CS247586B1

CS247586B1 - A method of neutralizing waste hydrochloric acid from the production of 3-methyl-4-nitrophenol

Info

Publication number: CS247586B1
Application number: CS547985A
Authority: CS
Inventors: Peter Hauskrecht
Original assignee: Peter Hauskrecht
Priority date: 1985-07-25
Filing date: 1985-07-25
Publication date: 1987-01-15

Abstract

Odpadni kyselina chlorovodíková z výroby 3-metyl-4-nitrofenolu sa zneutralizuje odpadnými kalmi hydroxidu vápennaténo z výroby 2-merkaptobenztiazolu na hodnotu pil 2 az ], s výhodou 3 až ů. Po neutralizácii nerozpustné látky se oddelia, s výhodou sedimentáciou. Získaný roztok je možné vypúšíaí do cher.rickej kanalizácie. nerozpustné látky sa r.ióžu uskladnit na skládke chemických odpadov.Waste hydrochloric acid from the production of 3-methyl-4-nitrophenol is neutralized with waste calcium hydroxide sludge from the production of 2-mercaptobenzothiazole to a pH value of 2 to 1, preferably 3 to 3. After neutralization, insoluble substances are separated, preferably by sedimentation. The obtained solution can be discharged into the municipal sewage system. Insoluble substances can be stored in a chemical waste landfill.

Description

Vynález sa týká neutralizácie odpadnej kyseliny chlorovodíkovéj vznikajúcej pri výrobě 3-metyl-4-nitrofenolu.The invention relates to the neutralization of waste hydrochloric acid resulting from the production of 3-methyl-4-nitrophenol.

3-metyl-4-nitrofenol sa vyrába nitrozáciou 3-metylfenolu s dusitanom sodným v přítomnosti minerálnej kyseliny a následnou oxidáciou vzniklého 3-metyl-4-nitrózofenolu na 3-metyl-4-nitrofenol s kyselinou dusičnou. Zo suspenzie sa 3-metyl-4-nitrofenol· odfiltruje. Ako odpad vzniká roztok minerálnej kyseliny, najčastejšie kyseliny sírovej alebo chlorovodíkovej. Odpadná kyselina chlorovodíková obsahuje ako nečistoty chlorid sodný, 3-metylfenol a jeho nitro-, nitrózoderiváty, kyselinu dusičná, kyselinu dusitá. Obsah HCl je pod 10 % hmotnosti. Vzhladom na obsah nečistót sa kyselina chlorovodíková najčastejšie neutralizuje a vypášta do odpadných vod.3-Methyl-4-nitrophenol is produced by nitrosation of 3-methylphenol with sodium nitrite in the presence of a mineral acid and subsequent oxidation of the resulting 3-methyl-4-nitrosophenol to 3-methyl-4-nitrophenol with nitric acid. The 3-methyl-4-nitrophenol is filtered from the suspension. The waste is a mineral acid solution, most often sulfuric acid or hydrochloric acid. Waste hydrochloric acid contains as impurities sodium chloride, 3-methylphenol and its nitro, nitroso derivatives, nitric acid, nitrous acid. The HCl content is below 10% by weight. Due to the impurity content, hydrochloric acid is most often neutralized and discharged into waste water.

2-merkaptobenztiazol /kaptax/ sa vyrába kondenzáciou anilínu, síry a sírouhlíka. Surový kaptax sa čistí hydroxidom vápenatým, pričom odpadajá vápenaté kaly, které obsahujá okrem hydroxidu vápenatého vápenatá sol kaptaxu, nerozpustné smolovité látky a nečistoty z použitého hydroxidu vápenatého. Vzniklé kaly sa skladujá na skládke chemického odpadu.2-mercaptobenzothiazole (captax) is produced by condensation of aniline, sulfur and carbon disulphide. The crude captax is cleaned with calcium hydroxide, leaving out the calcium sludge which contains, in addition to calcium hydroxide, the calcium salt of captax, insoluble pitches and impurities from the calcium hydroxide used. The resulting sludge is stored in a chemical waste dump.

Vyššie uvedené nedostatky sá odstránené spósobom neutralizácie odpadnej kyseliny chlorovodíkovej z výroby 3-metyl-4-nitrofenolu, podstata ktorého spočívá v tom, že sa kyselina chlorovodíková neutralizuje s odpadným hydroxidom vápenatým z výroby kaptaxu. Odpadná kyselina chlorovodíková obsahuje ako nečistoty chlorid sodný, 3-metylfenol a jeho nitro-, a nitrózo-deriváty, kyselinu dusičná, kyselinu dusitá. Odpadný hydroxid vápennatý obsahuje 3 až 50 % hmotnosti hydroxidu vápennatého, 0,1 až 5 % hmotnosti vápennatej soli kaptaxu, až 20 % hmotnosti smolovitých látok, ktoré vznikajá ako vedlajšie produkty pri výrobě kaptaxu a nečistoty z technického hydroxidu vápenatého.The aforementioned drawbacks are eliminated by the method of neutralizing waste hydrochloric acid from the production of 3-methyl-4-nitrophenol, which consists in neutralizing the hydrochloric acid with the waste calcium hydroxide from the production of captax. Waste hydrochloric acid contains as impurities sodium chloride, 3-methylphenol and its nitro- and nitroso-derivatives, nitric acid, nitrous acid. The waste calcium hydroxide contains 3 to 50% by weight of calcium hydroxide, 0.1 to 5% by weight of calcium salt of captax, up to 20% by weight of pitch substances which are formed as byproducts in the manufacture of captaxa and impurities from technical calcium hydroxide.

Výsledná hodnota pH je 2 až 7, s výhodou 3 až 6. Z reakčnej zmesi sa vyzrážajá ako nečistoty kaptax, smolovité látky, 3-metyl-4-nitrofenol a nečistoty z technického hydroxidu vápennatého, predovšetkým kremičitany. Vyzrážané nečistoty sa oddelia s výhodou sedimentáciou a získaný roztok sa móže vypustiť do odpadných vod.The resulting pH is 2 to 7, preferably 3 to 6. The reaction mixture precipitates as impurities impurities, pitches, 3-methyl-4-nitrophenol and impurities from industrial calcium hydroxide, in particular silicates. The precipitated impurities are preferably separated by sedimentation and the resulting solution can be discharged into waste water.

Výhodou, podlá vynálezu je, že sa použije na neutralizáciu odpadný hydroxid vápenatý, ktorý sa doteraz nevyužívá a skladuje sa nákladné na skládke chemických odpadov. Pri neutralizácii sa na ňu využije z vápenatých kalov hydroxid vápennatý a vápennatá sol kaptaxu. Vápennaté ióny přejdu vo formě chloridu do roztoku. Ako nerozpustné látky sa vyzrážajá predovšetkým časť 3-metyl-4-nitrofenolu, kaptax, smolovité látky a kremičitany.An advantage according to the invention is that waste calcium hydroxide is used for neutralization, which has not been used up to now and is stored expensive in a chemical waste dump. In the case of neutralization, calcium hydroxide and the calcium salt of captax are used for this purpose. The calcium ions go into solution as chloride. Particularly 3-methyl-4-nitrophenol, captax, pitch and silicates are precipitated as insoluble materials.

Vyzrážané látky- sa oddelia s výhodou sedimentáciou. Kal možno po úpravě skladovat na skládke chemických odpadov. Objem vzniklého kalu je o mnoho menší ako objem póvodných vápennatých kalov z výroby kaptaxu. Na neutralizáciu sa použije miesto hydroxidu vápennatého alebo sodného prakticky odpadný hydroxid vápennatý, ktorý sa nevyužívá a so skladováním na skládke chemických odpadov su problémy a vznikajá náklady na jeho uskladnenie.The precipitated substances are preferably separated by sedimentation. After treatment, the sludge can be stored in a chemical waste dump. The volume of the resulting sludge is much smaller than the volume of the original lime sludge from the production of captax. For neutralization, virtually waste calcium hydroxide is used instead of calcium or sodium hydroxide, which is not used and has problems in storing in a chemical waste dump and incurs storage costs.

PřikladlEXAMPLE

Do banky sa dalo 500 ml odpadnej kyseliny chlorovodíkovej, ktorá obsahovala 10,2 % hmotnosti HCl, 3,1 % hmotnosti NaCl, 1 720 mq/1 3-metyl-4-nitrofenolu, 240 mg/1 3-mety1fenolu, 0,9 % hmotnosti HNO^, a 0,04 % hmotnosti HNO₂ . Ku kyselině sa přidala suspenzia vápenných kalov z výroby kaptaxu, ktorá obsahovala 5,2 % hmotnosti Ca/OH/₂, 0,4 %. hmotnosti vápennatej soli kaptaxu a 2,1 % hmotnosti smolovitých látok. Zmes sa zneutralizovala na hodnotu pH 3,4. Nerozpustné látky sa odfiltrovali. Filtrát raal hodnotu pH 3,4.The flask was charged with 500 mL of waste hydrochloric acid containing 10.2 wt% HCl, 3.1 wt% NaCl, 1,720 mq / l 3-methyl-4-nitrophenol, 240 mg / l 3-methylphenol, 0.9 and 0.04% by weight of HNO ₂ . To the acid was added a slurry of lime sludge from the manufacture of captaxa which contained 5.2% by weight Ca / OH / ₂ , 0.4%. by weight of captax calcium salt and 2.1% by weight of pitch substances. The mixture was neutralized to pH 3.4. Insoluble materials were filtered off. The filtrate had a pH of 3.4.

Příklad 2Example 2

Postupovalo sa podlá příkladu 1 s tým rozdielom, že sa na neutralizáciu použili vápenaté kaly, ktoré obsahovali 41 % hmotnosti hydroxidu vápenatého, 3,8 % vápennatej soli kaptaxu a 13,1 % hmotnosti smolovitých látok. Hodnota pH po neutralizácii bola 6,5. Nerozpustné látky sa oddělili sedimentáciou, roztok mal hodnotu pH 6,6.The procedure of Example 1 was followed except that calcium sludge containing 41% by weight of calcium hydroxide, 3.8% by weight of calcium salt of captax and 13.1% by weight of pitch was used for neutralization. The pH after neutralization was 6.5. Insoluble matter was separated by sedimentation, the solution had a pH of 6.6.

Vynález je možné použit pri neutralizácii odpadnej kyseliny chlorovodíkovej, ktorá odpadá pri výrobě 3-metyl-4-nitrofenolu. Na neutralizáciu sa použijú odpadné kaly, ktoré odpadajú pri výrobě kaptaxu.The invention is applicable to the neutralization of waste hydrochloric acid which is lost in the production of 3-methyl-4-nitrophenol. For neutralization, waste sludge is used which falls off during the production of the captax.

Claims

3, 247586 and 13.1% by weight of pitch-like substances. The pH after neutralization was 6.5. The insolubles were separated by sedimentation, the solution had a pH of 6.6. The invention can be used to neutralize the waste hydrochloric acid which is lost in the production of 3-methyl-4-nitrophenol. For neutralization, sludge is used which is not used in the production of the capta. BEFORE THE METALLY A method of neutralizing waste hydrochloric acid from the production of 3-methyl-4-nitrophenol containing sodium chloride, 3-methyl-4-nitrophenol, 3-methyl-4-nitrosophenol, 3-methylphenol, nitric acid and nitrous acid, with calcium hydroxide as impurities characterized in that the waste hydrochloric acid is neutralized with the waste calcium hydroxide from the 2-mercaptobenzothiazole containing 3 to 50% by weight of calcium hydroxide, 0.1 to 5% by weight of the calcium salt of 2-mercaptobenzothiazole, 1 to 20% by weight of pitch-like substances produced in the manufacture of the captax, to a final pH of from 2 to 7, preferably from 3 to 6, and from the reaction mixture the precipitated impurities are separated, preferably by sedimentation.