Libreoffice Preview

Hi, Im follow this steps to preview libreoffice files, but without success. Im using Centos 7.2.

I need help configuring it, thanks in advance:

My config file:
'enable_previews' => 'true',
'preview_libreoffice_path' => '/usr/bin/libreoffice',
);

PHP version:
PHP 5.5.38 (cli) (built: Jul 21 2016 12:25:20)
Copyright (c) 1997-2015 The PHP Group
Zend Engine v2.5.0, Copyright (c) 1998-2015 Zend Technologies
with Zend OPcache v7.0.6-dev, Copyright (c) 1999-2015, by Zend Technologies

Libreoffice path:
->which libreoffice
/usr/bin/libreoffice

->ls /usr/bin/libreoffice -lah
-rwxr-xr-x. 1 apache root 372 Ago 29 10:59 /usr/bin/libreoffice

Libreoffice packets:
->rpm -qa | grep libreoffice
libreoffice-opensymbol-fonts-4.3.7.2-5.el7_2.1.noarch
libreoffice-ure-4.3.7.2-5.el7_2.1.x86_64
libreoffice-graphicfilter-4.3.7.2-5.el7_2.1.x86_64
libreoffice-base-4.3.7.2-5.el7_2.1.x86_64
libreoffice-4.3.7.2-5.el7_2.1.x86_64
libreoffice-core-4.3.7.2-5.el7_2.1.x86_64
libreoffice-pyuno-4.3.7.2-5.el7_2.1.x86_64
libreoffice-draw-4.3.7.2-5.el7_2.1.x86_64
libreoffice-headless-4.3.7.2-5.el7_2.1.x86_64
libreoffice-calc-4.3.7.2-5.el7_2.1.x86_64
libreoffice-emailmerge-4.3.7.2-5.el7_2.1.x86_64
libreoffice-impress-4.3.7.2-5.el7_2.1.x86_64
libreoffice-writer-4.3.7.2-5.el7_2.1.x86_64
libreoffice-math-4.3.7.2-5.el7_2.1.x86_64
libreoffice-pdfimport-4.3.7.2-5.el7_2.1.x86_64

File php.ini:
disable_functions =
;open_basedir = ( ** if I set to /usr/bin/ OC stops ** )

Selinux is disabled;

If I run the libreoffice manually it works:
->/usr/bin/libreoffice --headless --convert-to pdf test\ word\ format.doc
convert /var/owncloud/data/admin/files/Documentos/test word format.doc -> /var/owncloud/data/admin/files/Documentos/test word format.pdf using writer_pdf_Export

Hi,

please note:

Older versions of ownCloud also supported the preview generation of other file types such as PDF, SVG or various office documents. Due to security concerns those providers have been disabled by default and are considered unsupported. While those providers are still available, we discourage enabling them, and they are not documented.

from https://doc.owncloud.org/server/9.1/admin_manual/configuration_files/previews_configuration.html

The mentioned provider is: