JPS6236024B2 - - Google Patents
Info
- Publication number
- JPS6236024B2 JPS6236024B2 JP53068088A JP6808878A JPS6236024B2 JP S6236024 B2 JPS6236024 B2 JP S6236024B2 JP 53068088 A JP53068088 A JP 53068088A JP 6808878 A JP6808878 A JP 6808878A JP S6236024 B2 JPS6236024 B2 JP S6236024B2
- Authority
- JP
- Japan
- Prior art keywords
- rate
- exhaust gas
- concentration
- hydrogen
- methane
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 239000007789 gas Substances 0.000 claims description 62
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims description 54
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 claims description 48
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 claims description 44
- KKEYFWRCBNTPAC-UHFFFAOYSA-N Terephthalic acid Chemical compound OC(=O)C1=CC=C(C(O)=O)C=C1 KKEYFWRCBNTPAC-UHFFFAOYSA-N 0.000 claims description 32
- 239000001257 hydrogen Substances 0.000 claims description 32
- 229910052739 hydrogen Inorganic materials 0.000 claims description 32
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 30
- 238000006243 chemical reaction Methods 0.000 claims description 26
- 229910002092 carbon dioxide Inorganic materials 0.000 claims description 22
- 239000001569 carbon dioxide Substances 0.000 claims description 22
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 18
- 229910052799 carbon Inorganic materials 0.000 claims description 18
- 239000003054 catalyst Substances 0.000 claims description 18
- 238000004519 manufacturing process Methods 0.000 claims description 7
- 238000007254 oxidation reaction Methods 0.000 claims description 7
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 claims description 6
- XBDQKXXYIPTUBI-UHFFFAOYSA-M Propionate Chemical compound CCC([O-])=O XBDQKXXYIPTUBI-UHFFFAOYSA-M 0.000 claims description 6
- KXKVLQRXCPHEJC-UHFFFAOYSA-N acetic acid trimethyl ester Natural products COC(C)=O KXKVLQRXCPHEJC-UHFFFAOYSA-N 0.000 claims description 6
- 229910002091 carbon monoxide Inorganic materials 0.000 claims description 6
- -1 bromine compound Chemical class 0.000 claims description 4
- PQLVXDKIJBQVDF-UHFFFAOYSA-N acetic acid;hydrate Chemical compound O.CC(O)=O PQLVXDKIJBQVDF-UHFFFAOYSA-N 0.000 claims description 3
- 239000002904 solvent Substances 0.000 claims description 3
- GDTBXPJZTBHREO-UHFFFAOYSA-N bromine Substances BrBr GDTBXPJZTBHREO-UHFFFAOYSA-N 0.000 claims description 2
- 229910001385 heavy metal Inorganic materials 0.000 claims description 2
- 230000003647 oxidation Effects 0.000 claims description 2
- 229910052794 bromium Inorganic materials 0.000 claims 1
- URLKBWYHVLBVBO-UHFFFAOYSA-N Para-Xylene Chemical group CC1=CC=C(C)C=C1 URLKBWYHVLBVBO-UHFFFAOYSA-N 0.000 description 22
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 12
- 239000001301 oxygen Substances 0.000 description 12
- 229910052760 oxygen Inorganic materials 0.000 description 12
- GOUHYARYYWKXHS-UHFFFAOYSA-N 4-formylbenzoic acid Chemical compound OC(=O)C1=CC=C(C=O)C=C1 GOUHYARYYWKXHS-UHFFFAOYSA-N 0.000 description 11
- 238000000034 method Methods 0.000 description 10
- 238000002485 combustion reaction Methods 0.000 description 9
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 8
- 239000000203 mixture Substances 0.000 description 8
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 8
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 6
- 238000004040 coloring Methods 0.000 description 5
- 230000000052 comparative effect Effects 0.000 description 5
- 239000007800 oxidant agent Substances 0.000 description 5
- 229920000728 polyester Polymers 0.000 description 5
- 238000005259 measurement Methods 0.000 description 4
- 229910052757 nitrogen Inorganic materials 0.000 description 4
- JHJLBTNAGRQEKS-UHFFFAOYSA-M sodium bromide Chemical compound [Na+].[Br-] JHJLBTNAGRQEKS-UHFFFAOYSA-M 0.000 description 4
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 3
- 238000002425 crystallisation Methods 0.000 description 3
- 230000008025 crystallization Effects 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- CPELXLSAUQHCOX-UHFFFAOYSA-N Hydrogen bromide Chemical compound Br CPELXLSAUQHCOX-UHFFFAOYSA-N 0.000 description 2
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 2
- 230000004913 activation Effects 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 2
- ADCOVFLJGNWWNZ-UHFFFAOYSA-N antimony trioxide Chemical compound O=[Sb]O[Sb]=O ADCOVFLJGNWWNZ-UHFFFAOYSA-N 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 229910017052 cobalt Inorganic materials 0.000 description 2
- 239000010941 cobalt Substances 0.000 description 2
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 2
- 238000005886 esterification reaction Methods 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 238000006068 polycondensation reaction Methods 0.000 description 2
- 229920000139 polyethylene terephthalate Polymers 0.000 description 2
- 239000005020 polyethylene terephthalate Substances 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 238000010992 reflux Methods 0.000 description 2
- WKBOTKDWSSQWDR-UHFFFAOYSA-N Bromine atom Chemical class [Br] WKBOTKDWSSQWDR-UHFFFAOYSA-N 0.000 description 1
- 229910052684 Cerium Inorganic materials 0.000 description 1
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 1
- 238000002835 absorbance Methods 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 125000004432 carbon atom Chemical group C* 0.000 description 1
- 239000012159 carrier gas Substances 0.000 description 1
- 238000006555 catalytic reaction Methods 0.000 description 1
- ZMIGMASIKSOYAM-UHFFFAOYSA-N cerium Chemical compound [Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce] ZMIGMASIKSOYAM-UHFFFAOYSA-N 0.000 description 1
- 239000007806 chemical reaction intermediate Substances 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 239000011651 chromium Substances 0.000 description 1
- ZBYYWKJVSFHYJL-UHFFFAOYSA-L cobalt(2+);diacetate;tetrahydrate Chemical compound O.O.O.O.[Co+2].CC([O-])=O.CC([O-])=O ZBYYWKJVSFHYJL-UHFFFAOYSA-L 0.000 description 1
- BZRRQSJJPUGBAA-UHFFFAOYSA-L cobalt(ii) bromide Chemical compound Br[Co]Br BZRRQSJJPUGBAA-UHFFFAOYSA-L 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 230000002596 correlated effect Effects 0.000 description 1
- 230000000875 corresponding effect Effects 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000006378 damage Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 230000032050 esterification Effects 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 238000004868 gas analysis Methods 0.000 description 1
- 238000004817 gas chromatography Methods 0.000 description 1
- 239000001307 helium Substances 0.000 description 1
- 229910052734 helium Inorganic materials 0.000 description 1
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 1
- 150000002431 hydrogen Chemical class 0.000 description 1
- 229910000042 hydrogen bromide Inorganic materials 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 239000000543 intermediate Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 239000011572 manganese Substances 0.000 description 1
- 150000002697 manganese compounds Chemical class 0.000 description 1
- WPBNNNQJVZRUHP-UHFFFAOYSA-L manganese(2+);methyl n-[[2-(methoxycarbonylcarbamothioylamino)phenyl]carbamothioyl]carbamate;n-[2-(sulfidocarbothioylamino)ethyl]carbamodithioate Chemical compound [Mn+2].[S-]C(=S)NCCNC([S-])=S.COC(=O)NC(=S)NC1=CC=CC=C1NC(=S)NC(=O)OC WPBNNNQJVZRUHP-UHFFFAOYSA-L 0.000 description 1
- 238000004949 mass spectrometry Methods 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- HFPZCAJZSCWRBC-UHFFFAOYSA-N p-cymene Chemical compound CC(C)C1=CC=C(C)C=C1 HFPZCAJZSCWRBC-UHFFFAOYSA-N 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 238000006116 polymerization reaction Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 239000011541 reaction mixture Substances 0.000 description 1
- 230000009257 reactivity Effects 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
Landscapes
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Description
【発明の詳細な説明】
本発明は品質の一定した高純度テレフタル酸の
製造方法に関する。
ポリエステルをテレフタル酸（以下TAを略
す）とエチレングリコールから直接重合により製
造する方法が近年主として行われるようになつて
きたが、直接重合に用いる高純度TAのうち、特
別の精製工程を経ることなくパラジアルキルベン
ゼンの空気酸化反応だけで高純度TAを得る方法
に関しては、従来各種の方法が提案されている。
TAの純度については４−カルボキシベンズアル
デヒド（以下４−CBAと略す）の含有量とTAの
着色度が重要な項目であるが、着色度はポリエス
テルの色調に主要な影響を与えるものとして特に
重要であることが知られている。すなわち、TA
の着色度が低いほどそのTAより得られるポリエ
ステルの白度も高くなるわけであるが、一般に
TA着色度を低下させるに従つてTAの製造コス
トが上昇するので、経済的見地から適当なTA着
色度が選ばれている。ところが、TA着色度が変
動した場合には、ポリエステルの色調が変動し、
たとえばポリエステル繊維においては、色むらと
して現われるので、TAの着色度は一定であるこ
とが要求される。
しかるに、酸化反応だけで高純度TAを連続的
に製造する場合には、触媒濃度や原料、空気など
の流量の変動、反応器内部に付着するテレフタル
酸結晶塊、あるいは反応温度の変動などによつて
生成するTAの品質は直接影響を受け、わずかで
はあるが品質の変動が起こる。かかる品質変動の
原因は装置上の工夫によつて極力除去すべきであ
るのは言うまでもないが、TA品質の変動幅を小
さくしようとするほどその困難さが増大し、装置
や計測に要する費用の負担が、TAの不合格率の
低下による利益を上まわるようになつてくる。
一方、TAの品質変動を混合操作によつて抑制
する方法が考えられるが、TAは固体であるから
混合を行うには大きな貯蔵サイロ内での気流によ
る混合が必要となり、TA粒子の破壊等の好まし
くない現象が起こる。つまるところ、反応器で製
造されるTAの品質を一定にするような反応装置
ならびに反応方法が要求されていたのである。換
言すれば変動する反応条件のもとで生成するTA
の品質が一定となるようにコントロールするには
得られるべきTAの品質が早期に予測される必要
があるが、高温高圧下の不均一系反応であるTA
の品質の予測手段は従来見出されてはいなかつた
のである。
かかる観点から本発明者らは、速かに分析し得
る反応器排ガスの成分と、反応器生成物中のTA
品質の関係に注目し、検討を重ねた結果、反応器
の排ガス中の一酸化炭素、炭酸ガスおよび酢酸メ
チルから選ばれる一種以上のガス状炭素成分と、
水素またはメタンの濃度を連続的もしくは間歇的
に測定する装置を設けて排ガス中の酢酸および水
分を除外した乾燥排ガス中の該濃度を該装置によ
り測定し、反応温度、パラジアルキルベンゼン供
給速度、触媒濃度、空気供給速度および酢酸含水
率のうち少くとも一つを調節することにより、
(a) 排ガス中の水素またはメタンの濃度あるいは
水素またはメタンの発生速度ならびに
(b) ガス状炭素成分の発生速度のパラジアルキル
ベンゼン供給速度に対する割合
を一定に保つならば、製品として得られるTAの
着色度と４−CBA含有率を極めて一定にするこ
とができることを見出した。
本発明に適用できるパラジアルキルベンゼンと
は、パラシメン、パラキシレンおよびその酸化中
間体であるパラトルアルデヒドなどであり、重金
属触媒とはコバルト、マンガン、セリウム、ニツ
ケル、クロムなどの化合物であり、臭素化合物
は、分子状臭素、臭化水素、臭化ナトリウム、も
しくは臭化コバルトなどの形で使用される。特に
コバルト化合物およびマンガン化合物を触媒とし
て用い、反応温度190〜225℃でパラキシレンを空
気酸化すると有利である。
本発明に用いられる酸化剤である空気は、大気
組成の空気であつても、空気に若干量の不活性気
体が混合されていても、また酸素が混合されてい
てもよく、さらに反応器の排ガスが一部混合され
たものでもよい。要するに、反応器に導入される
酸化剤の70％以上が大気組成の空気であれば本発
明の方法は適用できる。
反応装置に設けるガス分析装置としては、ガス
クロマトグラフ法、質量分析法、赤外吸収法、紫
外吸収法、水素炎イオン化法、化学分析法などに
基づくガス分析装置が挙げられるが、各種の成分
を精密に測定するには、ガスクロマトグラフが有
用であり、自動的に作動するプロセスガスクロマ
トグラフが特に好ましい。
排ガス試料は、反応器の気相部から取つてもよ
いが、還流冷却器を通して酢酸と水の大部分を除
き、更に水洗して酢酸を除いた試料ガスを測定す
る方法が好ましい。
測定は連続であることが好ましいが、ガスクロ
マトグラフを使用する場合のように不連続的であ
つてもよい。ただし測定間隔は12時間以内、好ま
しくは４時間以内に１回の測定が行われるように
するのがよく、さらに好ましくは、反応器の平均
滞留時間よりも短い間隔で測定するのがよい。
排ガス成分の測定の好ましい実施態様は例によ
つて説明するが各成分のうちTAの４−CBA含有
率に強く相関するのは一酸化炭素、酢酸メチルま
たは炭酸ガスのガス状炭素成分、特に炭酸ガスの
発生速度のパラジアルキルベンゼン供給速度に対
する割合であり、特に好ましくは、炭酸ガス、一
酸化炭素および酢酸メチルの総計の発生速度のパ
ラジアルキルベンゼン供給速度に対する割合であ
る。かかる炭素含有ガスの発生速度は排ガスの流
速と排ガス中の炭酸含有ガス濃度から計算によつ
て求めることができるが、排ガスの流速が測定で
きない場合には次式により概算することができ、
いずれの方法でも本発明の目的を達成することが
できる。
排ガス流速（Ｎm2／Ｈ）＝供給空気流速×供給空気中の窒素濃度／排ガス中の窒素濃度 …(1)
従つて、たとえば酸化剤に大気組成の空気を用
い、パラキシレンを酸化する場合の炭酸ガス発生
速度のパラキシレン供給速度に対する割合、すな
わち炭酸ガス発生率は、つぎの(2)式で、排ガス中
の炭酸ガス濃度（CO2％）と窒素濃度（N2％）と
から計算される。
炭酸ガス発生率（モル炭酸ガス／モルパラキシレン）
＝ＣＯ２％×０．７８０３×空気供給速度（Ｎm3／Ｈ）×１０６／Ｎ２％×２２．４×パラキシレン供給速度（
Kg／Ｈ）…(2)
同様に、すべてのガス状炭素成分の発生率を燃
焼率と呼び、パラキシレンを空気酸化する場合に
は(3)式で計算される。
燃焼率（ｇ炭素原子／モルパラキシレン）
＝3.69×〔ＣＯ２（％）＋ＣＯ（％）＋３×ＣＨ３ＣＯ２ＣＨ３（％）／Ｎ２（％）×空気供給速度／パラキシ
レン供給速度…(3)
なお、本発明者らの検討によれば、(3)式のガス
状炭素成分がすべて溶媒酢酸の燃焼によつて生成
したものと考えて計算した酢酸原単位（燃焼率の
１／５．５３の数値に相当する）は、実際の酢酸原単位
に
比較的よく一致するので、経済性を評価するのに
便利であることが確認されている。
炭酸ガス以外の成分、たとえば一酸化炭素、酢
酸メチルの発生速度は、炭酸ガスのそれに比例的
である場合が多いので、炭酸ガスと同様に反応性
の指標に用いることが可能であるが、測定精度の
面から炭酸ガスを用いるのが好ましく、すべての
炭素成分を考慮した燃焼率を用いるのが、さらに
好ましい。
かかるガス状炭素成分の発生率は、反応条件に
よつて変化させることができるが、たとえば炭酸
ガスは(4)式によつて反応条件と関係づけられる。
炭酸ガス発生率＝Ａ・（Cat.）m（H2O）n（PAB）-1Exp（−Ea／RT） …(4)
Ａは比例定数、Cat.は触媒濃度、H2Oは酢酸含
水率、PABはパラジアルキルベンゼン供給速度
をあらわす。また次数ｍ，ｎはそれぞれ0.5〜1.0
−0.2〜−0.5であり、活性化エネルギーEaは15〜
30Kcal／molの値であり、これらＡ，ｍ，ｎおよ
びEaはそれぞれ反応装置、触媒組成およびパラ
ジアルキルベンゼンの種類などによつて固有の値
を持つている。
従つて、工業的にTAを製造する場合、その反
応装置、触媒組成などに固有の値を予め把握して
おくことにより、炭素成分の発生率を一定にする
よう反応条件を調節することが可能となる。
TAの4CBA含有率〔４−CBA〕は、炭素成分
発生率と(5)式のような相関関係にある。
〔４−CBA〕＝Ｂ・〔炭素成分発生率〕l …(5)
(5)式でＢは比例定数、次数ｌは−1.0〜−2.0の
値であり、反応方式に固有の定数である。
よつて、(4)式および(5)式により４−CBAを一
定にするよう炭素成分発生率を一定にする条件調
節が可能となる。なお、反応に供給される空気中
に炭素成分が含まれている場合には、その含有量
を、前述の方法によつて求めた排ガス中の炭素成
分の値から差し引くことが必要である。
つぎに、TAの着色度と重要な相関を持つもの
は、排ガス中の水素またはメタンの濃度あるいは
水素またはメタンの発生速度であることを見出し
た。すなわち、TA着色度は(6)式のように表わさ
れる。
Ｔ着色度＝K1〔水素発生速度〕P1
＝K2〔水素濃度〕P2＝K3〔メタン発生速度〕P
３
＝K4〔メタン濃度〕P4 …(6)
(6)式において、K1〜K4は比例定数であり、次
数P1〜P4は0.8〜15であつて、反応方法に固有の
値をとる。ただし(6)式において、水素もしくはメ
タンの濃度を用いることができるのは、酸化剤に
多量の反応排ガスを混合使用しない場合である。
(6)式における水素またはメタンの発生速度は、
(7)式のように計算される。
水素発生速度＝（排ガス中水素濃度−供給空気中水素濃度）×排ガス流速 …(7)
メタン発生速度も(7)式と同様に計算できる。
水素またはメタンの発生速度は(8)式によつて反
応条件と関係づけられる。
水素またはメタンの発生速度＝Ｄ・〔Ｃａｔ．〕ｑ〔Ｏ２〕ｒ〔ＰＡＢ〕ｓ〔Ｈ２Ｏ〕ｔ／Ｅｘｐ〔−Ｅａ／ＲＴ
〕…(8)
(8)式において、Ｄは比例定数、Cat.は触媒濃
度、O2は排ガス中の酸素濃度、PABはパラジア
ルキルベンゼン供給速度、H2Oは酢酸の含水率を
あらわす。またEaは活性エネルギをあらわし、
６〜15Kcal／molの値であり、次数ｑ，ｒ，ｓ，
ｔはそれぞれ−0.5〜−1.0，−0.7〜−1.3，0.5〜
1.5および0.1〜0.5の範囲にあり、これらＤ，
Ea，ｑ，ｒ，ｓおよびｔはそれぞれ反応装置や
触媒組成等による固有の値を取る。排ガス酸素濃
度とは、乾燥排ガス中の酸素濃度であり、空気供
給速度によつて調節することができる値である。
すなわち(8)式に従つて、反応温度、空気供給速
度、パラジアルキルベンゼン供給速度、酢酸含水
率もしくは触媒濃度のいずれか一条件または複数
の条件を微調節することにより、反応器排ガス分
析で求められる水素もくしはメタンの発生速度が
一定となるようにすれば、TA着色度を一定に保
つことができるのである。
つぎに、水素またはメタンの排ガス中の濃度
は、発生速度に比例するものではないが、比較的
せまい条件範囲であれば、実質的に発生速度と比
例するものと見なしうるので、水素またはメタン
の濃度もまた、(8)式に従うと考えてよいので、同
様の条件調節を行うことができる。
TAの4CBA含有率と炭素成分発生率あるいは
TA着色度と水素またはメタンの発生速度のかか
る相関関係がいかなる理由によるものかは不明で
あるが、炭素成分が酢酸溶媒の燃焼によつて発生
し、その燃焼反応と４−CBA酸化反応とが類似
の触媒反応であると考えて理由づけることもで
き、着色物質の生成は反応中間体ラジカルが酸素
不足の状態でカツプリングすることによつて生成
すると思われる一方、水素またはメタンの発生速
度は(8)式よりパラジアルキルベンゼンの供給速度
に対する活性触媒濃度の比率と反応系内の酸素分
圧とにより決定されていると考えられるので、着
色物質と水素またはメタンの発生も類似の要因に
支配されると推定される。
かかる推定によるならば、水素またはメタンの
濃度よりもそれらの発生速度の方がよりよくTA
の着色度と相関性を持つはずであり、事実発生速
度の方が濃度よりも若干よい相関係数を持つので
あるが、発生速度を知るためには排ガス流量を正
確に測定する必要があり、このようなことは煩雑
であるうえ、水素またはメタン濃度でも十分に
TA着色度を推定できるのである。ただし、酸化
剤として空気と反応器排ガスの混合ガスを用いる
ような場合には、混合ガスおよび排ガス中の水素
もしくはメタンの流量を測定し、酸化反応で発生
した水素もしくはメタンの発生速度を指標に用い
なければならないことは言うもでもない。
なお、水素とメタンはいずれを測定してもよい
が、ガスクロマトグラフで測定する場合は水素を
測定する方が、精度の面で好ましい。
TAの着色度は、４ｇのTAを２規定水酸化カ
リウム50mlに溶解し、光路長50mm、波長340nmに
おける吸光度で表わす。
以下に例を挙げて具体的に本発明を説明する。
なお、例中％はことわりがないかぎり重量％を意
味する。ただし、排ガス組成の％は容量％を意味
する。
実施例 １
容積28m3の反応器の排ガス還流冷却器の出口に
排ガス試料採取管を設け、試料ガスはラシヒリン
グを充てんしたカラムで水洗して酢酸を除去した
のち、プロセスガスクロマトグラフでヘリウムを
キヤリアガスとして、水素、酸素、窒素、メタ
ン、一酸化炭素および炭酸ガスを15分毎に分析記
録した。また２時間毎に別のガスクロマトグラフ
で上記成分の他に酢酸メチルをも分析した。別途
に排ガス酸素は磁気式分析計、炭酸ガスは赤外分
光式分析計にてそれぞれ連続的に分析記録した。
反応器にパラキシレンを1.3T／Ｈ、触媒とし
て酢酸コバルト四水塩0.135％、マンガン0.085％
および臭化ナトリウム0.107％を含む４％含水酢
酸を6.8T／Ｈの速度で供給し、空気を5800Nm3／
Ｈで吹き込み、反応温度215℃、反応圧力23Kg／
cm2、平均滞留時間１時間で酸化反応を行い、反応
器液面が一定になるよう190℃および10Kg／cm2に
保たれた第１結晶槽へ生成物を抜き出した。第１
結晶槽には約50Nm3／Ｈの速度で空気を導入し
た。第２、第３結晶槽を経て、テレフタル酸を分
離乾燥した。得られたテレフタル酸は２時間毎に
着色度および４−CBAを分析した。
テレフタル酸の製造を18日間続けたが、触媒濃
度が３％の巾で変動し、酢酸中の水分濃度も3.6
％から4.4％の変動を示したので、品質を一定に
するため、排ガス分析により燃焼率と排ガス中の
水素濃度が一定となるよう反応温度および空気供
給速度を微調整した。各条件の設定値、変動の標
準偏差および得られたテレフタル酸の品質ならび
に標準偏差を表１に示すが、着色度において変動
は極めて小さく、４−CBAの変動も満足すべき
値を示し製品テレフタル酸の不合格率は０であつ
た。
すなわち８時間ごとに得られたテレフタル酸と
エチレングリコールを重量比で100：45の割合で
反応器に仕込んで197℃の温度下にエステル化反
応を行ない、反応混合物が完全に均一化し、理論
量の水が留出したのを確認したのち、275℃の温
度下三酸化アンチモン触媒の存在下４時間重縮合
反応を行なつたところ、18日間で得られた54種類
のポリエチレンテレフタレート全てについて白度
が規格をパスした。
比較例 １
排ガスの精密な分析を行わず、単に磁気式酸素
分析計と赤外式炭酸ガス分析計のみを用いて、酸
素、炭酸ガス濃度を測定し、排ガスの中の酸素濃
度が一定になるよう空気供給量を微調整し、製品
テレフタル酸の分析値から反応温度を調整する操
作をくり返した以外は実施例１と同様の条件で14
日間運転した結果を表１に示す。この場合、触媒
濃度および酢酸中の水分濃度の変動は実施例１と
ほぼ同様であり、テレフタル酸品質の平均値もそ
れぞれ実施例１と同様であつたが、品質の変動は
着色度で約３倍、４−CBAで約２倍となり、製
品テレフタル酸の不合格率は５％に達した。すな
わち８時間ごとに得られたテレフタル酸を用いて
実施例１と同様の操作にしたがつてエステル化反
応と重縮合反応を行なつたところ、14日間で得ら
れた42種類のポリエチレンテレフタレートのうち
の２種類が白度の点で規格外となつた。
実施例２〜５比較例２〜５
実施例１と同様の反応条件で、例２はパラキシ
レン供給速度、例３は触媒濃度、例４は酢酸中の
水分含有率、例５は反応温度をそれぞれ別個に変
え、各条件で４日間づつ運転した。反応条件を変
える際は約６時間で条件変更が完了するようにし
た。この条件変更の期間中にも、テレフタル酸の
品質を一定に保つべく、排ガス分析計の水素濃
度、炭酸ガス発生率または燃焼率が一定となるよ
う指定した変更条件以外の反応条件を微調整し
た。結果を表１に示す。比較例２〜５は排ガス酸
素濃度を４％に調節する以外は、実施例２〜５に
対応する条件以外の条件の調整を行わなかつた場
合の２日間の品質の平均値および標準偏差値を表
わすものである。
実施例２〜５を通じて、大巾な条件変更を行つ
たにもかかわらずテレフタル酸の品質変動は小さ
く、製品の不合格率は16日間を通じて0.6％であ
つたが、比較例２〜５では製品TAの純度は満足
すべきものではあるが、それぞれの条件における
変動幅が大きく、比較例２〜５を通じてひとつの
工業製品として評価した場合には価値の低いもの
であつた。
【表】DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing high purity terephthalic acid of constant quality. In recent years, the method of producing polyester by direct polymerization from terephthalic acid (hereinafter abbreviated as TA) and ethylene glycol has become mainstream. Various methods have been proposed to obtain high-purity TA solely through the air oxidation reaction of para-dialkylbenzene.
Regarding the purity of TA, the content of 4-carboxybenzaldehyde (hereinafter abbreviated as 4-CBA) and the degree of coloration of TA are important items, but the degree of coloration is particularly important as it has a major influence on the color tone of polyester. It is known that there is. That is, T.A.
The lower the degree of coloration, the higher the whiteness of the polyester obtained from the TA, but in general
Since the production cost of TA increases as the degree of TA coloration is lowered, an appropriate degree of TA coloration is selected from an economic standpoint. However, when the degree of TA coloring changes, the color tone of polyester changes,
For example, in polyester fibers, the degree of coloring of TA is required to be constant because it appears as uneven coloring. However, when producing high-purity TA continuously by oxidation reaction alone, there are problems due to fluctuations in catalyst concentration, flow rates of raw materials, air, etc., terephthalic acid crystal clusters adhering to the inside of the reactor, and fluctuations in reaction temperature. The quality of the TA that is generated is directly affected, and slight variations in quality occur. It goes without saying that the causes of such quality fluctuations should be eliminated as much as possible by improving the equipment, but the more you try to reduce the range of fluctuations in TA quality, the more difficult it becomes, and the cost of equipment and measurement increases. The costs will begin to outweigh the benefits of lower TA failure rates. On the other hand, it is possible to suppress TA quality fluctuations by mixing operations, but since TA is a solid, mixing requires airflow in a large storage silo, which may cause destruction of TA particles, etc. An undesirable phenomenon occurs. In short, there was a need for a reaction device and a reaction method that would ensure constant quality of TA produced in the reactor. In other words, TA generated under varying reaction conditions
In order to control the quality of TA to be constant, it is necessary to predict the quality of TA at an early stage.
Until now, no means of predicting quality has been found. From this point of view, the present inventors discovered components of reactor exhaust gas that can be quickly analyzed and TA in reactor products.
As a result of careful consideration and repeated consideration of the quality relationship, we found that one or more gaseous carbon components selected from carbon monoxide, carbon dioxide, and methyl acetate in the exhaust gas of the reactor;
A device that continuously or intermittently measures the concentration of hydrogen or methane is installed, and the concentration in the dry exhaust gas, which excludes acetic acid and moisture in the exhaust gas, is measured using the device, and the reaction temperature, paradialkylbenzene supply rate, and catalyst concentration are determined. , the air supply rate, and the acetic acid water content to control (a) the concentration of hydrogen or methane in the exhaust gas or the generation rate of hydrogen or methane, and (b) the generation rate of gaseous carbon components. It has been found that if the ratio to paradialkylbenzene feed rate is kept constant, the degree of coloration and 4-CBA content of the TA obtained as a product can be kept very constant. Para-dialkylbenzenes that can be applied to the present invention include paracymene, para-xylene, and their oxidized intermediate para-toaldehyde, heavy metal catalysts include compounds such as cobalt, manganese, cerium, nickel, and chromium, and bromine compounds include , molecular bromine, hydrogen bromide, sodium bromide, or cobalt bromide. Particularly advantageous is the air oxidation of paraxylene using cobalt and manganese compounds as catalysts at a reaction temperature of 190 DEG to 225 DEG C. The air that is the oxidizing agent used in the present invention may be air of atmospheric composition, a small amount of inert gas mixed with the air, or oxygen mixed with the air. A mixture of exhaust gases may also be used. In short, the method of the present invention can be applied if 70% or more of the oxidizing agent introduced into the reactor is air of atmospheric composition. Examples of gas analyzers installed in the reactor include gas analyzers based on gas chromatography, mass spectrometry, infrared absorption, ultraviolet absorption, flame ionization, chemical analysis, etc. For precise measurements, gas chromatographs are useful, and automatically operated process gas chromatographs are particularly preferred. The exhaust gas sample may be taken from the gas phase of the reactor, but it is preferable to remove most of the acetic acid and water through a reflux condenser and then wash the sample gas with water to remove the acetic acid and then measure the sample gas. The measurements are preferably continuous, but may also be discontinuous, such as when using a gas chromatograph. However, the measurement interval is preferably within 12 hours, preferably within 4 hours, and more preferably at intervals shorter than the average residence time of the reactor. Preferred embodiments for measuring exhaust gas components will be explained using examples, but among the components, gaseous carbon components such as carbon monoxide, methyl acetate, or carbon dioxide, particularly carbon dioxide, are strongly correlated with the 4-CBA content of TA. It is the ratio of the gas generation rate to the para-dialkylbenzene supply rate, particularly preferably the ratio of the total generation rate of carbon dioxide, carbon monoxide and methyl acetate to the para-dialkylbenzene supply rate. The rate of generation of such carbon-containing gas can be calculated from the flow rate of the exhaust gas and the concentration of carbon dioxide-containing gas in the exhaust gas, but if the flow rate of the exhaust gas cannot be measured, it can be roughly estimated using the following formula:
Either method can achieve the object of the present invention. Exhaust gas flow rate (Nm 2 /H) = Supply air flow rate × Nitrogen concentration in supplied air / Nitrogen concentration in exhaust gas ... (1) Therefore, for example, when paraxylene is oxidized using air with atmospheric composition as an oxidizing agent, The ratio of the carbon dioxide gas generation rate to the paraxylene supply rate, that is, the carbon dioxide gas generation rate, is calculated from the carbon dioxide concentration (CO 2 %) and nitrogen concentration (N 2 %) in the exhaust gas using the following equation (2). Ru. Carbon dioxide generation rate (mole carbon dioxide/mole para-xylene) = CO 2 % × 0.7803 × air supply rate (Nm 3 /H) × 106/N 2 % × 22.4 × para-xylene supply rate (
Kg/H)...(2) Similarly, the generation rate of all gaseous carbon components is called the combustion rate, and when paraxylene is air oxidized, it is calculated using equation (3). Combustion rate (g carbon atoms/mole para-xylene) = 3.69 x [CO 2 (%) + CO (%) + 3 x CH 3 CO 2 CH 3 (%) / N 2 (%) x air supply rate / para-xylene supply rate ...(3) According to the studies of the present inventors, the acetic acid basic unit (1 of the combustion rate) calculated assuming that all the gaseous carbon components in equation (3) are generated by combustion of the solvent acetic acid. /5.53) corresponds relatively well to the actual acetic acid consumption rate, and has been confirmed to be convenient for evaluating economic efficiency. The rate of generation of components other than carbon dioxide, such as carbon monoxide and methyl acetate, is often proportional to that of carbon dioxide, so they can be used as indicators of reactivity in the same way as carbon dioxide; however, they cannot be measured. From the viewpoint of accuracy, it is preferable to use carbon dioxide gas, and it is more preferable to use a combustion rate that takes into account all carbon components. The generation rate of such a gaseous carbon component can be changed depending on the reaction conditions; for example, carbon dioxide gas is related to the reaction conditions by equation (4). Carbon dioxide generation rate = A・(Cat.) m (H 2 O) n (PAB) -1 Exp (-Ea/RT) ...(4) A is proportionality constant, Cat. is catalyst concentration, H 2 O is acetic acid Moisture content and PAB represent paradialkylbenzene supply rate. Also, the orders m and n are each 0.5 to 1.0
−0.2 to −0.5, and activation energy Ea is 15 to
The value is 30 Kcal/mol, and these A, m, n, and Ea each have specific values depending on the reactor, catalyst composition, type of paradialkylbenzene, etc. Therefore, when manufacturing TA industrially, by understanding the specific values of the reaction equipment, catalyst composition, etc. in advance, it is possible to adjust the reaction conditions to keep the generation rate of carbon components constant. becomes. The 4CBA content [4-CBA] of TA has a correlation with the carbon component generation rate as shown in equation (5). [4-CBA] = B・[Carbon component generation rate] l ...(5) In equation (5), B is a proportionality constant, and the order l is a value between -1.0 and -2.0, which is a constant specific to the reaction method. . Therefore, by equations (4) and (5), it is possible to adjust the conditions to keep the carbon component generation rate constant so as to keep 4-CBA constant. In addition, when a carbon component is contained in the air supplied to the reaction, it is necessary to subtract the content from the value of the carbon component in the exhaust gas determined by the above-mentioned method. Next, we found that the concentration of hydrogen or methane in the exhaust gas or the generation rate of hydrogen or methane had an important correlation with the degree of coloration of TA. That is, the TA coloring degree is expressed as in equation (6). T coloring degree = K 1 [Hydrogen generation rate] P1 = K 2 [Hydrogen concentration] P2 = K 3 [Methane generation rate] P
3 = K 4 [Methane concentration] P4 ...(6) In equation (6), K 1 to K 4 are proportional constants, and the orders P 1 to P 4 are 0.8 to 15 and are values specific to the reaction method. Take. However, in equation (6), the concentration of hydrogen or methane can be used when a large amount of reaction exhaust gas is not mixed with the oxidizing agent. The generation rate of hydrogen or methane in equation (6) is
It is calculated as in equation (7). Hydrogen generation rate = (hydrogen concentration in exhaust gas - hydrogen concentration in supplied air) x exhaust gas flow rate...(7) The methane generation rate can also be calculated in the same way as equation (7). The rate of hydrogen or methane generation is related to reaction conditions by equation (8). Generation rate of hydrogen or methane = D [Cat. ] q [O 2 ] r [PAB] s [H 2 O] t /Exp [-Ea/RT
]...(8) In formula (8), D is a proportionality constant, Cat. is the catalyst concentration, O 2 is the oxygen concentration in the exhaust gas, PAB is the paradialkylbenzene supply rate, and H 2 O is the water content of acetic acid. Also, Ea represents activation energy,
The value is 6 to 15 Kcal/mol, and the orders q, r, s,
t is -0.5 to -1.0, -0.7 to -1.3, 0.5 to respectively
1.5 and in the range of 0.1 to 0.5, and these D,
Ea, q, r, s and t each take a unique value depending on the reactor, catalyst composition, etc. The exhaust gas oxygen concentration is the oxygen concentration in the dry exhaust gas, and is a value that can be adjusted by adjusting the air supply rate. In other words, according to equation (8), by finely adjusting one or more of the following conditions: reaction temperature, air supply rate, paradialkylbenzene supply rate, acetic acid water content, or catalyst concentration, the By keeping the rate of methane generation constant in the hydrogen comb, the degree of TA coloration can be kept constant. Next, although the concentration of hydrogen or methane in exhaust gas is not proportional to the generation rate, it can be considered to be substantially proportional to the generation rate in a relatively narrow range of conditions. Since the concentration can also be considered to follow equation (8), similar conditions can be adjusted. 4CBA content of TA and carbon component generation rate or
The reason for this correlation between the degree of TA coloration and the generation rate of hydrogen or methane is unknown, but it is likely that the carbon component is generated by the combustion of the acetic acid solvent, and that the combustion reaction and the 4-CBA oxidation reaction are linked. It can be reasoned that it is a similar catalytic reaction, and the production of colored substances is thought to be due to the coupling of reaction intermediate radicals in oxygen-deficient conditions, while the rate of generation of hydrogen or methane is ( From equation 8), it is thought that it is determined by the ratio of the active catalyst concentration to the supply rate of paradialkylbenzene and the oxygen partial pressure in the reaction system, so the generation of colored substances and hydrogen or methane is also controlled by similar factors. It is estimated to be. According to such an estimate, the rate of generation of hydrogen or methane is a better predictor of TA than the concentration of hydrogen or methane.
There should be a correlation with the degree of coloration, and in fact, the rate of generation has a slightly better correlation coefficient than the concentration, but in order to know the rate of generation, it is necessary to accurately measure the exhaust gas flow rate. This is complicated, and even hydrogen or methane concentrations are insufficient.
It is possible to estimate the degree of TA coloration. However, when using a mixed gas of air and reactor exhaust gas as the oxidizing agent, measure the flow rate of hydrogen or methane in the mixed gas and exhaust gas, and use the generation rate of hydrogen or methane generated in the oxidation reaction as an index. Needless to say, it must be used. Note that although either hydrogen or methane may be measured, when measuring with a gas chromatograph, it is preferable to measure hydrogen in terms of accuracy. The degree of coloration of TA is expressed by dissolving 4 g of TA in 50 ml of 2N potassium hydroxide and measuring the absorbance at a wavelength of 340 nm and an optical path length of 50 mm. The present invention will be specifically described below with reference to examples.
In addition, % in the examples means weight % unless otherwise specified. However, % of exhaust gas composition means volume %. Example 1 An exhaust gas sampling tube was installed at the outlet of the exhaust gas reflux condenser of a reactor with a volume of 28 m 3 , and the sample gas was washed with water in a column filled with a Raschig ring to remove acetic acid, and then helium was used as a carrier gas in a process gas chromatograph. , hydrogen, oxygen, nitrogen, methane, carbon monoxide and carbon dioxide were analyzed and recorded every 15 minutes. In addition to the above components, methyl acetate was also analyzed every 2 hours using a separate gas chromatograph. Separately, exhaust gas oxygen was continuously analyzed and recorded using a magnetic analyzer and carbon dioxide gas using an infrared spectrometer. 1.3T/H of paraxylene in the reactor, cobalt acetate tetrahydrate 0.135%, manganese 0.085% as catalyst
and 4% hydrous acetic acid containing 0.107% sodium bromide were supplied at a rate of 6.8T/H, and air was supplied at a rate of 5800Nm 3 / H.
Blow with H, reaction temperature 215℃, reaction pressure 23Kg/
The oxidation reaction was carried out at an average residence time of 1 hour, and the product was extracted into a first crystallization tank maintained at 190° C. and 10 kg/cm 2 so that the liquid level in the reactor remained constant . 1st
Air was introduced into the crystallization tank at a rate of about 50 Nm 3 /H. The terephthalic acid was separated and dried through the second and third crystallization tanks. The obtained terephthalic acid was analyzed for coloration degree and 4-CBA every 2 hours. Terephthalic acid production continued for 18 days, but the catalyst concentration fluctuated within a range of 3%, and the water concentration in acetic acid also decreased to 3.6%.
% to 4.4%, so in order to keep the quality constant, the reaction temperature and air supply rate were finely adjusted by exhaust gas analysis so that the combustion rate and hydrogen concentration in the exhaust gas remained constant. Table 1 shows the set values for each condition, the standard deviation of the fluctuations, and the quality and standard deviation of the obtained terephthalic acid. The rejection rate of acid was 0. That is, the obtained terephthalic acid and ethylene glycol were charged into a reactor at a weight ratio of 100:45 every 8 hours, and the esterification reaction was carried out at a temperature of 197°C. The reaction mixture was completely homogenized and the theoretical amount After confirming that water had distilled out, a polycondensation reaction was carried out for 4 hours in the presence of an antimony trioxide catalyst at a temperature of 275°C, and the whiteness of all 54 types of polyethylene terephthalate obtained in 18 days was passed the standard. Comparative Example 1 Oxygen and carbon dioxide concentrations are measured simply using a magnetic oxygen analyzer and an infrared carbon dioxide analyzer without conducting a precise analysis of the exhaust gas, and the oxygen concentration in the exhaust gas becomes constant. 14 under the same conditions as in Example 1, except that the air supply amount was finely adjusted and the reaction temperature was adjusted based on the analytical value of the product terephthalic acid.
Table 1 shows the results of one day's operation. In this case, the fluctuations in the catalyst concentration and the water concentration in acetic acid were almost the same as in Example 1, and the average value of the quality of terephthalic acid was also the same as in Example 1, but the fluctuation in quality was about 3 in terms of degree of coloration. 4-CBA, the rejection rate of the product terephthalic acid reached 5%. That is, when esterification and polycondensation reactions were carried out in the same manner as in Example 1 using terephthalic acid obtained every 8 hours, out of 42 types of polyethylene terephthalate obtained in 14 days. Two types were outside the standard in terms of whiteness. Examples 2 to 5 Comparative Examples 2 to 5 The same reaction conditions as Example 1 were used, with the para-xylene feed rate in Example 2, the catalyst concentration in Example 3, the water content in acetic acid in Example 4, and the reaction temperature in Example 5. Each condition was changed separately, and each condition was operated for 4 days. When changing the reaction conditions, the change of conditions was completed in about 6 hours. In order to maintain the quality of terephthalic acid at a constant level even during this period of changing conditions, we fine-tuned the reaction conditions other than the specified change conditions so that the hydrogen concentration, carbon dioxide generation rate, or combustion rate on the exhaust gas analyzer remained constant. . The results are shown in Table 1. Comparative Examples 2 to 5 are the average values and standard deviation values of the quality for two days when no conditions other than those corresponding to Examples 2 to 5 are adjusted except for adjusting the exhaust gas oxygen concentration to 4%. It represents. Throughout Examples 2 to 5, despite extensive changes in conditions, the quality of terephthalic acid varied little, and the product rejection rate was 0.6% over 16 days; however, in Comparative Examples 2 to 5, the product Although the purity of TA was satisfactory, the range of variation under each condition was large, and when evaluated as an industrial product through Comparative Examples 2 to 5, it was of low value. 【table】
Claims (1)
臭素化合物の存在下に酢酸溶媒中で空気酸化して
テレフタル酸を製造する方法において、反応器の
排ガス中の一酸化炭素、炭酸ガスおよび酢酸メチ
ルから選ばれる一種以上のガス状炭素成分と、水
素またはメタンの濃度を連続的もしくは間歇的に
測定する装置を設けて排ガス中の酢酸および水分
を除外した乾燥排ガス中の該濃度を該装置により
測定し、反応温度、パラジアルキルベンゼン供給
速度、触媒濃度、空気供給速度および酢酸含水率
のうち少くとも一つを調節することにより、 (a) 排ガス中の水素またはメタンの濃度あるいは
水素またはメタンの発生速度ならびに (b) ガス状炭素成分の発生速度のパラジアルキル
ベンゼン供給速度に対する割合 を一定に保つことを特徴とする品質の一定した高
純度テレフタル酸の製造方法。[Claims] 1. In a method for producing terephthalic acid by air oxidation of para-dialkylbenzene in an acetic acid solvent in the presence of a heavy metal catalyst and a bromine compound, carbon monoxide, carbon dioxide gas and methyl acetate in the exhaust gas of a reactor are A device is provided to continuously or intermittently measure the concentration of one or more gaseous carbon components selected from hydrogen or methane, and the concentration in the dry exhaust gas excluding acetic acid and moisture in the exhaust gas is measured by the device. By adjusting at least one of the reaction temperature, paradialkylbenzene supply rate, catalyst concentration, air supply rate, and acetic acid water content, (a) the concentration of hydrogen or methane in the exhaust gas or the generation rate of hydrogen or methane; and (b) a method for producing high-purity terephthalic acid of constant quality, characterized in that the ratio of the gaseous carbon component generation rate to the paradialkylbenzene supply rate is kept constant.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6808878A JPS54160330A (en) | 1978-06-05 | 1978-06-05 | Preparation of high-purity terephthalic acid of stable quality |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6808878A JPS54160330A (en) | 1978-06-05 | 1978-06-05 | Preparation of high-purity terephthalic acid of stable quality |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS54160330A JPS54160330A (en) | 1979-12-19 |
| JPS6236024B2 true JPS6236024B2 (en) | 1987-08-05 |
Family
ID=13363625
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP6808878A Granted JPS54160330A (en) | 1978-06-05 | 1978-06-05 | Preparation of high-purity terephthalic acid of stable quality |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS54160330A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4835307A (en) * | 1984-12-13 | 1989-05-30 | Amoco Corporation | Method and apparatus for controlling the manufacture of terephthalic acid to control the level and variability of the contaminant content and the optical density |
| JPH10287613A (en) * | 1997-02-12 | 1998-10-27 | Mitsui Chem Inc | Quality control of terephthalic acid |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS51127037A (en) * | 1975-04-11 | 1976-11-05 | Ici Ltd | Continuous production of telephthalic acid |
| JPS5334738A (en) * | 1976-09-09 | 1978-03-31 | Toray Ind Inc | Continuous preparation of terephthalic acid |
-
1978
- 1978-06-05 JP JP6808878A patent/JPS54160330A/en active Granted
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS51127037A (en) * | 1975-04-11 | 1976-11-05 | Ici Ltd | Continuous production of telephthalic acid |
| JPS5334738A (en) * | 1976-09-09 | 1978-03-31 | Toray Ind Inc | Continuous preparation of terephthalic acid |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS54160330A (en) | 1979-12-19 |
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