Samsung General Chemicals, Co., Ltd.

Samsung General Chemical Co., Ltd.

Youn-Seok Park

Sung-Hwa Jhung

Jin S Yoo

Ki-Hwa Lee

Chun-Byung Yang

Ki-Su Ro

Il-Seop Kim

Gap-goung Kong

Jong-Hyun Chae

An improved production method of aromatic carboxylic acid products of significantly improved yield and quality by oxidizing alkyl aromatic substrates or their partially oxidized intermediates in a conventional MC-type catalyst system modified to contain additional components such as alkali metal or alkaline earth metal in an acetic acid medium in a feed gas containing oxygen and optionally carbon dioxide. Since carbon dioxide functioned as a co-oxidant along with oxygen in the oxidation reaction, the oxidation reaction proceeds more selectively to produce the carboxylic acid product much faster under milder reaction conditions over the conventional MC-type oxidation. In particular, the oxidation of para-xylene carried out by the novel present method enabled production of terephthalic acid of higher yield and enhanced quality, which were improved far more than the extent that generally could be expected by current PTA producers. The present invention also provides an effective purification process to produce highly pure terephthalic acid or isophthalic acid by the oxidation of impurities such as 4-carboxybenzaldehyde and para-toluic acid or 3-carboxybenzaldehyde and meta-toluic acid contaminated in crude terephthalic acid and isophthalic acid product, respectively.

Method of producing aromatic carboxylic acids by oxidizing alkyl aromatic hydrocarbons or partially oxidized intermediates thereof

An improved production method of aromatic carboxylic acid products of significantly improved yield and quality, the method including oxidizing alkyl aromatic substrates or their partially oxidized intermediates in a catalyst system containing a conventional catalyst and, if deemed necessary, additional components such as a transition metal or lanthanide series metal, in an acetic acid medium, with a feed gas containing both oxygen and carbon dioxide. Since carbon dioxide functions as a co-oxidant along with oxygen in the oxidation reaction, the oxidation reaction proceeds more selectively to produce the carboxylic acid product much faster under milder reaction conditions as compared to the conventional oxidation. The present invention also can be utilized as an effective purification process to produce highly pure terephthalic acid or isophthalic acid by oxidation of impurities such as 4-carboxybenzaldehyde and para-toluic acid or 3-carboxybenzaldehyde and meta-toluic acid which are contaminated in crude terephthalic acid and isophthalic acid products, respectively.

Method of producing aromatic carboxylic acids by oxidizing alkyl aromatic compounds or partially oxidized intermediates thereof with carbon dioxide containing gas

An improved production method of aromatic carboxylic acids of significantly improved yields and quality by oxidizing alkyl aromatic substrates or their partially oxidized intermediates by oxygen-enriched gas in a conventional Co&mdash;Mn&mdash;Br catalyst system containing additional components such as a transition metal or lanthanide metal component in an aliphatic carboxylic acid having 1&tilde;6 carbon atoms. In other words, a decline in reactivity in the later part of the oxidation reaction and the precipitation of a catalyst such as manganese were effectively deterred by means of incorporating one or more than one type of transition or lanthanide metal components selected from such metals as Ce, Zr, Hf, Fe, Cr, and Mo during the oxidation reaction with oxygen-enriched gas. With this invention, pure aromatic carboxylic acids with white color can be obtained with high selectivity and reactivity by oxidation of substrates with oxygen-enriched gas. The oxidation reaction of alkylaromatic substrates proceeds more selectively with a much faster rate to produce aromatic carboxylic acids of improved quality as compared to those of conventional oxidation processes.

Method of producing aromatic carboxylic acids by oxidizing alkyl aromatic compounds or partially oxidized intermediates thereof with oxygen-enriched gas

A method for polymerization or copolymerization of .alpha.-olefin, characterized in that the polymerization is performed using a solid complex titanium catalyst comprising magnesium, a halogen-containing titanium compound, and internal electron donors; organometallic compounds of metals belonging to Groups I and III on the periodic table of elements; and, as external electron donors, a mixture of three or more kinds of organic silicon compounds, from which homopolyolefins having MFR less than 5, MFR in the range from 5 to 20, and MFR greater than 20 are polymerized under the same polymerization conditions. By use of the present invention it is possible to produce an olefin polymer with high stereoregularity, broad molecular weight distribution, and good fluidity, at high rates of yield.

Method for polymerization of an .alpha.-olefin

A catalyst for olefin (co)polymerization, comprising a solid catalyst component employing chelated transition metal compound supported on inorganic magnesium compound and organoaluminum compound; and a process for olefin (co)polymerization using the catalyst.

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Taejeon-shi, South Korea

Youn-Seok Park