JPS6254779B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing bisphenol and bisphenol produced by the method. In the production of bisphenols, such as bisphenol A, it is well known to react continuously in a reaction zone at least 2 moles of phenol with a carbonyl compound in the presence of an acidic ion exchange resin. At that time, the effluent from the reaction zone contains unreacted carbonyl compounds, phenol,
It is a mixture of water, bisphenol and reaction by-products. Some of the bisphenols and phenols can be in the form of adducts. It is possible to separate all of the carbonyl compounds and water and some of the phenols from the reaction zone effluent and recover the bisphenols from the remaining reaction zone effluent (see, for example, GB 883,391). Surprisingly, Applicants have now discovered that if the remaining reaction zone effluent is recycled into the reaction zone, the remaining reaction zone effluent can be recycled without adversely affecting the properties of the acidic ion exchange resin or the properties of the recovered phenol. It has been discovered that the bisphenol concentration in the reaction zone effluent can be substantially increased. The invention therefore relates to a continuous process for the production of bisphenols, in which at least 2 moles of phenol are reacted with a carbonyl compound in the presence of an acidic ion exchange resin in a reaction zone; The reaction zone effluent was distilled into 2
The first stream contains unreacted carbonyl compounds, water and phenols, the second stream contains bisphenols, reaction by-products and phenols, and the second stream contains bisphenols. a portion of the second stream is recycled to the reaction zone prior to recovering bisphenols from the second stream. The reaction zone is a single reactor or two
One or more reactors in series. In the case of a multi-reactor reaction zone, all the phenols are fed to the first reactor and the carbonyl compounds are either fed entirely to the first reactor or to the second reactor and other reactions if present. It is appropriate to divide it between the containers. As previously discussed, the reaction zone effluent separates into two streams. This separation is suitably carried out by distilling off all unreacted carbonyl compounds and water and some of the phenol. The reaction zone effluent depends on the reaction zone temperature and the pressure used to achieve the above separation.
Can be heated or cooled. In the case of a distillation column, it is appropriate to maintain its temperature between 130 and 220°C, and its pressure to be sufficient to completely remove carbonyl compounds and a portion of water and phenols from the reaction zone effluent. If so, it is appropriate.
In practice, only minimal amounts of phenol are removed while unreacted carbonyl compounds and water are completely removed. The stream thus removed, which preferably amounts to 1 to 10% by weight of the reaction zone effluent, can be further processed to recycle unreacted carbonyls and phenols. The separated remainder, the second stream, contains bisphenols, reaction by-products and phenols. The amount of phenol in this stream is suitably 4 to 15 moles per mole of bisphenol. An important feature of the invention is that a portion of this second stream is recycled to the reaction zone. In a preferred embodiment of the invention, the circulation ratio (weight ratio) of the circulation stream to the remainder of the second stream is in the range 0.2:1 to 4:1; ratio is particularly desirable. The bisphenol can be recovered from the remainder of this second stream by conventional techniques, such as by removing the phenol therefrom by evaporation.
Bisphenols can also be recovered by crystallization. Suitable acidic ion exchange resins for use in this invention are those having a structure such that the resin is insoluble in the reaction medium. Desirable resins contain a large number of sulfonic acid groups. Such sulfonated ion exchange resins can be sulfonated styrene divinylbenzene copolymers and sulfonated phenol formaldehyde resins. The sulfonated resin is commercially available in dry or water-swollen form, and either form can be used in the present method. Specific examples of suitable resins include:
Amber Light IR-120H, Amber List
15H, Dowex 50-X-4, Dowex MSC-1H, Duolite
C-26, Palmchit QH, Chempro C-20, and Imac
It is C8P/H ⁺ . (Amberlite, Amberlyst, Dowex, Duolite, Palmtit, Chempro and Eyemack are all registered trademarks). The exchange capacity of the acidic resin is preferably at least 2.0 meq H ⁺ /g (dry resin), and particularly preferably from 3.0 to 5.5 meq H ⁺ /g (dry resin). Acidic ion exchange resins can be partially modified with compounds having acidic reactive groups and mercaptan groups. This improvement can be made as follows. by partial esterification of the resin with mercapto alcohols (see, for example, British Patent No. 937,072), or by partial neutralization of the resin with alkylmercaptoamines, such as thioethanolamine (see, for example, Belgian Patent No. 589,727 and GB Patent No. 1183564), mercaptoamines such as thiazolidine precursors (see e.g. GB Patent No. 1361430), cyclomercaptoamines and mercaptoaminocarboxylic acids, and thiazolidine precursors of the latter (e.g. Applicant's pending patents No. 32251/75 and No.
32878/75). Among the acidic groups, 2 to
It is appropriate that 25% is improved, preferably 5%.
~20% improvement is desirable. As an alternative to such improved methods, the reaction can be carried out in the presence of dissolved ionic compounds as cocatalysts. Such sulfur compounds include, for example, alkyl mercaptans such as methyl and ethyl mercaptan and mercapto-substituted aliphatic carboxylic acids such as 3-mercaptopropionic acid. The reactor can be filled with acidic ion exchange resin by well known techniques. Such techniques include adding the required amount to the reactor as a dry resin, a water-swollen resin, or a slurry containing the resin. The resin bed is suitably fixed and usually supported by one or more grid plates. Suitable phenols for use in this invention must have a reactive hydrogen atom, preferably a hydrogen atom in the para position with respect to the phenol hydroxyl group. Such phenols may be substituted by one or more alkyl groups such as lower alkyl groups such as methyl or tert-butyl groups, halogen atoms such as chlorine atoms or other non-interfering substances. Specific examples of phenols include ortho- or meta-cresol, 2.
6-dimethylphenol, ortho-sec-butylphenol, ortho-tert-butylphenol, 2.
6-di-tert-butylphenol, 1,3,5-xylenol, tetramethylphenol, 2-methyl-6-tert-butylphenol, ortho-phenylphenol, ortho- and meta-chlorophenol, ortho-bromophenol , 6-cro-
orthocresol, and 2,6-dichlorophenol. Phenol itself is also desirable for use. The carbonyl compound used in this method can be an aldehyde or a ketone, the latter being preferred. Preferred ketones are those having at least one methyl group in the alpha position with respect to the carbonyl group or are cyclic ketones. Specific examples are acetone, methyl ethyl ketone, methyl propyl ketone, acetophenone, methyl vinyl ketone and cyclohexanone. Acetone is the preferred ketone. This invention is particularly useful in 2.2
- Suitable for producing bis(4-hydroxyphenyl)propane (bisphenol A). The molar ratio of phenol and carbonyl compound is
A stoichiometric excess of phenol of at least 2 is desirable. A suitable molar ratio is 3:1 to 50:
1, and a molar ratio of 10:1 to 30:1 is desirable.
The optimum molar ratio depends, inter alia, on the reaction conditions, such as the reaction temperature and the desired conversion. The reaction temperature in the reaction zone can vary over a wide range, with reaction temperatures in the range of 30°C to 120°C being preferred, and reaction temperatures in the range of 40°C to 100°C being particularly preferred. The reaction time in the reaction zone can also vary within upper and lower limits and depends inter alia on the reaction temperature.
For example, average contact times between 3 minutes and 10 hours can be used. The hourly average space velocity (LHSV) of the feedstock feed can also vary within upper and lower limits, with space velocities in the range of 0.2 to 40 (feed stream)/(catalyst) (Hr) being preferred. The bisphenols thus produced can be used in a variety of applications, such as in the production of antioxidants, epoxy resins and polycarbonate resins. This method will be explained based on the drawings. The accompanying drawings are schematic illustrations of preferred embodiments of the invention. In this embodiment, feed stream 1 contains phenols and carbonyl compounds and is fed continuously to reaction zone R, which contains a fixed bed of acidic ion exchange resin. The effluent of the reaction zone R is continuously withdrawn and fed to the distillation column D, and the overhead distillate stream 3 containing all of the carbonyl compound and water and a part of the phenol is continuously withdrawn. process. Bottoms stream 4, containing bisphenols, reaction by-products and phenols, is continuously withdrawn from the column, a portion of which is recycled to reaction zone R as stream 5. The remaining portion, stream 6, is further processed to recover the bisphenols. The invention will be further illustrated with reference to the following examples. Example 1 A tubular reactor (length 150 cm, inner diameter 2 cm) and a distillation column (length 150 cm, inner diameter 2 cm) are connected in series, and the reactor contains 130 g (dry basis) of sulfonated styrene/
An aqueous slurry containing divinylbenzene acidic ion exchange resin was partially filled and the water was allowed to drain to form a fixed bed of resin. The ion exchange resin was previously partially neutralized (10%) with thioethanolamine and had an exchange capacity of 4.25 meq H ⁺ /g (dry resin). The reactor was maintained at a temperature of 65°C and the distillation column was maintained at a temperature of 194°C. The feed stream containing phenol and acetone was
/ (catalyst) (Hr), the effluent from the reactor is continuously extracted and supplied to the distillation column, and the overhead stream (distillate stream) is ) and a bottom stream (recovery stream) were continuously withdrawn. After 120 hours of operation, the acetone conversion was 52% based on the intake amount, and the composition of each stream was as shown in the following table.

[Table] 〓 〓 〓 〓 〓 〓 〓 〓 〓 〓 〓 〓 〓
〓 〓 〓 〓 〓 〓 〓 〓 〓
Upon removal of phenol from the recovered stream by evaporation, the recovered diphenylolpropane (DPP) is separated from its ortho/para DPP and para/para
The ratio to DPP was 2.1/97.9, and a hue of 54 Hazen was exhibited. The amount of phenol removed by evaporation from the recovered stream was 11.29 g/g (diphenylolpropane). Example 2 Example 1 was repeated, except that 60% of the bottom stream from the distillation column was continuously recycled to the reaction zone (recirculation ratio 1.5:1). The hourly liquid hourly space velocity of the reactor feed stream (new raw material feed stream plus circulation stream) was 6/(catalyst)·(Hr). 120 hours after the start of the reaction, the acetone conversion rate was 51% based on the amount taken in, and the composition of each stream was as shown in the table below.

[Table] Lupropane water − 0.52 22 − −
By-products 0.1 0.2 − 0.2 0.2
〓 〓 〓 〓 〓 〓 〓 〓 〓 〓 〓 〓 〓
〓 〓 〓 〓 〓 〓 〓 〓 〓
The recovered diphenylopropane has a ratio of ortho/para DPP to para/para DPP of 2.2/
It was 97.8 and showed a hue of 54 Hazens. The amount of phenol removed by evaporation from the recovered stream was 4.9
g/g (diphenylolpropane).

[Brief explanation of the drawing]

The drawings are schematic illustrations of embodiments of the invention. R...Reaction zone, D...Distillation column, 1...Raw material feed stream, 2...Effluent from reaction zone R, 3...Tower top distillate stream, 4...Tower bottom stream, 5...Recirculation flow , 6...Recovery flow.

Claims (1)

[Claims] 1. In the production of bisphenol, at least 2 moles of phenol are reacted with a carbonyl compound in the presence of an acidic ion exchange resin in a reaction zone, and the effluent from the reaction zone is distilled. and separating into two streams, the first stream containing unreacted carbonyl compound, water and phenol, and the second stream containing bisphenols, reaction by-products, and phenols; A continuous method comprising recovering bisphenols from a stream, characterized in that a portion of the second stream is recycled to the reaction zone prior to recovering bisphenols from the second stream. Continuous process for producing bisphenols. 2. The method according to claim 1, characterized in that the circulation ratio is between 0.2:1 and 4:1. 3. A process according to claim 1 or 2, wherein the first stream is 1 to 10% by weight of the reaction zone effluent. 4. Claims 1 to 3, wherein the acidic ion exchange resin is a sulfonated styrene-divinylbenzene copolymer optionally partially neutralized with an alkylmercaptoamine. A method as described in any one section. 5 The molar ratio of phenol and carbonyl compound is
5. A method according to any one of claims 1 to 4, characterized in that the ratio is between 10:1 and 30:1. 6. The method according to any one of claims 1 to 5, characterized in that the reaction temperature is 40°C to 100°C.