Europâisches Patentamt ® European Patent Office @ Publication number: 0 068 795 Office européen des brevets B1 ® EUROPEAN PATENT SPECIFICATION ® Date of publication of patent spécification: 13.03.85 © Int. ci.4: C 07 C 69/15, C 07 C 67/297 @) Application number: 82303245.3 (22) Date offiling: 22.06.82 (54) Process for producing vinyl acetate. (§) Priority: 22.06.81 JP 96296/81 ® Proprietor: MITSUBISHI GAS CHEMICAL COMPANY, INC. 5- 2, Marunouchi 2-chome Chiyoda-Ku (§) Date of publication of application: Tokyo (JP) 05.01.83 Bulletin 83/01 (72) Inventor: Isshiki, Tomiya (45) Publication of the grant of the patent: 14-11 Umegaoka 2-chome 13.03.85 Bulletin 85/1 1 Setagaya-ku Tokyo (JP) Inventor: Nawata, Takanari 19-3 Kanamachi 5-chome (84) Designated Contracting States: Katsushika-ku Tokyo (JP) DEFRGBIT Inventor: Kijima, Yasuhiko 641 Kode Matsudo-shi Chiba-ken (JP) (5$) References cited: Inventor: Ito, Akira FR-A-2 413 354 15-6 Nishikubo-cho Tokiwadaira US-A-2 425 389 Matsudo-shi Chiba-ken (JP) Inventor: Watanabe, Takayuki 6- 1 Kanamachi 1-chome 0Û Katsushika-ku Tokyo (JP) m (74) Representative: Ritter, Stephen David et al N Mathys & Squire 10 Fleet Street London EC4Y 1AY (GB) oo o o Note: Within nme months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall Û. be filed in a written reasoned statement. It shall not be deemed to hâve been filed until the opposition fee has been (Art. UJ paid. 99(1 ) European patent convention). Courier Press, Leamington Spa, England. (4) ammonium halides represented by NH4X wherein X is as defined above. This invention relates to a process for The mechanism of the decomposition of producing vinyl acetate which comprises ethylidene diacetate for forming vinyl acetate is decomposing ethylidine diacetate, and par- not perfectly clear. However, it is believed that ticularly relates to a process for producing vinyl the decomposition reaction is expressed by the acetate which comprises carrying out decom- following equation: position of ethylidene diacetate in the presence of a catalyst comprising at least one compound selected from the group consisting of fluorides, chlorides, bromides, iodides, halogens and The above reaction proceeds in a good state mixtures thereof. when a catalyst comprising a halide referred to Vinyl acetate has been produced from above is used. acetylene in the past. Recently vinyl acetate has As indicated, the halides which are usable as also been produced from ethylene. the catalyst in the practice of this invention are In addition, a process for producing vinyl bromides, iodides and mixtures thereof, iodides acetate which comprises producing ethylidene being most preferable. diacetate (1,1-diacetoxy ethane) from acetalde- Examples of the halides which are used as hyde and acetic anhydride, or dimethyl ether or the catalyst of this invention include the follow- methyl acetate and synthesis gas and causing ing. However, compounds which are not listed decomposition of the ethylidene diacetate to in the following paragraphs may also be used as form vinyl acetate (refer to Hydrocarbon the catalyst. Process, 44, (11) 287 (1965), British Patent (1) Lithium halides, including LiBr, No. 1,538,782 and U.S. Patent Nos. 2,021,698; LiBr2 . 2H2O, Lil and Lil · 3H2O. 2,425,389 and 2,860,159). However, known (2) Magnesium halides, including MgBr2, processes for decomposing ethylidene MgBr2 · 6H2O, Mgl2 and Mgl2 . 8H2O. diacetate were unsatisfactory. (3) Calcium halides, including CaCl2, CaBr2, In the prior art, protonic acids, such as Cal2, CaBr2. 6H2O and Cal2 · 6H2O. sulfuric acid, organic sulfonic acids, etc. have (4) Strontium halides, including SrBr2, Srl2, been known as catalysts for decomposing and SrBr2 . 6H2O. ethylidene diacetate. Decomposition of ethyli- (5) Barium halides, including BaBr2, Bal2 and dene diacetate by using such catalysts is BaBr2. 2H2O. unsatisfactory in respect of decomposition rate (6) Zinc halides, including ZnBr2 and Znl2. and selectivity to product. (7) Tin halides, including SnBr2, SnBr4, The present inventors carried out research to SnBr212, Snl2 and Snl4. find a process for efficiently producing vinyl (8) Antimony halides, including SbBr3, Sbl3, acetate from ethylidene diacetate. As a result, Sbl5 found novel catalysts for decomposing we The metal halides be in the state of a ethylidene diacetate to form vinyl acetate. This may hydrate, a double salt or a coordination invention is based this discovery. on compound. Mixtures of two or more metal is An object of this invention to provide a halides may be used. The metal halides may be process for producing vinyl acetate in a high in the form of solid material, powder or finely decomposition rate and in a high selectivity. divided powder. The metal halides may be sup- According to the present invention there is ported on a carrier. Metal halides supported on provided a process for producing vinyl acetate a carrier can easily be separated from the which comprises decomposing ethylidene reaction system. diacetate in the presence of at least one halide (9) Organic halides represented by R1Xp. selected from: wherein p is integer of 1-3 and X is as (1) metal halides selected from metal defined above including: bromides and iodides, and mixtures (a) Compounds wherein R1 is thereof, said metal being selected from saturated alkyl having 1 to 10 Li, Mg, Ca, Sr, Ba, Zn, Sn and Sb; carbon atoms or cycloalkyl having (2) organic halides represented by R1Xp 3-10 carbon atoms, for example wherein R1 is selected from alkyl having CH3Br, CH2BR2, CHBr3, CH31, 1-10 carbon atoms, cycloalkyl having CH2l2, CHl3, CH3CH2Br, CH3CH2l, 3-10 carbon atoms and aromatic ICH2CH2l and C6H11l. hydrocarbon having 6-10 carbon (10) Organic halides represented by R2COX atoms, X is selected from I and Br, and p wherein R2 is saturated alkyl having 1- is 1, 2 or 3; 10 carbon atoms, cycloalkyl having 3- (3) organic halides represented by R2COX 10 atoms or aryl and X is as defined wherein R2 is selected from alkyl having above including CH3COBr, CH3COl, 1-10 carbon atoms, cycloalkyl having CH3CH2COl, C6H11COl and C6H5COl. 3-10 carbon atoms and aryl, and X is as defined above; and Of the metal halides, halides of metals selected from Li, Mg, Ca, Sr, Ba, Zn, Sn and Sb another solvent is not necessary. However, the following, namely Li, Mg, Ca, Sr, Ba and Sb other organic solvents compatible with ethyli- are most preferred. dene diacetate and products under the reaction The amount of catalyst employed depends conditions may be used. Compounds which on whether the catalyst is soluble, insoluble or participate as solvent in the reaction as a partially soluble in the reaction system, or starting material, an object product or a by- whether the reaction is carried out in a fluidized product are preferable. For example, ethylidene or fixed bed when using an insoluble catalyst. In diacetate and acetic anhydride are preferable. general the amount of the catalyst employed Solvents which are usable in this invention may be in the range of 1 x 10-4-90 wt%, pre- include, for example, organic acid esters, such ferably 5xlo-1-85 wt %, most preferably as ethylene glycol diacetate, propylene glycol 1 x 10-2-80 wt % and most preferably 0.1- diacetate, methyl acetate, dimethyl adipate, 75 wt % on the basis of weight of the reaction methyl benzoate, ethyl benzoate, dimethyl solution. phthalate, diethyl phthalate, dioctyl phthalate, In practicing this invention, the reaction phenyt acetate and tolyl acetate; hydrocarbons, temperature is not critical. In general, the such as dodecane, hexadecane, benzene, reaction temperature may be within the range naphthalene, and biphenyl; inorganic acid of 20°C-500°C, preferably 60°C-350°C, esters, such as triphenyl phosphate, tricresyl more preferably 89°C-250°C and most phosphate, dibutylphenyl phosphate, tetra- preferably 80°C-200°C. methyl ortho silicate, and tetrabutyl silicate; Ethylidene diacetate which is used as a raw aromatic ethers, such as diphenyl ether; and material in this invention may be prepared by ketones, such as acetone, methyl ethyl ketone, reacting acetaldehyde with acetic anhydride, or dibutyl ketone, methyl isobutyl ketone, aceto- by reduction reaction of acetic anhydride with phenone and benzophenone. hydrogen. Alternatively, ethylidene diacetate It is desirable in the present invention that the may be prepared by reacting dimethyl ether or concentration of vinyl acetate, which tends to methyl acetate with synthesis gas as disclosed cause polymerization, be maintained at a low in Japanese Patent Publication (Kokai) Nos. level by separating the vinyl acetate from the 62045/1980, 110647/1981. and 45884/1980 reaction system. For example, it is suitable to and British Patent No. 1,538,782. Acetalde- maintain the concentration of vinyl acetate in hyde, acetic anhydride, dimethyl ether, methyl the reaction system at less than 25 wt % by acetate, methyl iodide, etc. may be incor- continuously withdrawing (for example distill- porated in ethylidene diacetate prepared by ing) the resulting vinyl acetate from the reaction such methods. However, the ethylidene system and it is preferable to maintain the diacetate containing the components in such an concentration at less than 15 wt %. amount that the components are usually incor- Retention of large amount of the acetic acid, porated in ethylidene diacetate, that is the which is formed as a by-product in the reaction ethylidene diacetate containing small amount of system, should be avoided. The reason is that the components can be used as a raw material acetic acid tends to prevent formation of the in this invention. object product. So, in general, the concen- In general, water may be incorporated in the tration of acetic acid in the reaction system may reaction system.