Method of making a dialdeyhde

Abstract

Disclosed is a two-step process to make a dialdehyde. In the process a diepoxide is first hydrolyzed with an alcohol solvent to an intermediate which is then subjected to a double-Pinacol rearrangement to obtain a dialdehyde. The dialdehydes have utility as chemical intermediates, and particular utility in processes to make enol ether compounds which can be used in applications as plasticizers, diluents, wetting agents, coalescing aids and as intermediates in chemical processes.

Claims

1. A method for making dialdehydes from diepoxides comprising: a) combining an alcohol with a diepoxide in the presence of a base to form a first mixture; b) heating said first mixture to form a second mixture; c) adding an acid to the second mixture to form a third mixture; and d) separating dialdehyde from the third mixture.

2. The method of claim 1 wherein said diepoxide is selected from the group comprising 1,3-bis(2-methyloxiran-2-yl)benzene, 1,4-bis(2-methyloxiran-2-yl)benzene, 1,3-di(oxiran-2-yl)benzene, 1,4-di(oxiran-2-yl)benzene 4,4-bis(2-methyloxiran-2-yl)-1,1-biphenyl, and 2,6-bis(2-methyloxiran-2-yl)naphthalene and mixtures thereof.

3. The method of claim 1 wherein said alcohol is selected from the group consisting of methanol, ethanol, n- and iso-propanol, n-butanol, and sec-butanol and mixtures thereof.

4. The method of claim 1 wherein said acid is selected from the group consisting of acetic acid, formic acid, chloroacetic acid, dichloroacetic acid, trichloroacetic acid, and trifluoroacetic acid and mixtures thereof.

Description

DETAILED DESCRIPTION

Definitions

(1) In this specification and in the claims that follow, reference will be made to a number of terms, which shall be defined to have the following meanings.

(2) Alcohol means a chemical containing one or more hydroxyl groups.

(3) Aldehyde means a chemical containing one or more C(O)H groups.

(4) As used herein, the terms a, an, and the mean one or more.

(5) As used herein, the term and/or, when used in a list of two or more items, means that any one of the listed items can be employed by itself or any combination of two or more of the listed items can be employed. For example, if a composition is described as containing components A, B, and/or C, the composition can contain A alone; B alone; C alone; A and B in combination; A and C in combination, B and C in combination; or A, B, and C in combination.

(6) As used herein, the terms comprising, comprises, and comprise are open-ended transition terms used to transition from a subject recited before the term to one or more elements recited after the term, where the element or elements listed after the transition term are not necessarily the only elements that make up the subject.

(7) As used herein, the terms having, has, and have have the same open-ended meaning as comprising, comprises, and comprise provided above.

(8) As used herein, the terms including, includes, and include have the same open-ended meaning as comprising, comprises, and comprise provided above.

(9) Presented herein is a process to directly convert a diepoxide to a dialdehyde via a novel synthesis method.

(10) Mono-epoxide to mono-aldehyde rearrangements are well known. However, when attempting to extend scope to di-aldehyde to di-epoxide rearrangement, there are few chemistry options. For example, common Lewis acids and Bronsted acids lead to oligomerization and the production of complex mixtures of products when a difunctional rearrangement is attempted. The inventors tested tritylium tetrafluorborate, boron trifluoride, zinc chloride, methanesulfonic acid, solid supported acids (e.g. Amberlyst 15, Nafion NR50)all of which led to oligomerization. Other catalysts that have were screened include kaolinte, bentonite, Zeolite Y, acidic aluminum oxide, and silica gel. These processes all resulted in no reaction.

(11) We have discovered a two-step process employing methanolysis of an aromatic diepoxide to a dicarbinol followed by an acid-catalyzed rearrangement to successfully produced dialdehydes.

(12) The method comprises: a) combining an alcohol with a diepoxide in the presence of a base to form a first mixture; b) heating said first mixture to form a second mixture; c) adding an acid to the second mixture to form a third mixture; and d) separating dialdehyde from the third mixture.

(13) Di-epoxides suitable for the method include 1,3-bis(2-methyloxiran-2-yl)benzene, 1,4-bis(2-methyloxiran-2-yl)benzene, 1,3-di(oxiran-2-yl)benzene, 1,4-di(oxiran-2-yl)benzene 4,4-bis(2-methyloxiran-2-yl)-1,1-biphenyl, and 2,6-bis(2-methyloxiran-2-yl)naphthalene and mixtures thereof.

(14) Acids suitable for the method include acetic acid, formic acid, chloroacetic acid, dichloroacetic acid, trichloroacetic acid, and trifluoroacetic acid and mixtures thereof.

(15) Alcohols suitable for the method include methanol, ethanol, n- and iso-propanol, n-butanol, and sec-butanol and mixtures thereof.

(16) This invention can be further illustrated by the following examples thereof, although it will be understood that these examples are included merely for purposes of illustration and are not intended to limit the scope of the invention unless otherwise specifically indicated.

Abbreviations

(17) wt % is weight percent; hrs or h is hour(s); mm is millimeter; m is meter; GC is gas chromatography; C. is degree Celsius; min is minute; t.sub.R is retention time; g is gram; mmol is millimole; mol is mole; mL is milliliter; L is liter; L is microliter.

EXAMPLES

Example 1: Preparation of 2,2(1,4-phenylene)bis(1-methoxypropan-2-ol) [2]

(18) ##STR00001##

(19) KOH (49.2 g, 788 mmol) was dissolved in MeOH (400 mL) contained within a 1 L, 4-necked round-bottom flask fitted with thermocouple, overhead stirrer, and nitrogen inlet atop a reflux condenser. During the addition of KOH, internal temperature reached 60 C. and was maintained there by heating mantle. 1,4-bis(2-methyloxiran-2-yl)benzene [1] was added over the course of 1.5 hrs. The reaction was monitored by .sup.1H NMR (aliquot was taken and dissolved in DMSO-d.sub.6. Once the di-epoxide was completely consumed, the reaction was cooled to ambient temperature, and acetic acid (47.3 g, 788 mmol) was added dropwise. Once addition was complete, the volatiles were removed under reduced pressure using a rotary evaporator. The residue was taken up in 250 mL of toluene and then washed with 250 mL of water. The aqueous layer was back-extracted with 250 mL of EtOAc using a separatory funnel. The organics were combined, dried with MgSO.sub.4 and simultaneously treated with 5 g of activated carbon. The mixture was filtered, and volatiles were removed under reduced pressure using a rotary evaporator. 2,2-(1,4-phenylene)bis(1-methoxypropan-2-ol) [2] was isolated as a white solid [LC-MS (Column A) t.sub.R: 3.80 min (Exact mass: 254.15 m/z, found 254.2 m/z)]/.

Example 2: Preparation of 2,2-(1,4-phenylene)dipropanal [3]

(20) ##STR00002##

(21) The 2,2-(1,4-phenylene)bis(1-methoxypropan-2-ol) [2] then dissolved in formic acid (88%, 98.0 g) contained within a 500 mL, 4-necked round-bottom flask fitted with thermocouple, overhead stirrer, and nitrogen inlet atop a reflux condenser. The mixture was heated to 100 C. After 6 hrs, additional formic acid was added (98.0 g). After an additional 2 hrs, GC indicated >99% conversion to 2,2-(1,4-phenylene)dipropanal [3]. The volatiles were then removed under reduced pressure using a rotary evaporator. The residue was taken up in 250 mL of toluene and then washed with a saturated solution of NaHCO.sub.3. After layer separation, the organics were dried with MgSO.sub.4, filtered, and then concentrated. The crude material was then Kugelrohrdistilled at 150 C./1 mm Hg to isolate the 2,2-(1,4-phenylene)dipropanal [3] as a colorless oil. GC-MS t.sub.R: 14.47 min (Exact mass: 190.10 m/z, found: 190.1 m/z).

Example 3: Preparation of 2,2-(1,3-phenylene)bis(1-methoxypropan-2-ol) 5 and 2,2-(1,3-phenylene)dipropanal [6]

(22) ##STR00003##

(23) 2,2-(1,3-phenylene)bis(1-methoxypropan-2-ol) [5] was prepared in a similar manner to 2,2-(1,4-phenylene)bis(1-methoxypropan-2-ol) [2] using the dicarbinol preparation procedure described herein above. [LC-MS (Column B) t.sub.R: 4.55 min, 4.68 min (Exact mass: 254.15 m/z, found 254.2 m/z)]. 2,2-(1,3-phenylene)dipropanal [6] was prepared using the di-aldehyde preparation procedure described herein above. [GC-MS t.sub.R: 14.22 min (Exact mass: 190.10 m/z, found: 190.1 m/z)].

(24) Instrument ParametersAgilent 6890N GC with Agilent 5975B VL MSD

(25) Sample Prep: 100 L sample diluted to 1 mL with toluene; Column: DB-5 30 m0.25 mm0.25 m; Oven Ramp: 0-4.5 mins at 40 C.; Ramp 20 C/min to 280 C, Hold up to 85 mins; Injector: Temperature250 C.; Split Flow65 mL/min; Carrier Flow Rate1.3 mL/min; Volume1.0 L; MS: Transfer Line280 C.; Ion Source Temp230 C.; Mass Range34-700 amu.

(26) ConditionsAgilent 1100 LC Sample Prep: 2-3 mg/mL in DMSO Column A: Zorbax XDB-C184.6 mm, 5 m Column B: Poroshell EC-C18 504.6 mm, 2.7 m Column Temp: 40 C. Injection Volume: 2 L DAD: 190-600 nm collection Pump Conditions: Initial97% water (2.5 mM NH.sub.4OAc) (Solvent A) and 3% acetonitrile (Solvent B) Gradient:

(27) TABLE-US-00001 Time % Solvent % Solvent Flow (min) A B (mL/min) 0 97 3 1.0 10 0 100 1.0 25 0 100 1.0 25.1 97 3 1.0 30 97 3 1.0 Mass spectra were acquired with a Micromass LCT mass spectrometer, which was coupled to the LC. Mass spectra were collected using electrospray ionization in both the positive-ion and negative ion modes. Ammonium acetate (50 mM in MeOH) was added post column (0.1 mL/min) to enhance ionization efficiency. ES.sub.+/ES.sub. scan range was 60-3300 amu (25 and 75V).

(28) The invention has been described in detail with reference to the embodiments disclosed herein, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention.