IE910562A1 - Process for the synthesis of (methylbenzyl)xylene oligomers¹and their application as a dielectric - Google Patents
Process for the synthesis of (methylbenzyl)xylene oligomers¹and their application as a dielectricInfo
- Publication number
- IE910562A1 IE910562A1 IE056291A IE56291A IE910562A1 IE 910562 A1 IE910562 A1 IE 910562A1 IE 056291 A IE056291 A IE 056291A IE 56291 A IE56291 A IE 56291A IE 910562 A1 IE910562 A1 IE 910562A1
- Authority
- IE
- Ireland
- Prior art keywords
- xylene
- methylbenzyl
- oligomers
- oligomer
- mixture
- Prior art date
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
- H01B3/00—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties
- H01B3/18—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances
- H01B3/20—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances liquids, e.g. oils
- H01B3/22—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances liquids, e.g. oils hydrocarbons
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C15/00—Cyclic hydrocarbons containing only six-membered aromatic rings as cyclic parts
- C07C15/12—Polycyclic non-condensed hydrocarbons
- C07C15/16—Polycyclic non-condensed hydrocarbons containing at least two phenyl groups linked by one single acyclic carbon atom
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C2/00—Preparation of hydrocarbons from hydrocarbons containing a smaller number of carbon atoms
- C07C2/86—Preparation of hydrocarbons from hydrocarbons containing a smaller number of carbon atoms by condensation between a hydrocarbon and a non-hydrocarbon
- C07C2/861—Preparation of hydrocarbons from hydrocarbons containing a smaller number of carbon atoms by condensation between a hydrocarbon and a non-hydrocarbon the non-hydrocarbon contains only halogen as hetero-atoms
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C2527/00—Catalysts comprising the elements or compounds of halogens, sulfur, selenium, tellurium, phosphorus or nitrogen; Catalysts comprising carbon compounds
- C07C2527/06—Halogens; Compounds thereof
- C07C2527/128—Compounds comprising a halogen and an iron group metal or a platinum group metal
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/50—Improvements relating to the production of bulk chemicals
- Y02P20/52—Improvements relating to the production of bulk chemicals using catalysts, e.g. selective catalysts
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Physics & Mathematics (AREA)
- Spectroscopy & Molecular Physics (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)
- Organic Insulating Materials (AREA)
Abstract
Process for the synthesis of (methylbenzyl)xylene oligomers. The invention also relates to a new dielectric liquid consisting of a mixture of (methylbenzyl)xylene and di(methylbenzyl)xylene.
Description
The present invention relates to a process for the synthesis of (methylbenzyl)xylene oligomers.
In EP-A-299,867 there are described polyarylalkane oligomers which can be prepared by chlorination of toluene or xylene, followed by a condensation with xylene using a Friedel and Crafts reaction. We have found that some of these products are dielectrics.
The present invention therefore provides the 10 use as a dielectric fluid of the following oligomers A or B or of the mixture of A and B.
Oligomer A, which is called (methylbenzyl)xylene oligomer, is an isomer or a mixture of isomers of formula:
in which nx and n2 = 0, 1 or 2, such that nx + n2 is less than or equal to 3.
Oligomer B is an isomer or a mixture of isomers of formula:
in which n'lf n'’^ and n4 have the value 0, 1 or 2, n'2, η·'2, n3r n'3 and n5 have the value 0 or 1 such that n’x + n'^ + n'2 + n”2 + n3 + n'3 + n4 + n5, which is denoted by Sn, is less than or equal to 2.
Among the (methylbenzyl)xylene oligomers A, the name (methylbenzyl)xylene is given to those in which ni + n2 = 0 and that of di(methylbenzyl)xylene to those in which nx + n2 1.
These oligomers can be employed as dielectrics 10 in, say, transformers, capacitors, or even in electrical cables. For dielectric applications it is recommended to purify the products, for example with the aid of decolorising earths or adsorbents and to stabilise them by the addition of epoxides. These purification treatments and the various additives are known per se. The oligomers A or B or A and B can be mixed with other dielectric fluids.
The present invention also provides a mixture of oligomers A containing products in which nx + n2 = 0 and also those in which nx + n2 = 1, that is to say (methylbenzyl)xylene and di(methylbenzyl)xylene.
We have unexpectedly found that, although (methylbenzyl)xylene prepared from ortho-xylene crystallises at -40eC and that di(methylbenzyl)xylene prepared from ortho-xylene is solid at room temperature, their mixture crystallises at a lower temperature. In particular, a mixture containing 5 to 30 parts of di(methylbenzyl)xylene and, respectively, 95 to 70 parts of (methylbenzyl)xylene crystallises between -50 and -60°C. It is also possible for the above mixture of oligomers A, that is to say the mixture of oligomers such that nx + n2 = 0 and nx + n2 = 1, to contain oligomers B.
By way of examples, mixtures such that:
nl + n2 = 0 85 85 80 80 ηχ + n2 = 1 15 10 20 20 20 sn = o 2 4 2 4
xhibit crystallisation below -40°C.
Oligomer A can be prepared, for example, by condensing methylbenzyl chloride with xylene. Oligomer B can 25 be prepared by condensing xylene dichloride CH2C1-C6H4-CH2C1 either with oligomer A and optionally methylbenzyl chloride or with a mixture of xylene and methylbenzyl chloride.
The present invention also provides a process for the synthesis of (methylbenzyl)xylene oligomers which is characterised in that the condensation of methylbenzyl chloride CH3-C6H4-CH2C1 with xylene or with the lower oligomers of (methylbenzyl)xylene is carried out in the presence of a Friedel and Crafts catalyst.
The lower oligomers of (methylbenzyl)xylene are similar to the oligomers of (methylbenzyl)xylene, but contain fewer methylbenzyl units. For example, (methylbenzyl)xylene (n3 + n2 = 0) is a lower oligomer of (methylbenzyl)xylene when compared with di(methylbenzyl)xylene (n3 + n2 = 1) .
The condensation of methylbenzyl chloride can be performed with a mixture of xylene and of lower oligomers of (methylbenzyl)xylene. Condensation in the presence of a
Friedel and Crafts catalyst is a reaction which is known per se. In practice it takes place at a temperature of, say, to 130°C. The quantity of catalyst is usually from 50 ppm to 1% by weight of the reaction mass. As an example, Friedel and Crafts catalysts have been described in EP-A-136,230.
After distillation of the excess xylene it is recommended to remove the catalyst by any known technique such as washing with water, neutralisation or drying.
A simple distillation then suffices in order to separate the various (methylbenzyl)xylene oligomers. The reaction mixture which has just been obtained after the condensation and which consists essentially of (methylbenzyl)xylene oligomers and of a possible excess of xylene may contain organic chlorinated products such as:
- chloroxylenes, for example:
and in general (methylbenzyl)xylene oligomers bearing one or more chlorine atoms on the benzene nucleus. These products have been introduced by, or have been formed from the impurities in methylbenzyl chloride or possibly by the Friedel and Crafts catalyst. For some applications it is desirable that the (methylbenzyl)xylene oligomers should contain very little or no chlorine whatsoever. According to a particular form of the invention, the (methylbenzyl)xylene oligomers are treated to remove the organic chlorinated products. It is recommended to perform the treatment after the removal of excess xylene and of the catalyst.
After the condensation reaction the excess xylene is therefore removed, followed by the catalyst, and a removal of the organic chlorine can be performed on this crude, mixture of (l ithylbenzy 1)xylene oligomers.
Any process for destroying organic chlorinated products may be employed, for example the process described in EP-A-306,398, employing an alkali metal alcoholate, or the process described in EP-A-250,748 employing a heavy alcoholate. It is preferred to employ the dechlorination process described in EP-A-306,398.
According to a preferred process the crude mixture is placed in contact with an alcoholate and the whole is heated with stirring to a temperature of, say, 220 to 320°C.
The alcoholate is preferably a sodium alcoholate, for example sodium methylate.
After the dechlorination treatment a simple distillation generally suffices in order to recover the (methylbenzyl)xylene oligomers of low chlorine content. A heavy fraction is usually obtained as tail product, containing the dechlorinating agent residues, an alkali metal chloride (NaCl) and heavy (methylbenzyl)xylene oligomers.
This heavy fraction which is obtained as a residue can be recycled, partially or completely, by itself or mixed with the product used to destroy organic chlorinated products.
It is also possible after the condensation and the removal of xylene for all or part of the (methylbenzyl)xylene to be recycled to the condensation stage. The advantage of this recycling is that it increases the proportion of di(methyl!inzyl)xylene in the oligomers. The removed xylene can be reemployed upstream in the process. All or some of the (methylbenzyl)xylene can also be removed after the dechlorination and recycled to the condensation stage.
The methylbenzyl chloride may also contain xylene dichloride (CH2C1-C6H4-CH2C1). Oligomers B are then obtained, mixed with the (methylbenzyl)xylene oligomers (A).
It is also possible to carry out a radical chlorination of xylene and the condensation is then carried out directly on this mixture. After the chlorination it suffices to add the Friedel and Crafts catalyst to the said mixture.
It is obvious that the process described may be carried out continuously or not continuously.
We have also found that if the process of the invention is carried out with ferric chloride as Friedel and Crafts catalyst, then it is unnecessary to remove the catalyst, that is to say that the mixture obtained after the condensation reaction can be distilled to obtain firstly xylene and then the (methylbenzyl)xylene oligomers possibly with oligomers B, all these oligomers being suitable for dielectric use. This is not true in the case of aluminium chloride; if aluminium chloride is not removed after the condensation, very frequently the mixture of oligomers cannot even be distilled. If (methylbenzyl)xylene oligomers are successfully recovered, then they are unsuited for
- dielectric use. We have also found th c the fact of employing ferric chloride as condensation catalyst not only makes it possible to avoid its removal treatment, but that the eventual destruction of the organic chlorinated products as described previously can be carried out as soon as the condensation is finished. Nevertheless, it is recommended to reaction is finished.
After the dechlorination treatment a simple distillation generally suffices to recover the (methylbenzyl)xylene oligomers and optionally oligomers B with a low chlorine content. The tail product obtained is a heavy fraction containing the residues of the dechlorinating agent, alkali metal chloride, iron salts and heavy oligomers. As before, this heavy fraction can be recycled and can be used as a contribution to the dechlorinating agent.
The following Examples further illustrate the present invention.
EXAMPLE 1
424 g of ortho-xylene (4 moles) are placed in a 15 reactor fitted with a stirrer, a condenser, a chlorine feed tube and a 30-watt Philips TLADK lamp; 71 g of gaseous chlorine (1 mole) are then introduced while the temperature is maintained at 80°C for 1 hour.
After the photochemical initiation is stopped, the 20 reaction mixture is placed in a dropping funnel and is introuuced over 1 hour into a reactor fitted w~ch a stirrer, containing 2 moles of ortho-xylene and 60 mg of FeCl3 at a temperature of 100°C. After the end of addition the whole is kept for another 1 hour at 100°C. Excess ortho-xylene is removed by distillation at a vacuum of 10 mm of mercury with a column of a few plates so as to make the residual ortho- 10 xylene content in the tail product lower than 500 ppm (tail product temperature at the end of distillation = 190°C).
A mixture of polyarylalkane oligomers of type A and B is obtained with iron chloride in suspension. The composition of the organic part is as follows:
ortho-xylene consumed is 97%.
This mixture is then subjected to a treatment with
2% sodium methylate for 6 hours at 300°C under a nitrogen blanket. The mixture resulting from this treatment is subjected to a distillation with a few plates at 0.5 mm of mercury. The following are obtained:
l) a colourless liquid fraction distilling at the temperature of 120-140eC, consisting of product A nl + n2 = °* This product will be called XX01 (methylbenzyl) xylene.
2) a viscous, light-yellow liquid fraction distilling at the temperature of 195-215eC and crystallising slowly at room temperature. The weight composition is the following:
- 11 75% of compound A + n2 = 1 di(methylbenzyl)xylene
% of compound B Sn = 0
This fraction will be called XX02.
The chlorine content in both fractions is lower 5 than 5 ppm.
EXAMPLE 2
Different liquids were compared by measuring their breakdown voltage for 50-Hz alternating current under the following 2 conditions (methods 1 and 2):
1 - 2000 V/s gradient - unsymmetrical electrodes
- 0.6 mm diameter point
- Rogowski disc with rounded edges, 39.6 mm diameter
- interelectrode distance - 3.2 mm
- 1000 V/30s gradient - unsymmetrical electrodes 15 - 0.6 mm diameter point
- 39.6 mm diameter disc
- 3.2-10-15-20 mm distance
The results are reported in the table below:
LIQUID Mineral oil 29 9 (27.3-34.9) (5) 25.4 (21.5-28.5) (10) 34.3 (28-41.5) 35.6 (30-38) (10) 45.6 (39.5-56.0) (10) DDB 39.0 (34.9-44.4) (10) (01) PXE 47.9 (43.5-52) (10) 37.8 (34-39.7) (5) 53.2 (48.2-58.7) (6) 75.8 (69.0-84.5) (5) 74.7 (71.0-76.5) (5) XX01 53.0* (48.6-57.2)** (5)*** 41.2 (37.7-45.3) (5) 69.5 (65.3-75.8) (5) 82.4 (74-89) (5) 93.8 (90.0-105.0) (5) Inter, d mm 3.2 i 1 3.2 o i-H m o CN Electrode point 0 = 0.6 disc 0 = 39.6 point 0 = 0.6 disc 0 = 39.6 Voltage gradient 2000V/S & fr » S 1 8 • rH CM
* *
* ·*
α η
- 13 XX01 denotes a product of Example 1, PXE denotes a product sold under the name of Nisseki Condensor Oil S which is a mixture of 1-phenyl-l-xylylethane and of 1-phenyl1-ethylphenylethane.
DDB denotes branched dodecylbenzene; the mineral oil is a commercial transformer oil.
EXAMPLE 3
Crystallisation of product XX01 from Example 1, of product XX02 from Example 1, and of a mixture of 85% by weight of XX01 and 15% by weight of XX02 (see Example 1), which is called XX05.
XX05 therefore consists of:
- 85 parts of A/n^ + n2 = 0
- 15 parts of XX02 containing 75% of A/n3 + n2 = 1 15 and 25% of B/Sn - 0, that is to say:
x 0.75 = 11.25 parts of A/n-L + n2 = 1 x 0.25 = 3.75 parts of B/Sn = 0
XX01 crystallises at -40°C, XX02 is crystalline at room temperature and XX05 has not yet crystallised at -50°C.
An onset of crystallisation in some samples of XX05 appears after several months.
' EXAMPLE 4
The same tests as in Example 3 are carried out, but with products XX01 and XX02, which are prepared as in
Example 1 except that a mixture of 75% of ortho-xylene and 25% of para-xylene or else 100% of ortho-xylene is employed.
None of the samples XX05 show any onset of crystallisation, even after several months.
Claims (16)
1. Use as a dielectric fluid of the following oligomer A or B or a mixture thereof, oligomer A being a mixture of isomers of formula: in which n x and n 2 independently = 0 n l + n 2 i s i ess than or equal to 3, mixture of isomers of formula: , 1 or
2. Such that and oligomer B being a ch 3 ch 3 - 16 in which n' x , n 3 and n 4 independently = 0, 1 or 2, and n' 2 , n” 2 , n 3' n *3 and n 5 independently = 0 or 1 such that n’x + n' 1 ! + n’2 + n 2 + n 3 + n’ 3 + n 4 + n 5 , which is denoted by Sn, is less than or equal to 2. 5 2. A composition comprising a mixture of isomers of formula: in which n x and n 2 independently = 0, 1 or 2 such that n l + n 2 l ess than or equal to 3, and such that it 10 comprises oligomers where n x + n 2 = 0 and oligomers where n l + n 2 = l.
3. A composition according to Claim 2, in which the weight ratio of the oligomers where n x + n 2 = 0 and the oligomers where n x + n 2 = 1 is from 95/5 to 70/30. 15
4. A composition according to Claim 3, in which the said weight ratio is from 85/10 to 80/20.
5. A composition according to Claim 2 substantially as described in any one of the Examples.
6. Process for the synthesis of a 20 (methylbenzyl)xylene oligomer, which comprises condensing methylbenzyl chloride with xylene or with a lower oligomer of (methylbenzyl)xylene in the presence of a Friedel and Crafts catalyst. - 17
7. Process according to Claim 6, in which after the condensation the organic chlorinated products are removed by reaction with sodium or an alkali metal alcoholate. 5
8. Process according to Claim 7 in which the organic chlorinated products are removed by reaction with sodium methylate.
9. Process according to any one of Claims 6 to 8, in which all or part of the (methylbenzyl)xylene is recycled 10. To the condensation stage.
10. Process according to any one of Claims 6 to 9, in which the heavy fraction which is obtained in the distillation in order to recover the (methylbenzyl)xylene oligomers of low chlorine content is partially or completely 15 recycled to the stage of removal of the organic chlorinated products.
11. Process according to any one of Claims 5 to 10, in which ferric chloride is employed as condensation catalyst. 20
12. Process according to Claim 11, in which the removal of the organic chlorinated products is carried out without the ^erric chloride having been removed.
13. Process according to claim 6 substantially as described in Example 1. 25
14. A (methylbenzyl)xylene oligomer whenever synthesised by a process as claimed in any one of Claims 6 to 13.
15. Use as a dielectric fluid of a composition as claimed in any one of Claims 2 to 5 or of an oligomer as claimed in Claim 14.
16. Use according to Claim 1 or 15 in a capacitor, 5 transformer or cable.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR9002013A FR2658655B1 (en) | 1990-02-20 | 1990-02-20 | PROCESS FOR THE SYNTHESIS OF (METHYLBENZYL) XYLENE OLIGOMERS AND THEIR APPLICATION AS DIELECTRIC. |
| CN91101395A CN1037092C (en) | 1990-02-20 | 1991-03-08 | Process for synthesis of (methylbeneyl) xylene oligomers and their application as dielectric |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| IE910562A1 true IE910562A1 (en) | 1991-08-28 |
Family
ID=36764655
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| IE056291A IE910562A1 (en) | 1990-02-20 | 1991-02-19 | Process for the synthesis of (methylbenzyl)xylene oligomers¹and their application as a dielectric |
Country Status (11)
| Country | Link |
|---|---|
| EP (1) | EP0443899A1 (en) |
| JP (1) | JP2507277B2 (en) |
| CN (1) | CN1037092C (en) |
| BR (1) | BR9100668A (en) |
| CA (1) | CA2036569A1 (en) |
| FI (1) | FI910803A (en) |
| FR (1) | FR2658655B1 (en) |
| IE (1) | IE910562A1 (en) |
| NO (1) | NO910633L (en) |
| PT (1) | PT96813B (en) |
| ZA (1) | ZA911255B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2794567A1 (en) * | 1999-06-07 | 2000-12-08 | Atofina | DIELECTRIC COMPOSITION HAVING IMPROVED GAS ABSORPTION |
| FR2794566B1 (en) * | 1999-06-07 | 2001-08-24 | Atofina | DIELECTRIC COMPOSITION HAVING IMPROVED GAS ABSORPTION |
| JP2020143832A (en) | 2019-03-06 | 2020-09-10 | 日本電産サンキョー株式会社 | Ice making apparatus |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2552423B1 (en) * | 1983-09-23 | 1985-10-25 | Ugine Kuhlmann | POLYARYLALCAN OLIGOMER COMPOSITIONS AND THEIR MANUFACTURING METHOD |
| FR2618142B1 (en) * | 1987-07-16 | 1989-10-06 | Atochem | POLYARYLALKANE OLIGOMER COMPOSITIONS CONTAINING XYLENE PATTERNS AND THEIR MANUFACTURING METHOD |
| US4956120A (en) * | 1987-07-16 | 1990-09-11 | Atochem | Polyarylalkane oligomer compositions and process for their manufacture |
-
1990
- 1990-02-20 FR FR9002013A patent/FR2658655B1/en not_active Expired - Fee Related
-
1991
- 1991-02-07 EP EP19910400299 patent/EP0443899A1/en not_active Ceased
- 1991-02-18 NO NO91910633A patent/NO910633L/en unknown
- 1991-02-19 IE IE056291A patent/IE910562A1/en unknown
- 1991-02-19 BR BR919100668A patent/BR9100668A/en not_active Application Discontinuation
- 1991-02-19 FI FI910803A patent/FI910803A/en not_active Application Discontinuation
- 1991-02-19 PT PT96813A patent/PT96813B/en not_active IP Right Cessation
- 1991-02-19 CA CA002036569A patent/CA2036569A1/en not_active Abandoned
- 1991-02-20 ZA ZA911255A patent/ZA911255B/en unknown
- 1991-02-20 JP JP3047755A patent/JP2507277B2/en not_active Expired - Lifetime
- 1991-03-08 CN CN91101395A patent/CN1037092C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| EP0443899A1 (en) | 1991-08-28 |
| FR2658655A1 (en) | 1991-08-23 |
| NO910633D0 (en) | 1991-02-18 |
| FI910803A0 (en) | 1991-02-19 |
| FR2658655B1 (en) | 1994-07-22 |
| ZA911255B (en) | 1991-11-27 |
| JP2507277B2 (en) | 1996-06-12 |
| PT96813B (en) | 1998-07-31 |
| CA2036569A1 (en) | 1991-08-21 |
| CN1064672A (en) | 1992-09-23 |
| BR9100668A (en) | 1991-10-29 |
| FI910803A (en) | 1991-08-21 |
| NO910633L (en) | 1991-08-21 |
| JPH04211025A (en) | 1992-08-03 |
| PT96813A (en) | 1991-10-31 |
| CN1037092C (en) | 1998-01-21 |
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