GB2079308A

GB2079308A - Pitch-like products and process for their preparation

Info

Publication number: GB2079308A
Application number: GB8118007A
Authority: GB
Original assignee: Ruetgerswerke AG
Current assignee: Ruetgers Germany GmbH
Priority date: 1980-07-05
Filing date: 1981-06-11
Publication date: 1982-01-20
Also published as: DE3025612C2; DE3025612A1; GB2079308B; FR2486092A1; FR2486092B1

Abstract

A pitch-like product having a softening point in the range from 70 to 180 DEG C, a sulphur content of 4 to 9%, a quinoline-insolubles content of 0.2 to 3%, atoluene-insolubles content of 32 to 50%, and a C/H ratio of 1.25 to 1.65% can be produced from a coal-based or petroleum-based oil boiling in the range from 210 to 450 DEG C by reacting with 15 to 25% sulphur at a temperature of 115 to 160 DEG C and heating the resultant oil-sulphur adduct to 180 DEG C or more.

Description

SPECIFICATION Pitch-like products and process for their preparation The invention relatesto new pitch-like products prepared by converting coal-based or petroleumbased oils with sulphur.

The pitches normally obtained in the distillation of tars can be used for a wide variety of purposes, for example as binders for briquettes, synthetic coals, electrodes, mineral substances or cellulose fibres, in the production of road tar, roofing strips or pitch coke, and also in lacquers, sealants or insulating compositions. There is accordingly a great economic demand for these substances, and possible ways are being sought artificially to enlarge pitch resources so as to meet the corresponding demand.

On the other hand, there are only limited possible uses for certain tar oils formed in tar distillation as well as for certain fractions produced during petroleum distillation, with the result that from the raw materials' aspect, it is expedient to convert these oils into higher grade, pitch-like substances.

The object of the invention is thus to produce pitch-like products from such oils.

The solution of this objective according to the invention resides in new pitch-like products having a softening point in the range from 70 to 180 C, a sul phur content of 4 to 9%, a content of quinolineinsoluble constituents of 0.2 to 3%, a content of toluene-insoluble constituents of 32 to 50%, and a C/H ratio of 1.25 to 1.65%.

These synthetic pitches can be produced by reacting coal-based or petroleum-based oils with 15 to 25% by weight sulphur at temperatures of 115 to 1 60 C, followed by heating the tar oil/su iphur adduct for several hours at temperatures of 180 to 300 C.

One reaction of sulphur with tar oils or mineral oils, the so-called sulphurisation of these oils, is known, in which the oils are heated (at about 200 C) with about 1 to 2% of sulphur, whereupon the oils thicken and solid lubricants are produced.

In otherprocessestar, mineral oil, ortaroil is boiled with dilute sulphuric acid with the addition of colophony or resin oil, and a synthetic rubber, mod if wed resin or synthetic asphalt is thus produced.

French Patent Specification 1 112 076 describes the production of synthetic asphalt by treating tar or tar oils with sulphur or sulphur dichloride. In this reaction the consolidation is achieved by addition of suiphurto existing double bonds, and no development of gases is observed since the temperature of about 1 00 C is too low for condensation reactions.

In contrast, according to German Reichspatent332 888, anthracene residues with sulphur (about 1 to 2%) are treated so energetically and for such a length of time with sulphur that a substance that can be used as an asphalt substitute is formed.

Likewise, UK Patent Specification 306 421 describes a pitch formed as a polymerisation product from tar oils and sulphur. As in the two aforementioned specifications, in this case also relatively little (1 to 3%) sulphur is used in the reaction at 200 to 300 C, i.e. the amount of sulphur employed is released almost quantitatively during the reaction as hydrogen sulphide.

In contrast to this, in the process of the present inveniton the pitch products according to the invention are produced by reacting coal-based or petroleum-based oils with 15 to 25% sulphur firstly at temperatures of 115 to 1 60 C, i.e. at temperatures slightly above the melting point of sulphur. Initial reactions already take place, sulphur adding on to the reactive centres present in the oils. initial crosslinkages are formed and the viscosity of the reaction mixture increases. The temperature is then increased to above 1 80 C, and a second reaction possibility of sulphur occurs. The sulphur acts as a dehydrogenation agent and is released as hydrogen sulphide.New reactive centres are thereby formed in the oils, which can either cross-link directly with one another or via sulphur bridges. By varying the amount of sulphur as well as the reaction time (say 1 to 3 hours) and temperatures (say 180 to 300 C, especially about 280 C), any desired softening point within the range 70 to 180 C can be established. In order to ensure the plasticity of the pitches according to the invention, the percentage additions of sulphur referred to the stoichiometric hydrogen equivalents of the oils employed are in each case set below 40%, and even below 25% when using filtered anthracene oil.

Coal-based and also petroleum-based oils such as anthracene oils (boiling point range 300 to 450 C), wash oils (boiling point range 230 to 290 C) or also pyrolysis residue oils from olefin plants and their distillation fractions (boiling point range 210 to 410 C) can be used as starting materials. These oils are almost quantitatively converted. It is not neces sary subsequently to distil off oil.

The pitches obtained according to the invention are characterised by low levels (0.2 to 3%) of quinoline-insoluble constituents, whereas the levels of toluene-soluble constituents, namely 30 to 50%, are in the range of good commercial normal and hard pitches. Possible uses forthe pitches according to the invention include, e.g., insulation, coating or sealing applications.

The following examples describe pitches according to the invention and their preparation: Examplesland2 2509 offiltered anthracene oil, a liquid fraction obtained from coaltar distillation (boiling point range 300 to 450 C), was mixed at 130 for 15 minutes with 15% by weight and 16.25% by weight respectively of liquid sulphur, and then heated over the course of 1.5 hours to 280 C. Starting at about 170 C there was a marked evolution of hydrogen sulphide, and these gases were removed in caustic soda in a manner known peruse. The reaction mixtures were left for a further hour at 280 C. After cooling, two pitches were obtained whose properties are summarised in the following Table and are compared with a blind sample in which filtered anthracene had been subjected to the same treatment butwithoutthe addition of sulphur.

Table 1 Example Example Blind 1 2 Sample Sulphur addition (%bywt) 15 16.25 Softening point ( C) (KS) 69 94 S Content (%) 4.35 5.01 1.21 Ql (%)2) 0.3 0.5 - TI (%) 3) 32.9 36.8 0.05 C/H ration 1.62 1.62 1.35 Yield (%) 4) 82 1 ) Softening point according to Kramer-Sarnow 2) Ql = quinoline-insoluble constituents 3) TI = toluene-insoluble constituents 4) Referred to anthracene oil employed Examples 3 to 6 Various coal-based or petroleum-based oils were mixed with different amounts of sulphur at 130 to 1 50 C similar to the procedure described for Examples 1 and 2, heated to 260 to 280 C within 1.5 hours and leftfor2 hours atthistemperature.

The valuesforthe pitches produced are listed in the following Table: Table 2 Example3 Example4 Example5 Example6 Oil em- Coaltarl Coalfarl Coaltarl Pyrolysis oil ployed wash oil mixed oil mixed oil fraction from {Boiling point the steam range 210-280 C) cracking of gas oil to olefins Sulphur addition ( /O by wt) 25 15 20 15 Softening Point ( C) 82 108 180 93 (K.S.) S. Content (%) 5.57 5.07 8.90 7.64 QI (%) 0.3 1.- 3.1 0.2 TI ( /O) 42.1 41.1 50.7 34.3 C/H ration 1.55 1.55 1.62 1.27 Yield (%)" 102 104 102 101 1) Referred to the oil employed

Claims

1. A pitch-like product having a softening point in the rangefrom70to 180 C, a sulphurcontentof4to 9%, a quinoline-insolubles content of 0.2 to 3%, a toluene-insolubles content of 32 to 50%, and a C/H ratio of 1.25 to 1.65%.

2. Aprocessforproducing a pitch-like product, wherein a coal-based or petroleum-based oil boiling in the range from 210 to 450 C is reacted with 15 to 25%sulphurat a temperature of 115 to 160 C and the resultant oil-sulphur adductthen heated to 180 C or more.

3. A process according to Claim 2, wherein the oil is a tar oil.

4. A process according to Claim 3, wherein the oil is filtered anthracene oil having a boiling point range of 300 to 450 C.

5. A process according to Claim 2, wherein the oil is a petroleum-based aromatic oil.

6. A process according to any of Claims 2 to 5, wherein the oil/sulphur adduct is heated to about 280 C.

7. A process according to any of Claims 2 to 6, wherein the oil/sulph ur adduct is heated for 1 to 3 hours.