiliary role for the flow of the powder, gas may be passed or circulated in the dryer. The gas is circulated by a blower 7 as shown in FIG. Examples of the gas to be ventilated or circulated include air, nitrogen, helium, argon, and carbon dioxide. Nitrogen is particularly preferable from the viewpoint of physical properties of the dry SPG powder and availability of the gas.

  The inside of the dryer may be depressurized during drying. The pressure is not particularly limited, but when an organic solvent is included in the wet powder, it is preferable that the volatilized solvent be a pressure that can be sufficiently recovered by a solvent recovery device such as a condenser.

  In the present invention, the temperature of the heating medium to be passed to the heating unit is equal to or higher than the boiling point of the solvent contained in the wet powder charged into the inlet at the operating pressure of the dryer and less than the melting point of the dry SPG, preferably the boiling point of the solvent. + 15 ° C or higher and 190 ° C or lower. Examples of the heating medium include water, a liquid such as silicone oil, and a gas such as high-pressure steam. Among them, high-pressure steam is preferably used. The pressure and temperature of the high-pressure steam are, for example, about 120 ° C. at 0.2 MPa, about 150 ° C. at 0.5 MPa, and about 190 ° C. at 1.3 MPa.

The boiling point of the solvent in the present invention is the boiling point (° C.) of the solvent having the highest boiling point among the plurality of solvents at the operating pressure of the dryer, and has the azeotropic composition. When wetted with a plurality of solvents, the boiling point of the solvent having the highest boiling point among the plurality of solvents is compared with the azeotropic point of the plurality of solvents, and the higher temperature is defined as the boiling point (° C.) of the solvent.
For example, when the dryer is operated under atmospheric pressure when it is moistened with methanol and water, it does not have an azeotropic composition, so the boiling point of water is 100 ° C. (under atmospheric pressure), which is a boiling point higher than that of methanol. ) Is the boiling point. When wetted with toluene and water, these solvents have an azeotropic composition (azeotropic boiling point is 85 ° C under atmospheric pressure), and boiling points of toluene and water are 110 ° C and 100 ° C (under atmospheric pressure), respectively. Therefore, the boiling point is 110 ° C., which is the highest temperature among these.
When the inside of the dryer is depressurized during drying, the boiling point of the solvent under the reduced pressure is 190 ° C. or higher, and preferably the boiling point of the solvent under the reduced pressure is 15 ° C. or higher and 190 ° C. or lower.

In order to prevent the condensation of the solvent, it is preferable to keep the outer wall surface of the dryer at a temperature equal to or higher than the boiling point of the solvent with a heat insulating material or the like. Depending on the boiling point of the solvent, the ease of condensation, etc., it is possible to provide a heat retaining device through which a heat retaining medium such as steam trace can be passed, an electric heater or the like.
According to the method for producing dry SPG of the present invention, dry SPG having a solvent content of 0.5% by weight or less, preferably 0.2% by weight or less, particularly preferably 0.1% by weight or less can be produced.

  Next, the present invention will be described more specifically. However, the present invention is not limited to this.

<Method of synthesizing SPG powder wet with water>
<Synthesis of HPA>
While stirring 595 kg of isobutyraldehyde (hereinafter referred to as IBAL) and 657 kg of 37 wt% formalin under a nitrogen stream at 40 ° C., 33 kg of triethylamine (hereinafter referred to as TEA) was added over 5 minutes. At the end of the TEA addition, the reaction temperature reached 65 ° C. From here, the temperature of the reaction solution was gradually increased, and reached 90 ° C. after 30 minutes. The reaction was continued at 90 ° C. for 5 minutes, and then cooled to 60 ° C. by external cooling to stop the reaction.
Subsequently, unreacted IBAL, TEA, methanol and other low boiling fractions were distilled off at 60 to 70 ° C. and a pressure of 53 kPa. As a result of analyzing the composition of the reaction product liquid (hereinafter referred to as crude HPA) after distilling off this low boiling fraction using GC, HPA was 62.4% by weight, IBAL 0.26% by weight, formaldehyde 2.4% by weight, TEA 0.31 wt%, neopentyl glycol 0.64 wt%, hydroxypivalic acid neopentyl glycol monoester 2.0 wt%, isobutyric acid neopentyl glycol monoester 0.18 wt% and water 28.5 wt%. It was.
<SPG synthesis reaction>
49 kg of PE was dissolved in 600 kg of water, and 5 kg of 35 wt% hydrochloric acid was added. 147 kg of the crude HPA obtained above was added dropwise over 3.5 hours. At this time, the pH value of the reaction solution before the start of the reaction was 1.5, and the reaction temperature was 90 ° C. After completion of dropping, the mixture was aged for 3 hours at 90 ° C. The SPG concentration of the reaction slurry at the end of aging was 15.0% by weight. After the completion of aging, the reaction solution was separated into solid and liquid and washed with water to obtain 97 kg of SPG powder (water content 15% by weight) wetted with water.

Using the dryer shown in FIG. 1, the SPG powder moistened with 15% by weight of water was dried under the following conditions.
・ Input rate of wet SPG powder (input amount / hour, surface area of heating part): 8 kg / h · m ²
・ Pressure: Normal pressure (atmospheric pressure)
・ Heating medium: Heated steam (140 ℃, 0.4MPa)
・ Peripheral speed of the part where the heated part comes into contact with the wet SPG powder: 42 m / min
As a result of drying the SPG powder wetted under the above conditions, scaling was suppressed and a dry SPG having a moisture content of 0.1 wt% or less could be obtained. The yield of SPG with respect to the charged PE was 75 mol%, and analysis using GC revealed that the purity of the crystals was 99.2 wt%.

Schematic of the dryer used in the examples of the present invention Schematic of example dryer

Explanation of symbols

1: Dryer outer cylinder part 2: Powder input port 3: Powder discharge port 4: Heating unit 5: Exhaust port
6: Condenser 7: Blower

Claims (5)

Drying by indirectly heating 3,9-bis (1,1-dimethyl-2-hydroxyethyl) -2,4,8,10-tetraoxaspiro [5,5] undecane powder wet with solvent 3 , 9-bis (1,1-dimethyl-2-hydroxyethyl) -2,4,8,10-tetraoxaspiro [5,5] undecane powder comprising the following (1) to Dry 3,9-bis characterized by using a dryer having (3) and satisfying condition (4), and passing a heating medium in the temperature range of the boiling point (° C.) to 190 ° C. of the solvent through the heating section. A method for producing (1,1-dimethyl-2-hydroxyethyl) -2,4,8,10-tetraoxaspiro [5,5] undecane powder.
(1) Input port of 3,9-bis (1,1-dimethyl-2-hydroxyethyl) -2,4,8,10-tetraoxaspiro [5,5] undecane powder wetted with solvent (2 ) Dry 3,9-bis (1,1-dimethyl-2-hydroxyethyl) -2,4,8,10-tetraoxaspiro [5,5] undecane powder outlet (3) Inside the dryer Heating part through which heating medium is located (4) 3,9-bis (1,1-dimethyl-2-hydroxyethyl) -2,4,8, wet with solvent by rotating the heating part 10-tetraoxaspiro [5,5] undecane powder is stirred and / or transported from the inlet to the outlet The process according to claim 1, wherein the heating medium is at a temperature higher by 15 ° C or more than the boiling point of the solvent. The manufacturing method according to claim 1, wherein the drying is performed while aerating or circulating an air stream. The manufacturing method in any one of Claims 1-3 which keeps the outer wall surface of a dryer above the boiling point of a solvent. The manufacturing method in any one of Claims 1-4 dried under reduced pressure.

Images